Effects of short-term moderate versus high intraocular pressure elevation on flicker-induced changes in full- field electroretinogram

Effects of short-term moderate versus high intraocular pressure elevation on flicker-induced changes in full- field electroretinogram | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Effects of short-term moderate versus high intraocular pressure elevation on flicker-induced changes in full- field electroretinogram Milan Rai, Xiayin Yang, Kai Yip Choi, Shaoying Tan, Henry Ho-lung Chan This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7925173/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 6 You are reading this latest preprint version Abstract Purpose Transient flickering light stimulation (FLS) enhances the electrical activity in the middle retinal layer (MRL) of wild-type mice. This study investigates how short-term moderate and high intraocular pressure (IOP) elevation influences flicker-induced enhancement in the retinal activity using full-field electroretinogram (ffERG). Methods Baseline blood pressure (BP), IOP, mean ocular perfusion pressure (OPP), and ffERG were measured before and after FLS in eighteen C57BL6J mice. The mice were subsequently divided into two groups: ocular hypertension (OHT, n = 9) and control (n = 9). In the OHT group, IOP was firstly transiently elevated to ~ 35 mm Hg for 5 minutes (termed as Loop on Phase-1 (LOP-1)) using an adjustable vascular loop in one randomly chosen eye, while the control group had the loop placed without IOP elevation. IOP was further elevated to ~ 65 mm Hg in the same eye for another 5 minutes (termed as Loop on Phase-2 (LOP-2)) in the OHT group, while the control group had the loop placed in the same eye without IOP increase. The BP, IOP, mean OPP and ffERG measurements were repeated before and after FLS in each condition. Results While BP showed no significant differences, mean OPP was significantly reduced at LOP-1 and LOP-2 in the OHT group compared to both baseline (p < 0.001) and the control group (p < 0.001). The b-wave amplitudes recorded after FLS were significantly higher than those before FLS at baseline and LOP-1 conditions in both control (p < 0.01) and OHT groups (p 0.05) between pre- and post-FLS b-wave amplitudes, while the control group exhibited a significant increase (p < 0.001). The percentage change in b-wave amplitude was significantly reduced in the OHT group at LOP-2 condition (Pre-Loop vs LOP-2: p < 0.01; LOP-1 vs LOP-2: p < 0.001), while the control group maintained a consistent percentage increase in b-wave amplitudes. No such significant changes were found in other parameters of ffERG response after FLS. Conclusions Short-term high IOP elevation (~ 65 mm Hg), but not moderate (~ 35 mm Hg), disrupted flicker-induced enhancement of MRL electrical activity. This implies that the retina can adapt to a short period of moderate IOP, sustaining a normal increase in the retinal electrical activity in response to FLS. However, even a short period of high IOP would cause certain physiological damage to the retina. flickering light stimulation middle retinal layer vascular loop ocular perfusion pressure electrical activity Figures Figure 1 Figure 2 Figure 3 Figure 4 Introduction Elevated intraocular pressure (IOP) is one of the most well-documented risk factors for glaucoma, a leading cause of irreversible blindness worldwide [ 1 , 2 ]. Increased IOP causes direct mechanical damage to retinal ganglion cell axons [ 3 ] and may also shear astrocyte attachments from the optic nerve head, resulting in the loss of metabolic support [ 4 ]. Moreover, the compression of blood vessels, caused by elevated IOP, may lead to insufficient blood supply, resulting in oxygen and nutrients deprivation [ 5 ]. This deficiency can induce ischemic changes in the retina and optic nerve head, facilitating the progression of glaucomatous damage [ 5 , 6 ]. In addition, the compromised retinal blood flow can adversely alter retinal perfusion pressure, potentially affecting retinal neurovascular coupling (the mechanism by which increased retinal neural activity from light stimuli leads to dilation of retinal vessels and enhanced blood flow) and impairing normal retinal physiology [ 7 ]. Several studies have widely reported the diminishing effects of increased IOP on the structure and function of the retina [ 8 – 11 ]. Currently, the assessments of retinal layer thickness (specifically the retinal nerve fibre layer thickness), optic nerve head appearance, visual fields, and electrophysiological responses are conducted to detect retinal structural and functional changes caused by elevated IOP. However, the changes, such as retinal nerve fibre layer thinning and visual field defects, are often only detectable and measurable once the cumulative damage reaches a certain threshold [ 3 , 12 ]. Recent studies have reported that flicker-evoked increases in retinal blood flow (RBF) and blood vessel diameter are reduced in glaucoma patients compared to healthy subjects [ 13 – 16 ]. Specifically, Riva et al. reported a significant reduction in flicker-induced retinal blood flow responses at the optic disc rim in early open-angle glaucoma and ocular hypertensive patients [ 13 ]. Garhofer et al. found a significant reduction in flicker-induced vasodilation of retinal veins in patients with early glaucoma [ 14 ]. Gugleta et al. reported an impaired flicker-evoked retinal vessel response (vasodilation) in the primary open angle-glaucoma patients [ 15 , 16 ]. These findings suggest that the hemodynamic component of the retinal neurovascular coupling could be impaired by elevated IOP. Although previous studies have assessed the flicker-induced changes in retinal vascular calibres, such as RBF and vasodilation in glaucoma and ocular hypertensive patients [ 13 – 16 ], the effect of elevated IOP on flicker-induced changes in retinal electrophysiological responses (representing neuronal component of neurovascular coupling) is still unknown. Recently, we have shown that retinal stimulation with flickering light can transiently enhance electro-retinal responses in addition to an increase in RBF in healthy mice [ 18 ]. Our findings suggest that both hemodynamic and neuronal components are transiently enhanced by retinal stimulation with flickering light stimulation (FLS). Although we have assessed and quantified the changes in ffERG responses due to transient FLS in normal mice, the influence of short-term IOP elevation on these changes remains unclear. Therefore, this study aims to investigate the effects of short-term moderate (~ 35 mm Hg) and high (~ 65 mm Hg) IOP elevations on flicker-induced alterations in ffERG responses in a mouse model. In the present study, our primary hypothesis is that short-term IOP elevation would attenuate the flicker-induced increases in ERG responses as elevated IOP has been found to impair the retinal vascular autoregulation [ 17 ]. To test this hypothesis, we measured the retinal neuronal responses before and after FLS using our reported full-field electroretinogram (ffERG) protocols [ 18 ] at three different levels of IOP (~ 15 mm Hg, ~ 35 mm Hg, and ~ 65 mm Hg) and compared the effects of these varying IOP levels on flicker-induced ffERG changes in mice. Methods Animals All experimental procedures were carried out in adherence to the ARVO Statement for the Use of Animals in Ophthalmic and Vision Research. The study protocol was approved by the Animal Ethics Sub-committee of The Hong Kong Polytechnic University (ASESC No.:18–19/58-SO-R-OTHERS). Eighteen C57BL/6J mice (age: 8 weeks, 10 males and 8 females), were housed in the centralised animal facilities in a temperature-controlled room (21–22°C) under normal lighting condition (approximately 200 lux) with a 12/12-hour light/dark cycle. Mice were provided with unrestricted access to food (Pico Lab diet 20 (5053); PMI Nutrition International, Richmond, IN, USA) and water. Experimental Design Following overnight dark adaptation for more than 12 hours, mice were anesthetized via intraperitoneal injection of a cocktail containing 90 mg/kg of 10% ketamine (Alfasan International B.V., Woerden, Holland) and 12 mg/kg of 2% xylazine (Alfasan International B.V.). All eighteen mice underwent baseline blood pressure (BP) and IOP measurements. Then, ffERG responses were recorded before and after FLS according to our previously described experimental protocols [ 18 ] in all mice. BP and IOP measurements were subsequently repeated. Following that, mice were randomly assigned to either the OHT group (n = 9) or the control group (n = 9). In the OHT group, IOP was elevated to approximately 35 mm Hg by adjusting a ligature (adjustable vascular loop) placed around one randomly chosen eye. This elevated IOP was maintained for 5 minutes, during which BP and IOP were measured. After the stabilization period, ffERG measurements were repeated (under elevated IOP condition) before and after FLS, following the same experimental protocol as described above. BP and IOP measurements were then repeated. Thereafter, the loop was gradually untightened and subsequently removed for 5 minutes to minimise the effects of elevated IOP caused by loop tightening. Following this resting period of about 5 minutes, IOP was further elevated to approximately 65 mm Hg by gradually tightening the ligature. This elevated IOP was also sustained for 5 minutes, during which BP and IOP measurements were repeated. After stabilization, ffERG recordings were again repeated (under elevated IOP condition) before and after FLS, as previously described, followed by BP and IOP measurements. In contrast, the control group underwent the same experimental protocols but without any elevation of IOP, thereby maintaining normal IOP throughout the entire procedure. A flowchart depicting the experimental steps is presented in Fig. 1 . IOP manipulation The procedures for inducing IOP elevation have already been described in the previous study [ 19 ]. IOP was manually elevated by using an adjustable loop placed around one randomly chosen eye. The adjustable loop consisted of an 8-cm long small vascular loop (RS PRO Mains 5 Core Power Cable, Red PVC) measuring 1.5 mm in diameter, which was inserted within a plastic tubing (weight: 1.4 g) with a loop of 2 mm internal diameter and a length of 4 cm. The loop was placed anterior to the equator of the eye following the topical administration of local anaesthesia (1% tetracaine; Alcon Laboratories, Ft. Worth, TX, USA). The desired IOP elevation was induced by gradually tightening the vascular loop (~ 5 mm Hg increase in ~ 10 seconds). In the OHT group, the loop was gradually adjusted to elevate IOP at approximately 35 mm Hg during the first phase and at around 65 mm Hg in the second phase. In the control group, the loop was placed without tightening to keep IOP within the normal range throughout both phases. The condition prior to the application of the loop is referred to as Pre-Loop (baseline). The initial phase of loop adjustment is termed as Loop on Phase-1 (LOP-1), while the second phase of adjustment is termed as Loop on Phase-2 (LOP-2). In the OHT group, these phases correspond to the adjustments made to maintain IOP at 35 mm Hg (LOP-1) and 65 mm Hg (LOP-2), respectively. The IOP was measured using the Tonolab tonometer TV02 (ICare, Vantaa, Finland). Additional local anaesthesia (1% tetracaine; Alcon Laboratories, Ft. Worth, TX, USA) was applied to the eye every 15 minutes after loop placement until the end of experiment. An Image captured during the placement of adjustable vascular loop around an eye of a mouse is shown in Fig. 2 . Blood pressure measurement Blood pressure was measured using a non-invasive automated tail-cuff system (Vistech BP-2000 Blood Pressure Analysis System; Vistech Systems; Apex, NC) [ 20 , 21 ]. Mean OPP was calculated as the difference between mean BP and IOP, which is different from the relationship used in humans (OPP = (2/3) MAP − IOP) [ 22 ]. As the ‘2/3’ MAP adjustment factor is only applicable to rodents in an upright position, it was not incorporated in our study, given that mouse BP was measured in a prone position (anesthetized) [ 22 ]. Full-field electroretinogram The procedures and protocols used for recording ffERG measurements were described in detail elsewhere [ 18 ]. Briefly, the ffERG recordings were performed using a Ganzfeld ERG system (Q450; RETI Animal, Roland Consult, Brandenburg an der Havel, Germany). After applying a drop of Provain-POS 0.5% (URSAPHARM, Saarbrücken, Germany) and Mydriacyl 1% (Alcon- Couvreur, Puurs, Belgium) to the eye for anesthesia and pupil dilation respectively, the animal was positioned on a heating pad to maintain its body temperature around 37°C. Lacryvisc gel (Alcon, Rueil-Malmaison, France) was uniformly spread over the cornea to prevent dehydration and opacification of the lens caused by anesthesia-induced optical changes. A 2-mm-diameter gold ring electrode (Roland Consult) was placed on the cornea of each eye for ffERG recording. Reference and ground electrodes were needle electrodes (Item No. U51-426; GVB-geliMED, Bad Segeberg, Germany) inserted into the lateral canthus of each eye and the upper base of the tail, respectively. Impedance was below 5 KΩ for all recordings. Following a 10-minute light adaptation at a background luminance of 1 cd/m², ffERG responses (25 responses, interstimulus interval of 1 second) were subsequently measured by presenting a brief white LED flash (duration: 5 ms) at an intensity of 3.0 cd·s/m². Subsequent to flash stimulation, the animals were allowed to rest for 60 seconds to minimise the aftereffects of the flashes. A 12 Hz square-wave flickering light (with a white LED source at an intensity of 0.1 cd·s/m²) was used to stimulate the retina for 160 seconds. The ffERG measurement was immediately repeated following the cessation of the FLS. The amplitudes and implicit times of the a-wave and the b-wave were extracted for analysis. Data Analysis Data are presented as mean and standard error of the mean (SEM). The mixed-model ANOVA was conducted to assess differences in BP, IOP, OPP, and ffERG responses between the two groups, and within groups, with post-hoc Bonferroni correction for multiple comparisons. The relative changes in ffERG responses at each IOP level are presented as percentage changes from their respective baseline values [(Post FLS – Pre FLS)/Pre FLS]. The mixed-model ANOVA with Bonferroni post-hoc tests was used to compare these percentage changes in flicker-induced ffERG within and between groups. All statistical analyses were performed using SPSS 30.0 (IBM Corp. Armonk, NY, USA). A p-value of less than 0.05 was considered statistically significant. Results The mixed-model ANOVA showed significant effects for both within-group and between groups comparisons, as well as interaction effects for IOP and OPP, but not for BP as shown in Table 1. At baseline (both before and after FLS), there were no significant differences in IOP and OPP between the two groups. However, following loop adjustments, the OHT group showed significantly elevated IOP and reduced OPP compared to the control group in both LOP-1 and LOP-2 conditions (both pre- and post-FLS). There were no significant differences in BP, which remained stable over time both between and within the groups. Table 1 presents the mean (SEM) values of IOP, BP, and OPP for the two experimental groups at baseline and Loop on phases obtained before and after FLS. The individual mean values of BP, IOP, and OPP data obtained from both groups are presented in the Supplementary Material (ESM_1). Table 1. Mean (SEM) values of IOP, BP, and OPP measured before and after FLS in the OHT and control groups at Pre-Loop (Baseline), LOP-1, and LOP-2 conditions. Statistical analyses included main (within-groups and between groups) and interaction effects, with between-groups comparisons conducted at each condition both before and after FLS. A p-value < 0.05 was considered statistically significant. Parameters Group Pre-Loop (Baseline) Before FLS Pre-Loop (Baseline) After FLS LOP-1 Before FLS LOP-1 After FLS LOP-2 Before FLS LOP-2 After FLS Within-group main effect Between-groups main effect Interaction Effect Between groups comparisons (At) Pre-Loop (Baseline) Before FLS Pre-Loop (Baseline) After FLS LOP-1 Before FLS LOP-1 After FLS LOP-2 Before FLS LOP-2 After FLS IOP (mm Hg) OHT 11.67 (0.82) 11.67 (0.91) 36.11 (1.06) 34.44 (1.32) 65.00 (0.75) 64.33 (1.75) < 0.001 < 0.001 0.05 > 0.05 < 0.001 < 0.001 < 0.001 0.05 > 0.05 > 0.05 Control 72.01 (1.19) 70.35 (0.88) 70.98 (1.59) 70.29 (1.49) 71.15 (1.13) 71.16 (0.86) OPP (mm Hg) OHT 61.94 (1.62) 60.42 (1.51) 36.94 (1.34) 37.32 (1.38) 8.57 (1.71) 9.83 (2.26) < 0.001 < 0.001 0.05 > 0.05 < 0.001 < 0.001 < 0.001 < 0.001 Control 59.24 (1.00) 56.79 (1.25) 55.76 (1.49) 55.07 (1.16) 56.92 (0.98) 56.72 (0.79) The OHT group exhibited significantly higher IOP and lower OPP in both LOP-1 and LOP-2 conditions (both pre- and post-FLS) compared to baseline values (both pre- and post-FLS), while no such changes were observed in the control group. Table 2 depicts Bonferroni-adjusted within-group comparisons from the mixed-model ANOVA for IOP and OPP, in the OHT and control groups along with their respective p-values. Table 2. Results of Bonferroni-adjusted post-hoc comparisons (after mixed-model ANOVA) for IOP and OPP within the OHT and control groups at Pre-Loop (Baseline), LOP-1, and LOP-2 conditions, evaluated before and after FLS. Statistical significance was set at p < 0.05. Parameters Group Pre-Loop (Baseline) Before FLS vs Pre-Loop (Baseline) After FLS Pre-Loop (Baseline) Before FLS vs LOP-1 Before FLS Pre-Loop (Baseline) Before FLS vs LOP-1 After FLS Pre-Loop (Baseline) Before FLS vs LOP-2 Before FLS Pre-Loop (Baseline) Before FLS vs LOP-2 After FLS Pre-Loop (Baseline) After FLS vs LOP-1 Before FLS Pre-Loop (Baseline) After FLS vs LOP-1 After FLS Pre-Loop (Baseline) After FLS vs LOP-2 Before FLS Pre-Loop (Baseline) After FLS vs LOP-2 After FLS LOP-1 Before FLS vs LOP-1 After FLS LOP-1 Before FLS vs LOP-2 Before FLS LOP-1 Before FLS vs LOP-2 After FLS LOP-1 After FLS vs LOP-2 Before FLS LOP-1 After FLS vs LOP-2 After FLS LOP-2 Before FLS vs LOP-2 After FLS IOP OHT > 0.05 < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 0.05 < 0.001 < 0.001 < 0.001 0.05 Control > 0.05 > 0.05 > 0.05 > 0.05 > 0.05 > 0.05 > 0.05 > 0.05 > 0.05 > 0.05 > 0.05 > 0.05 > 0.05 > 0.05 > 0.05 OPP OHT > 0.05 < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 0.05 < 0.001 < 0.001 < 0.001 0.05 Control > 0.05 > 0.05 > 0.05 > 0.05 > 0.05 > 0.05 > 0.05 > 0.05 > 0.05 > 0.05 > 0.05 > 0.05 > 0.05 > 0.05 > 0.05 The mixed-model ANOVA showed significant within-group effects for all ffERG responses (amplitudes and implicit times of both the a-wave and b-wave). Significant between-group and interaction effects were detected for the amplitudes, but not for the implicit times, of the a-wave and b-wave. There were significant reductions in the amplitudes of both a-wave and b-wave at LOP-2 (both before and after FLS) in the OHT group when compared to the control group, with no corresponding changes in the implicit times. Table 3 shows the mean (SEM) of amplitudes and implicit times of the a-wave and b-wave of both experimental groups at baseline (Pre-Loop) and both Loop on phases conditions obtained before and after FLS, along with mixed-model ANOVA results and Bonferroni post-hoc comparisons between two groups. The supplementary material (ESM_2) contains the individual ffERG data recorded from both groups. Table 3. Mean (SEM) values of the amplitudes and implicit times of the a-wave and b-wave measured before and after FLS in the OHT and control groups, at three conditions: Pre-Loop (Baseline), LOP-1, and LOP-2. Statistical analyses included main effects (both within and between groups) and interaction effects, with between-group comparisons performed at each condition before and after FLS. Statistical significance was defined as a p-value < 0.05. ERG Parameter Group Pre-Loop (Baseline) Before FLS Pre-Loop (Baseline) After FLS LOP-1 Before FLS LOP-1 After FLS LOP-2 Before FLS LOP-2 After FLS Within-group main effect Between groups main effect Interaction Effect Between groups comparisons (At) Pre-Loop (Baseline) Before FLS Pre-Loop (Baseline) After FLS LOP-1 Before FLS LOP-1 After FLS LOP-2 Before FLS LOP-2 After FLS A-wave amplitude (µV) OHT 15.44 (1.41) 15.73 (2.09) 17.75 (2.16) 20.15 (3.92) 8.10 (0.46) 7.88 (0.51) < 0.01 < 0.001 0.05 > 0.05 > 0.05 > 0.05 < 0.001 < 0.01 Control 17.66 (1.78) 18.40 (3.00) 19.22 (3.61) 19.00 (2.73) 17.52 (2.20) 19.05 (3.79) A-wave implicit time (ms) OHT 18.74 (1.24) 20.12 (1.45) 24.61 (1.41) 23.91 (1.78) 29.61 (3.93) 28.98 (3.93) 0.05 > 0.05 Control 19.90 (0.79) 19.98 (1.27) 24.15 (1.03) 24.45 (1.59) 26.07 (1.28) 25.27 (1.38) B-wave amplitude (µV) OHT 123.88 (3.79) 140.03 (5.41) 116.33 (11.12) 134.68 (11.99) 26.50 (2.90) 26.73 (2.83) < 0.001 < 0.01 0.05 > 0.05 > 0.05 > 0.05 < 0.001 < 0.001 Control 128.44 (11.29) 143.34 (12.23) 136.82 (14.03) 152.87 (14.02) 135.38 (15.87) 151.15 (17.67) B-wave implicit time (ms) OHT 54.11 (2.86) 54.23 (3.08) 61.51 (2.77) 60.23 (2.96) 70.33 (2.23) 69.11 (2.14) 0.05 > 0.05 Control 64.11 (3.98) 62.81 (3.24) 67.01 (4.47) 67.55 (4.90) 69.25 (4.71) 72.06 (5.65) The OHT group showed significant reductions in a-wave amplitudes (both pre- and post-FLS) at LOP-2 condition compared to both baseline (Pre-Loop) and LOP-1 conditions. The implicit times of a-wave at both LOP-1 and LOP-2 were significantly increased compared to Pre-Loop (before FLS), but no such delays were found in comparison to Pre-Loop (after FLS) condition. No significant changes in the amplitudes or implicit times of the a-wave were detected within the control group. The amplitudes of b-wave (after FLS) at Pre-Loop and LOP-1 conditions were significantly increased compared to corresponding b-wave amplitudes (before FLS) in both OHT and control groups. Following FLS, there was a significant increase in b-wave amplitudes at LOP-2 in the control group, but not in the OHT group. The implicit times of b-wave were significantly increased at LOP-2 (both pre- and post-FLS) compared to Pre-Loop (both pre- and post-FLS) in the OHT group. There were no significant changes in the implicit times within the control group. Table 4 presents Bonferroni-adjusted within-group comparisons of ffERG responses from the mixed-model ANOVA for both experimental groups. Table 4. Results of Bonferroni-adjusted post-hoc comparisons (after mixed-model ANOVA) for the amplitudes and implicit times of the a-wave and b-wave within the OHT and control groups at Pre-Loop (Baseline), LOP-1, and LOP-2 conditions, measured before and after FLS. Statistical significance was determined at p < 0.05. ERG Responses Group Pre-Loop (Baseline) Before FLS vs Pre-Loop (Baseline) After FLS Pre-Loop (Baseline) Before FLS vs LOP-1 Before FLS Pre-Loop (Baseline) Before FLS vs LOP-1 After FLS Pre-Loop (Baseline) Before FLS vs LOP-2 Before FLS Pre-Loop (Baseline) Before FLS vs LOP-2 After FLS Pre-Loop (Baseline) After FLS vs LOP-1 Before FLS Pre-Loop (Baseline) After FLS vs LOP-1 After FLS Pre-Loop (Baseline) After FLS vs LOP-2 Before FLS Pre-Loop (Baseline) After FLS vs LOP-2 After FLS LOP-1 Before FLS vs LOP-1 After FLS LOP-1 Before FLS vs LOP-2 Before FLS LOP-1 Before FLS vs LOP-2 After FLS LOP-1 After FLS vs LOP-2 Before FLS LOP-1 After FLS vs LOP-2 After FLS LOP-2 Before FLS vs LOP-2 After FLS A-wave amplitude (µV) OHT > 0.05 > 0.05 > 0.05 < 0.05 0.05 > 0.05 < 0.05 0.05 > 0.05 0.05 0.05 Control > 0.05 > 0.05 > 0.05 > 0.05 > 0.05 > 0.05 > 0.05 > 0.05 > 0.05 > 0.05 > 0.05 > 0.05 > 0.05 > 0.05 > 0.05 A-wave implicit time (ms) OHT > 0.05 < 0.01 < 0.05 < 0.05 0.05 > 0.05 > 0.05 > 0.05 > 0.05 > 0.05 > 0.05 > 0.05 > 0.05 > 0.05 Control > 0.05 > 0.05 > 0.05 > 0.05 > 0.05 > 0.05 > 0.05 > 0.05 > 0.05 > 0.05 > 0.05 > 0.05 > 0.05 > 0.05 > 0.05 B-wave amplitude (µV) OHT 0.05 > 0.05 < 0.001 0.05 > 0.05 < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 < 0.001 0.05 Control 0.05 > 0.05 > 0.05 > 0.05 > 0.05 > 0.05 > 0.05 > 0.05 0.05 > 0.05 > 0.05 > 0.05 0.05 > 0.05 > 0.05 < 0.01 0.05 > 0.05 < 0.01 0.05 > 0.05 > 0.05 > 0.05 > 0.05 > 0.05 Control > 0.05 > 0.05 > 0.05 > 0.05 > 0.05 > 0.05 > 0.05 > 0.05 > 0.05 > 0.05 > 0.05 > 0.05 > 0.05 > 0.05 > 0.05 Discussion To our knowledge, this is the first study to assess the short-term impacts of moderate (~ 35 mm Hg) and high (~ 65 mm Hg) IOP elevations on flicker-evoked changes in ffERG responses in a murine model. The current study demonstrated that transient FLS significantly enhanced the b-wave amplitudes of the ffERG, reflecting increased activity in the MRL layer, even under moderate IOP elevation of ~ 35 mm Hg. However, such enhancement was not observed at the high IOP elevation of approximately 65 mm Hg. Although an IOP value of ~ 35 mm Hg seems moderate compared to other levels in our study, it is important to note that this value is approximately three times higher than the corresponding baseline of around 12 mm Hg. The b-wave amplitudes increased by more than 12% and 15% at the Pre-Loop and LOP-1 conditions, respectively, but the percentage change in b-wave amplitude was significantly reduced in the OHT group at the LOP-2 condition. In contrast, the control group showed consistent increases of 11–13% across all conditions. These findings suggest that the retina can effectively adapt to short-term moderate IOP elevation, but not to high levels, sustaining a normal increase in ffERG b-wave amplitudes in response to the FLS. The significant increases of b-wave amplitudes following FLS at baseline and LOP-1 in the OHT group, as well as at all time points in the control group, align with the findings of our recent study [ 18 ]. Our findings revealed that short-term moderate IOP elevation of 35 mm Hg did not impair the retinal physiology to enhance electrical activity, as shown by increased b-wave amplitudes. This implies some degree of retinal resilience or adaptive capacity to a transient and moderate IOP elevation. In contrast, short-term high IOP elevation of 65 mm Hg almost completely abolished the flicker-induced enhancement of the b-wave. This indicates that the retina cannot sustain increased ERG responses after FLS as the IOP above certain threshold would cause retinal physiological impairment. Tan et al. reported that IOP elevation to 45 mm Hg for 30 minutes significantly increased single flash ERG a-wave and b-wave amplitudes [ 23 ]. These increased amplitudes persisted even after IOP normalization following loop removal. However, significant reductions in retinal functional responses (second harmonic component of ERG response) and total RBF in response to FLS were observed when compared to normal IOP conditions in rats. In contrast, they also mentioned that further elevation of IOP beyond 60 mm Hg resulted in progressive reduction of a-wave and b-wave amplitudes. In line with their results, significant reductions were noted in both a-wave and b-wave amplitudes at around 65 mm Hg in the current study. Notably, apart from the differences in IOP levels and durations of IOP elevation, the flickering frequency and stimulation duration were not consistent between their study (10 Hz for 2 seconds) and our study (12 Hz for 160 seconds). Choh et al. recently reported enhanced ffERG a-wave and b-wave amplitudes when IOP was elevated to the moderate level of 35 mm Hg, using similar techniques utilized in our study [ 24 ]. However, our findings showed no significant changes in the baseline (Pre-Loop) a-wave and b-wave amplitudes compared to LOP-1 at similar IOP levels (~ 35 mm Hg). A key difference between the two studies may be the photopic ffERG measured in mice in our study, whereas Choh et al. recorded scotopic ffERG in rats. These differences could influence the changes in flicker-induced ERG responses. In addition, our study showed a significant increase in b-wave amplitudes after FLS at ~ 35 mm Hg, while b-wave amplitudes measured after FLS were not significantly different from the corresponding baseline (before FLS) at ~ 65 mm Hg. Numerous studies have demonstrated that prolonged chronic IOP elevation below 35 mm Hg can lead to increased nitric oxide production in the retina and optic nerve [ 25 – 27 ]. Further investigation is warranted to explore the effects of flickering light on nitric oxide production under varying acute IOP conditions. In our study, while BP remained consistent in both groups, there was a significant reduction in OPP in the OHT group. Specifically, OPP decreased from 60–62 mm Hg at the Pre-Loop condition to 36–37 mm Hg at LOP-1, and further diminished to 8–10 mm Hg at LOP-2 condition. Previous studies have shown that a severe reduction in OPP could disrupt vascular autoregulation and alter neurovascular coupling in the retina [ 23 , 28 ]. Tan et al. reported reduced flicker-evoked retinal blood flow (RBF) when the OPP was ~ 55 mm Hg in rats [ 23 ]. Similarly, Riva et al. also reported no significant increase in RBF when OPP was ~ 20 mm Hg in cats, which is about twice the OPP induced in LOP-2 condition of our study [ 28 ]. These studies suggest that retinal neurovascular coupling is preserved until OPP decreases beyond a certain threshold. Although the current study did not measure RBF in response to FLS, it can be speculated that reduced OPP may lead to insufficient nutrients and oxygen supply to the retina [ 29 ]. Consequently, this could severely impact the metabolism of retinal neurons, making them less responsive to FLS. This speculation is supported by our previous work, where we observed a significant positive correlation between increased RBF and enhanced b-wave amplitudes in the same strain of mice [ 18 ]. There were several limitations of this study. First, the tightening of the loop might have exerted excessive compressive forces from the exterior inward during model induction. This may differ from real ocular hypertensive conditions, where IOP increases due to elevated pressure originating from within the eyeball, exerting an outward force. Second, we did not measure any corresponding changes in retinal hemodynamic components, such as RBF and vessel diameters. Third, while the target IOP was set at 35 mm Hg and 65 mm Hg in each mouse under LOP-1 and LOP-2 conditions respectively in the OHT group, the observed IOP levels varied due to manual adjustments of the loop, resulting in fluctuations that prevented precise IOP targets. Based on the findings of the present study, future studies can be conducted. Since the present study was limited to just two IOP levels, subsequent studies should investigate the effects of a broader range of IOP levels on flicker-induced changes in retinal electrical activity. Moreover, future investigations should assess how hemodynamic components are altered in response to FLS under these varying IOP levels. Additional research should explore whether the changes observed under acutely elevated IOP conditions are also relevant in acute attack glaucoma conditions. Future studies can be conducted to explore the effects of OPP modulation on flicker-induced changes in retinal electrical activity and hemodynamic components such as RBF, blood flow velocity, and vessel diameter. This would further enhance our understanding of the relationship between IOP, BP, OPP, and vascular autoregulation within the context of retinal neurovascular coupling. In conclusion, flicker-induced transient enhancement in b-wave amplitude remained consistent during short-term IOP elevation to approximately 35 mm Hg, indicating robust retinal adaptability to moderate IOP elevation, despite a significant reduction in OPP. However, the short-term IOP elevation to approximately 65 mm Hg caused a significant reduction in the flicker-induced enhancement of b-wave amplitude. This suggests that mechanical stress caused by high IOP with a severe reduction in OPP surpasses the ability of the retina to adapt to FLS and causes a physiological impairment. Declarations Conflict of interest The authors declare that they have no conflict of interest. Informed consent This article does not contain any studies with human participants performed by any of the authors. Statement of human rights This article does not contain any studies with human participants performed by any of the authors. Statement on the welfare of animals All applicable international, national and/or institutional guidelines for the care and use of animals were followed. All procedures performed in studies involving animals were in accordance with the ethical standards of the institution or practice at which the studies were conducted. Funding This study was supported by the Research Impact Fund (PolyU R5006-21) and the General Research Fund (PolyU 15100222) from the Research Grants Council, Lee Hysan Foundation and Sau Ching Charity Foundation and Research Matching Grant Scheme (PolyU ZH5T) and the InnoHK initiative, and the Hong Kong Special Administrative Region Government. The experiments of this study were also supported by University Core Research Facility in Behavioural and Systems Neuroscience of The Hong Kong Polytechnic University. Author Contribution M.R performed experiments, collected and analyzed data, prepared all figures and tables, wrote and revised the main manuscript text.X.Y assisted in experiments and revised the manuscript text.K.Y.C revised the manuscript text.S.T revised the manuscript text.H.H.L.C conceptualized the study, acquired funding, revised the manuscript, and provided supervision throughout the study Acknowledgements This study was supported by the Research Impact Fund (PolyU R5006-21) and the General Research Fund (PolyU 15100222) from the Research Grants Council, Lee Hysan Foundation and Sau Ching Charity Foundation and Research Matching Grant Scheme (PolyU ZH5T) and the InnoHK initiative, and the Hong Kong Special Administrative Region Government. 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Supplementary Files ESM1BPIOPandOPPData.xlsx Cite Share Download PDF Status: Under Review Version 1 posted Reviews received at journal 29 Dec, 2025 Reviewers agreed at journal 15 Dec, 2025 Reviewers invited by journal 02 Nov, 2025 Editor assigned by journal 25 Oct, 2025 Submission checks completed at journal 25 Oct, 2025 First submitted to journal 22 Oct, 2025 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. 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2","display":"","copyAsset":false,"role":"figure","size":381626,"visible":true,"origin":"","legend":"\u003cp\u003eA photograph depicting an adjustable vascular loop placed around the mouse eye.\u003c/p\u003e","description":"","filename":"image2.png","url":"https://assets-eu.researchsquare.com/files/rs-7925173/v1/dd23a5eb90b496ca84b8e3b9.png"},{"id":95747082,"identity":"ddcd1e20-85f5-4aef-b501-209c9122ab16","added_by":"auto","created_at":"2025-11-12 15:00:13","extension":"jpeg","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":132866,"visible":true,"origin":"","legend":"\u003cp\u003eRepresentative traces of ffERG responses recorded before (blue line) and after (orange line) FLS from the OHT and control groups at three experimental conditions: Pre-Loop (Baseline), LOP-1, and LOP-2.\u003c/p\u003e","description":"","filename":"image3.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-7925173/v1/77ce217c85aad7bd5b5c3099.jpeg"},{"id":95801755,"identity":"0f599990-dbdb-4f28-aa76-615b82a693bd","added_by":"auto","created_at":"2025-11-13 08:26:07","extension":"jpeg","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":306118,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eMean percentage changes (from corresponding baseline at Pre-Loop, LOP-1, and LOP-2 in a-wave amplitude (A), a-wave implicit time (B), b-wave amplitude (C), and b-wave implicit time (D), respectively. \u003c/strong\u003eError bars represent standard error of the mean (SEM). \u003csup\u003e‡\u003c/sup\u003e\u003cem\u003ep\u003c/em\u003e\u0026nbsp;\u0026lt; 0.001: Pre-Loop vs LOP-2 in the OHT group, *\u003cem\u003ep\u003c/em\u003e\u0026nbsp;\u0026lt; 0.01: LOP-1 vs LOP-2 in the OHT group, and \u003csup\u003e#\u003c/sup\u003e\u003cem\u003ep\u003c/em\u003e\u0026nbsp;\u0026lt; 0.001: [ Control group vs OHT group at LOP-2]\u003c/p\u003e","description":"","filename":"image4.jpeg","url":"https://assets-eu.researchsquare.com/files/rs-7925173/v1/66d406e11556c323f90a9c05.jpeg"},{"id":95805505,"identity":"dea8c6ae-395e-449f-b918-4957ded8bbe2","added_by":"auto","created_at":"2025-11-13 08:41:41","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":2570897,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7925173/v1/fb8c8fc9-595f-438b-835d-0156b4bf473a.pdf"},{"id":95747127,"identity":"593378d2-448e-4a5a-a7de-d0f52dedd8db","added_by":"auto","created_at":"2025-11-12 15:00:13","extension":"xlsx","order_by":0,"title":"","display":"","copyAsset":false,"role":"supplement","size":13039,"visible":true,"origin":"","legend":"","description":"","filename":"ESM1BPIOPandOPPData.xlsx","url":"https://assets-eu.researchsquare.com/files/rs-7925173/v1/dc546f4633abc4aa66f1ac1d.xlsx"}],"financialInterests":"No competing interests reported.","formattedTitle":"Effects of short-term moderate versus high intraocular pressure elevation on flicker-induced changes in full- field electroretinogram","fulltext":[{"header":"Introduction","content":"\u003cp\u003eElevated intraocular pressure (IOP) is one of the most well-documented risk factors for glaucoma, a leading cause of irreversible blindness worldwide [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]. Increased IOP causes direct mechanical damage to retinal ganglion cell axons [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e] and may also shear astrocyte attachments from the optic nerve head, resulting in the loss of metabolic support [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]. Moreover, the compression of blood vessels, caused by elevated IOP, may lead to insufficient blood supply, resulting in oxygen and nutrients deprivation [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]. This deficiency can induce ischemic changes in the retina and optic nerve head, facilitating the progression of glaucomatous damage [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e, \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]. In addition, the compromised retinal blood flow can adversely alter retinal perfusion pressure, potentially affecting retinal neurovascular coupling (the mechanism by which increased retinal neural activity from light stimuli leads to dilation of retinal vessels and enhanced blood flow) and impairing normal retinal physiology [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]. Several studies have widely reported the diminishing effects of increased IOP on the structure and function of the retina [\u003cspan additionalcitationids=\"CR9 CR10\" citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]. Currently, the assessments of retinal layer thickness (specifically the retinal nerve fibre layer thickness), optic nerve head appearance, visual fields, and electrophysiological responses are conducted to detect retinal structural and functional changes caused by elevated IOP. However, the changes, such as retinal nerve fibre layer thinning and visual field defects, are often only detectable and measurable once the cumulative damage reaches a certain threshold [\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e, \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]. Recent studies have reported that flicker-evoked increases in retinal blood flow (RBF) and blood vessel diameter are reduced in glaucoma patients compared to healthy subjects [\u003cspan additionalcitationids=\"CR14 CR15\" citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e]. Specifically, Riva et al. reported a significant reduction in flicker-induced retinal blood flow responses at the optic disc rim in early open-angle glaucoma and ocular hypertensive patients [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e]. Garhofer et al. found a significant reduction in flicker-induced vasodilation of retinal veins in patients with early glaucoma [\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e]. Gugleta et al. reported an impaired flicker-evoked retinal vessel response (vasodilation) in the primary open angle-glaucoma patients [\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e, \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e]. These findings suggest that the hemodynamic component of the retinal neurovascular coupling could be impaired by elevated IOP.\u003c/p\u003e\u003cp\u003eAlthough previous studies have assessed the flicker-induced changes in retinal vascular calibres, such as RBF and vasodilation in glaucoma and ocular hypertensive patients [\u003cspan additionalcitationids=\"CR14 CR15\" citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e], the effect of elevated IOP on flicker-induced changes in retinal electrophysiological responses (representing neuronal component of neurovascular coupling) is still unknown. Recently, we have shown that retinal stimulation with flickering light can transiently enhance electro-retinal responses in addition to an increase in RBF in healthy mice [\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e]. Our findings suggest that both hemodynamic and neuronal components are transiently enhanced by retinal stimulation with flickering light stimulation (FLS).\u003c/p\u003e\u003cp\u003eAlthough we have assessed and quantified the changes in ffERG responses due to transient FLS in normal mice, the influence of short-term IOP elevation on these changes remains unclear. Therefore, this study aims to investigate the effects of short-term moderate (~\u0026thinsp;35 mm Hg) and high (~\u0026thinsp;65 mm Hg) IOP elevations on flicker-induced alterations in ffERG responses in a mouse model.\u003c/p\u003e\u003cp\u003eIn the present study, our primary hypothesis is that short-term IOP elevation would attenuate the flicker-induced increases in ERG responses as elevated IOP has been found to impair the retinal vascular autoregulation [\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e]. To test this hypothesis, we measured the retinal neuronal responses before and after FLS using our reported full-field electroretinogram (ffERG) protocols [\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e] at three different levels of IOP (~\u0026thinsp;15 mm Hg, ~\u0026thinsp;35 mm Hg, and ~\u0026thinsp;65 mm Hg) and compared the effects of these varying IOP levels on flicker-induced ffERG changes in mice.\u003c/p\u003e"},{"header":"Methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e\u003ch2\u003eAnimals\u003c/h2\u003e\u003cp\u003eAll experimental procedures were carried out in adherence to the ARVO Statement for the Use of Animals in Ophthalmic and Vision Research. The study protocol was approved by the Animal Ethics Sub-committee of The Hong Kong Polytechnic University (ASESC No.:18\u0026ndash;19/58-SO-R-OTHERS). Eighteen C57BL/6J mice (age: 8 weeks, 10 males and 8 females), were housed in the centralised animal facilities in a temperature-controlled room (21\u0026ndash;22\u0026deg;C) under normal lighting condition (approximately 200 lux) with a 12/12-hour light/dark cycle. Mice were provided with unrestricted access to food (Pico Lab diet 20 (5053); PMI Nutrition International, Richmond, IN, USA) and water.\u003c/p\u003e\u003c/div\u003e\n\u003ch3\u003eExperimental Design\u003c/h3\u003e\n\u003cp\u003eFollowing overnight dark adaptation for more than 12 hours, mice were anesthetized via intraperitoneal injection of a cocktail containing 90 mg/kg of 10% ketamine (Alfasan International B.V., Woerden, Holland) and 12 mg/kg of 2% xylazine (Alfasan International B.V.). All eighteen mice underwent baseline blood pressure (BP) and IOP measurements. Then, ffERG responses were recorded before and after FLS according to our previously described experimental protocols [\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e] in all mice. BP and IOP measurements were subsequently repeated. Following that, mice were randomly assigned to either the OHT group (n\u0026thinsp;=\u0026thinsp;9) or the control group (n\u0026thinsp;=\u0026thinsp;9). In the OHT group, IOP was elevated to approximately 35 mm Hg by adjusting a ligature (adjustable vascular loop) placed around one randomly chosen eye. This elevated IOP was maintained for 5 minutes, during which BP and IOP were measured. After the stabilization period, ffERG measurements were repeated (under elevated IOP condition) before and after FLS, following the same experimental protocol as described above. BP and IOP measurements were then repeated. Thereafter, the loop was gradually untightened and subsequently removed for 5 minutes to minimise the effects of elevated IOP caused by loop tightening. Following this resting period of about 5 minutes, IOP was further elevated to approximately 65 mm Hg by gradually tightening the ligature. This elevated IOP was also sustained for 5 minutes, during which BP and IOP measurements were repeated. After stabilization, ffERG recordings were again repeated (under elevated IOP condition) before and after FLS, as previously described, followed by BP and IOP measurements. In contrast, the control group underwent the same experimental protocols but without any elevation of IOP, thereby maintaining normal IOP throughout the entire procedure. A flowchart depicting the experimental steps is presented in Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\n\u003ch3\u003eIOP manipulation\u003c/h3\u003e\n\u003cp\u003eThe procedures for inducing IOP elevation have already been described in the previous study [\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e]. IOP was manually elevated by using an adjustable loop placed around one randomly chosen eye. The adjustable loop consisted of an 8-cm long small vascular loop (RS PRO Mains 5 Core Power Cable, Red PVC) measuring 1.5 mm in diameter, which was inserted within a plastic tubing (weight: 1.4 g) with a loop of 2 mm internal diameter and a length of 4 cm. The loop was placed anterior to the equator of the eye following the topical administration of local anaesthesia (1% tetracaine; Alcon Laboratories, Ft. Worth, TX, USA). The desired IOP elevation was induced by gradually tightening the vascular loop (~\u0026thinsp;5 mm Hg increase in ~\u0026thinsp;10 seconds). In the OHT group, the loop was gradually adjusted to elevate IOP at approximately 35 mm Hg during the first phase and at around 65 mm Hg in the second phase. In the control group, the loop was placed without tightening to keep IOP within the normal range throughout both phases. The condition prior to the application of the loop is referred to as Pre-Loop (baseline). The initial phase of loop adjustment is termed as Loop on Phase-1 (LOP-1), while the second phase of adjustment is termed as Loop on Phase-2 (LOP-2). In the OHT group, these phases correspond to the adjustments made to maintain IOP at 35 mm Hg (LOP-1) and 65 mm Hg (LOP-2), respectively. The IOP was measured using the Tonolab tonometer TV02 (ICare, Vantaa, Finland). Additional local anaesthesia (1% tetracaine; Alcon Laboratories, Ft. Worth, TX, USA) was applied to the eye every 15 minutes after loop placement until the end of experiment. An Image captured during the placement of adjustable vascular loop around an eye of a mouse is shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\n\u003ch3\u003eBlood pressure measurement\u003c/h3\u003e\n\u003cp\u003eBlood pressure was measured using a non-invasive automated tail-cuff system (Vistech BP-2000 Blood Pressure Analysis System; Vistech Systems; Apex, NC) [\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e, \u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e]. Mean OPP was calculated as the difference between mean BP and IOP, which is different from the relationship used in humans (OPP = (2/3) MAP\u0026thinsp;\u0026minus;\u0026thinsp;IOP) [\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e]. As the \u0026lsquo;2/3\u0026rsquo; MAP adjustment factor is only applicable to rodents in an upright position, it was not incorporated in our study, given that mouse BP was measured in a prone position (anesthetized) [\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e].\u003c/p\u003e\n\u003ch3\u003eFull-field electroretinogram\u003c/h3\u003e\n\u003cp\u003eThe procedures and protocols used for recording ffERG measurements were described in detail elsewhere [\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e]. Briefly, the ffERG recordings were performed using a Ganzfeld ERG system (Q450; RETI Animal, Roland Consult, Brandenburg an der Havel, Germany). After applying a drop of Provain-POS 0.5% (URSAPHARM, Saarbr\u0026uuml;cken, Germany) and Mydriacyl 1% (Alcon- Couvreur, Puurs, Belgium) to the eye for anesthesia and pupil dilation respectively, the animal was positioned on a heating pad to maintain its body temperature around 37\u0026deg;C. Lacryvisc gel (Alcon, Rueil-Malmaison, France) was uniformly spread over the cornea to prevent dehydration and opacification of the lens caused by anesthesia-induced optical changes. A 2-mm-diameter gold ring electrode (Roland Consult) was placed on the cornea of each eye for ffERG recording. Reference and ground electrodes were needle electrodes (Item No. U51-426; GVB-geliMED, Bad Segeberg, Germany) inserted into the lateral canthus of each eye and the upper base of the tail, respectively. Impedance was below 5 KΩ for all recordings. Following a 10-minute light adaptation at a background luminance of 1 cd/m\u0026sup2;, ffERG responses (25 responses, interstimulus interval of 1 second) were subsequently measured by presenting a brief white LED flash (duration: 5 ms) at an intensity of 3.0 cd\u0026middot;s/m\u0026sup2;. Subsequent to flash stimulation, the animals were allowed to rest for 60 seconds to minimise the aftereffects of the flashes. A 12 Hz square-wave flickering light (with a white LED source at an intensity of 0.1 cd\u0026middot;s/m\u0026sup2;) was used to stimulate the retina for 160 seconds. The ffERG measurement was immediately repeated following the cessation of the FLS. The amplitudes and implicit times of the a-wave and the b-wave were extracted for analysis.\u003c/p\u003e\u003cdiv id=\"Sec8\" class=\"Section2\"\u003e\u003ch2\u003eData Analysis\u003c/h2\u003e\u003cp\u003eData are presented as mean and standard error of the mean (SEM). The mixed-model ANOVA was conducted to assess differences in BP, IOP, OPP, and ffERG responses between the two groups, and within groups, with post-hoc Bonferroni correction for multiple comparisons. The relative changes in ffERG responses at each IOP level are presented as percentage changes from their respective baseline values [(Post FLS \u0026ndash; Pre FLS)/Pre FLS]. The mixed-model ANOVA with Bonferroni post-hoc tests was used to compare these percentage changes in flicker-induced ffERG within and between groups. All statistical analyses were performed using SPSS 30.0 (IBM Corp. Armonk, NY, USA). A p-value of less than 0.05 was considered statistically significant.\u003c/p\u003e\u003c/div\u003e"},{"header":"Results","content":"\u003cp\u003eThe mixed-model ANOVA showed significant effects for both within-group and between groups comparisons, as well as interaction effects for IOP and OPP, but not for BP as shown in Table\u0026nbsp;1. At baseline (both before and after FLS), there were no significant differences in IOP and OPP between the two groups. However, following loop adjustments, the OHT group showed significantly elevated IOP and reduced OPP compared to the control group in both LOP-1 and LOP-2 conditions (both pre- and post-FLS). There were no significant differences in BP, which remained stable over time both between and within the groups. Table\u0026nbsp;1 presents the mean (SEM) values of IOP, BP, and OPP for the two experimental groups at baseline and Loop on phases obtained before and after FLS. The individual mean values of BP, IOP, and OPP data obtained from both groups are presented in the Supplementary Material (ESM_1).\u003c/p\u003e\n\u003cdiv class=\"gridtable\"\u003e\n\u003cdiv class=\"colspec\" align=\"left\"\u003e\n\u003cp\u003e\u003cstrong\u003eTable 1.\u003c/strong\u003e Mean (SEM) values of IOP, BP, and OPP measured before and after FLS in the OHT and control groups at Pre-Loop (Baseline), LOP-1, and LOP-2 conditions. Statistical analyses included main (within-groups and between groups) and interaction effects, with between-groups comparisons conducted at each condition both before and after FLS. A p-value \u0026lt; 0.05 was considered statistically significant.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv class=\"colspec\" align=\"left\"\u003e\u0026nbsp;\u003c/div\u003e\n\u003ctable id=\"Taba\" border=\"1\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003eParameters\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003eGroup\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003ePre-Loop\u003c/p\u003e\n\u003cp\u003e(Baseline)\u003c/p\u003e\n\u003cp\u003eBefore FLS\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003ePre-Loop\u003c/p\u003e\n\u003cp\u003e(Baseline)\u003c/p\u003e\n\u003cp\u003eAfter FLS\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003eLOP-1\u003c/p\u003e\n\u003cp\u003eBefore FLS\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003eLOP-1\u003c/p\u003e\n\u003cp\u003eAfter FLS\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003eLOP-2\u003c/p\u003e\n\u003cp\u003eBefore FLS\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003eLOP-2\u003c/p\u003e\n\u003cp\u003eAfter FLS\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003eWithin-group main effect\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003eBetween-groups main effect\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003eInteraction Effect\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd colspan=\"6\" align=\"left\"\u003e\n\u003cp\u003eBetween groups comparisons\u003c/p\u003e\n\u003cp\u003e(At)\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003ePre-Loop\u003c/p\u003e\n\u003cp\u003e(Baseline)\u003c/p\u003e\n\u003cp\u003eBefore FLS\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003ePre-Loop\u003c/p\u003e\n\u003cp\u003e(Baseline)\u003c/p\u003e\n\u003cp\u003eAfter FLS\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eLOP-1\u003c/p\u003e\n\u003cp\u003eBefore FLS\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eLOP-1\u003c/p\u003e\n\u003cp\u003eAfter FLS\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eLOP-2\u003c/p\u003e\n\u003cp\u003eBefore FLS\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eLOP-2\u003c/p\u003e\n\u003cp\u003eAfter FLS\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003e\u003cstrong\u003eIOP\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e(mm Hg)\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u003cstrong\u003eOHT\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e11.67 (0.82)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e11.67 (0.91)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e36.11 (1.06)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e34.44 (1.32)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e65.00 (0.75)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e64.33 (1.75)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026lt;\u0026thinsp;0.001\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026lt;\u0026thinsp;0.001\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026lt;\u0026thinsp;0.001\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u003cstrong\u003eControl\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e12.78 (0.83)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e13.56 (1.03)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e15.22 (0.62)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e15.22 (0.91)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e14.22 (0.46)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e14.44 (0.65)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026lt;\u0026thinsp;0.001\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026lt;\u0026thinsp;0.001\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026lt;\u0026thinsp;0.001\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026lt;\u0026thinsp;0.001\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003e\u003cstrong\u003eBP\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e(mm Hg)\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u003cstrong\u003eOHT\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e73.61 (1.66)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e72.09 (1.41)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e73.05 (1.03)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e71.77 (1.18)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e73.57 (1.36)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e74.16 (1.17)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u003cstrong\u003eControl\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e72.01 (1.19)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e70.35 (0.88)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e70.98 (1.59)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e70.29 (1.49)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e71.15 (1.13)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e71.16 (0.86)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003e\u003cstrong\u003eOPP\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003e(mm Hg)\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u003cstrong\u003eOHT\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e61.94 (1.62)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e60.42 (1.51)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e36.94 (1.34)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e37.32 (1.38)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e8.57 (1.71)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e9.83 (2.26)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026lt;\u0026thinsp;0.001\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026lt;\u0026thinsp;0.001\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026lt;\u0026thinsp;0.001\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026lt;\u0026thinsp;0.001\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026lt;\u0026thinsp;0.001\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026lt;\u0026thinsp;0.001\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026lt;\u0026thinsp;0.001\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u003cstrong\u003eControl\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e59.24 (1.00)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e56.79 (1.25)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e55.76 (1.49)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e55.07 (1.16)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e56.92 (0.98)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e56.72 (0.79)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003c/tr\u003e\n\u003c/tbody\u003e\n\u003c/table\u003e\n\u003c/div\u003e\n\u003cp\u003eThe OHT group exhibited significantly higher IOP and lower OPP in both LOP-1 and LOP-2 conditions (both pre- and post-FLS) compared to baseline values (both pre- and post-FLS), while no such changes were observed in the control group. Table\u0026nbsp;2 depicts Bonferroni-adjusted within-group comparisons from the mixed-model ANOVA for IOP and OPP, in the OHT and control groups along with their respective p-values.\u003c/p\u003e\n\u003cdiv class=\"gridtable\"\u003e\n\u003cdiv class=\"colspec\" align=\"left\"\u003e\n\u003cp\u003e\u003cstrong\u003eTable 2.\u003c/strong\u003e Results of Bonferroni-adjusted post-hoc comparisons (after mixed-model ANOVA) for IOP and OPP within the OHT and control groups at Pre-Loop (Baseline), LOP-1, and LOP-2 conditions, evaluated before and after FLS. Statistical significance was set at p \u0026lt; 0.05.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv class=\"colspec\" align=\"char\"\u003e\u0026nbsp;\u003c/div\u003e\n\u003ctable id=\"Tabb\" border=\"1\"\u003e\n\u003cthead\u003e\n\u003ctr\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003eParameters\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003eGroup\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003ePre-Loop (Baseline) Before FLS\u003c/p\u003e\n\u003cp\u003evs\u003c/p\u003e\n\u003cp\u003ePre-Loop (Baseline) After FLS\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003ePre-Loop (Baseline) Before FLS\u003c/p\u003e\n\u003cp\u003evs\u003c/p\u003e\n\u003cp\u003eLOP-1 Before FLS\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003ePre-Loop (Baseline) Before FLS\u003c/p\u003e\n\u003cp\u003evs\u003c/p\u003e\n\u003cp\u003eLOP-1 After FLS\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003ePre-Loop (Baseline) Before FLS\u003c/p\u003e\n\u003cp\u003evs\u003c/p\u003e\n\u003cp\u003eLOP-2 Before FLS\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003ePre-Loop (Baseline) Before FLS\u003c/p\u003e\n\u003cp\u003evs\u003c/p\u003e\n\u003cp\u003eLOP-2 After FLS\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003ePre-Loop (Baseline) After FLS\u003c/p\u003e\n\u003cp\u003evs\u003c/p\u003e\n\u003cp\u003eLOP-1 Before FLS\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003ePre-Loop (Baseline) After FLS\u003c/p\u003e\n\u003cp\u003evs\u003c/p\u003e\n\u003cp\u003eLOP-1 After FLS\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003ePre-Loop (Baseline) After FLS\u003c/p\u003e\n\u003cp\u003evs\u003c/p\u003e\n\u003cp\u003eLOP-2 Before FLS\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003ePre-Loop (Baseline) After FLS\u003c/p\u003e\n\u003cp\u003evs\u003c/p\u003e\n\u003cp\u003eLOP-2 After FLS\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003eLOP-1 Before FLS\u003c/p\u003e\n\u003cp\u003evs\u003c/p\u003e\n\u003cp\u003eLOP-1 After FLS\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003eLOP-1 Before FLS\u003c/p\u003e\n\u003cp\u003evs\u003c/p\u003e\n\u003cp\u003eLOP-2 Before FLS\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003eLOP-1 Before FLS\u003c/p\u003e\n\u003cp\u003evs\u003c/p\u003e\n\u003cp\u003eLOP-2 After FLS\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003eLOP-1 After FLS\u003c/p\u003e\n\u003cp\u003evs\u003c/p\u003e\n\u003cp\u003eLOP-2 Before FLS\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003eLOP-1 After FLS\u003c/p\u003e\n\u003cp\u003evs\u003c/p\u003e\n\u003cp\u003eLOP-2 After FLS\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003eLOP-2 Before FLS\u003c/p\u003e\n\u003cp\u003evs\u003c/p\u003e\n\u003cp\u003eLOP-2 After FLS\u003c/p\u003e\n\u003c/th\u003e\n\u003c/tr\u003e\n\u003c/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003e\u003cstrong\u003eIOP\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u003cstrong\u003eOHT\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026lt;\u0026thinsp;0.001\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026lt;\u0026thinsp;0.001\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026lt;\u0026thinsp;0.001\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026lt;\u0026thinsp;0.001\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026lt;\u0026thinsp;0.001\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026lt;\u0026thinsp;0.001\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026lt;\u0026thinsp;0.001\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026lt;\u0026thinsp;0.001\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026lt;\u0026thinsp;0.001\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026lt;\u0026thinsp;0.001\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026lt;\u0026thinsp;0.001\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026lt;\u0026thinsp;0.001\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026gt;\u0026thinsp;0.05\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u003cstrong\u003eControl\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003e\u003cstrong\u003eOPP\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u003cstrong\u003eOHT\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026lt;\u0026thinsp;0.001\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026lt;\u0026thinsp;0.001\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026lt;\u0026thinsp;0.001\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026lt;\u0026thinsp;0.001\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026lt;\u0026thinsp;0.001\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026lt;\u0026thinsp;0.001\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026lt;\u0026thinsp;0.001\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026lt;\u0026thinsp;0.001\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026lt;\u0026thinsp;0.001\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026lt;\u0026thinsp;0.001\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026lt;\u0026thinsp;0.001\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026lt;\u0026thinsp;0.001\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u003cstrong\u003eControl\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003c/tbody\u003e\n\u003c/table\u003e\n\u003c/div\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eThe mixed-model ANOVA showed significant within-group effects for all ffERG responses (amplitudes and implicit times of both the a-wave and b-wave). Significant between-group and interaction effects were detected for the amplitudes, but not for the implicit times, of the a-wave and b-wave. There were significant reductions in the amplitudes of both a-wave and b-wave at LOP-2 (both before and after FLS) in the OHT group when compared to the control group, with no corresponding changes in the implicit times. Table\u0026nbsp;3 shows the mean (SEM) of amplitudes and implicit times of the a-wave and b-wave of both experimental groups at baseline (Pre-Loop) and both Loop on phases conditions obtained before and after FLS, along with mixed-model ANOVA results and Bonferroni post-hoc comparisons between two groups. The supplementary material (ESM_2) contains the individual ffERG data recorded from both groups.\u003c/p\u003e\n\u003cdiv class=\"gridtable\"\u003e\n\u003cdiv class=\"colspec\" align=\"left\"\u003e\n\u003cp\u003e\u003cstrong\u003eTable 3.\u003c/strong\u003e Mean (SEM) values of the amplitudes and implicit times of the a-wave and b-wave measured before and after FLS in the OHT and control groups, at three conditions: Pre-Loop (Baseline), LOP-1, and LOP-2. Statistical analyses included main effects (both within and between groups) and interaction effects, with between-group comparisons performed at each condition before and after FLS. Statistical significance was defined as a p-value \u0026lt; 0.05.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv class=\"colspec\" align=\"left\"\u003e\u0026nbsp;\u003c/div\u003e\n\u003cdiv class=\"colspec\" align=\"left\"\u003e\u0026nbsp;\u003c/div\u003e\n\u003ctable id=\"Tabc\" border=\"1\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003eERG Parameter\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003eGroup\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003ePre-Loop\u003c/p\u003e\n\u003cp\u003e(Baseline)\u003c/p\u003e\n\u003cp\u003eBefore FLS\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003ePre-Loop\u003c/p\u003e\n\u003cp\u003e(Baseline)\u003c/p\u003e\n\u003cp\u003eAfter FLS\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003eLOP-1\u003c/p\u003e\n\u003cp\u003eBefore FLS\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003eLOP-1\u003c/p\u003e\n\u003cp\u003eAfter FLS\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003eLOP-2\u003c/p\u003e\n\u003cp\u003eBefore FLS\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003eLOP-2\u003c/p\u003e\n\u003cp\u003eAfter FLS\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003eWithin-group\u003c/p\u003e\n\u003cp\u003emain effect\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003eBetween groups main effect\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003eInteraction Effect\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd colspan=\"6\" align=\"left\"\u003e\n\u003cp\u003eBetween groups comparisons\u003c/p\u003e\n\u003cp\u003e(At)\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003ePre-Loop\u003c/p\u003e\n\u003cp\u003e(Baseline)\u003c/p\u003e\n\u003cp\u003eBefore FLS\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003ePre-Loop\u003c/p\u003e\n\u003cp\u003e(Baseline)\u003c/p\u003e\n\u003cp\u003eAfter FLS\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eLOP-1\u003c/p\u003e\n\u003cp\u003eBefore FLS\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eLOP-1\u003c/p\u003e\n\u003cp\u003eAfter FLS\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eLOP-2\u003c/p\u003e\n\u003cp\u003eBefore FLS\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003eLOP-2\u003c/p\u003e\n\u003cp\u003eAfter FLS\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003e\u003cstrong\u003eA-wave amplitude (\u0026micro;V)\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u003cstrong\u003eOHT\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e15.44 (1.41)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e15.73 (2.09)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e17.75\u003c/p\u003e\n\u003cp\u003e(2.16)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e20.15 (3.92)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e8.10\u003c/p\u003e\n\u003cp\u003e(0.46)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e7.88\u003c/p\u003e\n\u003cp\u003e(0.51)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026lt;\u0026thinsp;0.01\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026lt;\u0026thinsp;0.001\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026lt;\u0026thinsp;0.01\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026lt;\u0026thinsp;0.001\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026lt;\u0026thinsp;0.01\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u003cstrong\u003eControl\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e17.66 (1.78)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e18.40 (3.00)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e19.22\u003c/p\u003e\n\u003cp\u003e(3.61)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e19.00 (2.73)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e17.52 (2.20)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e19.05\u003c/p\u003e\n\u003cp\u003e(3.79)\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003e\u003cstrong\u003eA-wave implicit time (ms)\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u003cstrong\u003eOHT\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e18.74 (1.24)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e20.12 (1.45)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e24.61\u003c/p\u003e\n\u003cp\u003e(1.41)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e23.91 (1.78)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e29.61 (3.93)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e28.98\u003c/p\u003e\n\u003cp\u003e(3.93)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026lt;\u0026thinsp;0.01\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u003cstrong\u003eControl\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e19.90 (0.79)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e19.98 (1.27)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e24.15\u003c/p\u003e\n\u003cp\u003e(1.03)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e24.45 (1.59)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e26.07 (1.28)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e25.27\u003c/p\u003e\n\u003cp\u003e(1.38)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003e\u003cstrong\u003eB-wave amplitude (\u0026micro;V)\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u003cstrong\u003eOHT\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e123.88 (3.79)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e140.03 (5.41)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e116.33 (11.12)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e134.68\u003c/p\u003e\n\u003cp\u003e(11.99)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e26.50 (2.90)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e26.73\u003c/p\u003e\n\u003cp\u003e(2.83)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026lt;\u0026thinsp;0.001\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026lt;\u0026thinsp;0.01\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026lt;\u0026thinsp;0.001\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026lt;\u0026thinsp;0.001\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026lt;\u0026thinsp;0.001\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u003cstrong\u003eControl\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e128.44 (11.29)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e143.34 (12.23)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e136.82 (14.03)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e152.87 (14.02)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e135.38 (15.87)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e151.15 (17.67)\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003e\u003cstrong\u003eB-wave implicit time (ms)\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u003cstrong\u003eOHT\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e54.11 (2.86)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e54.23 (3.08)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e61.51\u003c/p\u003e\n\u003cp\u003e(2.77)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e60.23 (2.96)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e70.33 (2.23)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e69.11\u003c/p\u003e\n\u003cp\u003e(2.14)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026lt;\u0026thinsp;0.001\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u003cstrong\u003eControl\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e64.11 (3.98)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e62.81 (3.24)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e67.01\u003c/p\u003e\n\u003cp\u003e(4.47)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e67.55 (4.90)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e69.25\u003c/p\u003e\n\u003cp\u003e(4.71)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e72.06\u003c/p\u003e\n\u003cp\u003e(5.65)\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n\u003c/tr\u003e\n\u003c/tbody\u003e\n\u003c/table\u003e\n\u003c/div\u003e\n\u003cp\u003eThe OHT group showed significant reductions in a-wave amplitudes (both pre- and post-FLS) at LOP-2 condition compared to both baseline (Pre-Loop) and LOP-1 conditions. The implicit times of a-wave at both LOP-1 and LOP-2 were significantly increased compared to Pre-Loop (before FLS), but no such delays were found in comparison to Pre-Loop (after FLS) condition. No significant changes in the amplitudes or implicit times of the a-wave were detected within the control group. The amplitudes of b-wave (after FLS) at Pre-Loop and LOP-1 conditions were significantly increased compared to corresponding b-wave amplitudes (before FLS) in both OHT and control groups. Following FLS, there was a significant increase in b-wave amplitudes at LOP-2 in the control group, but not in the OHT group. The implicit times of b-wave were significantly increased at LOP-2 (both pre- and post-FLS) compared to Pre-Loop (both pre- and post-FLS) in the OHT group. There were no significant changes in the implicit times within the control group. Table\u0026nbsp;4 presents Bonferroni-adjusted within-group comparisons of ffERG responses from the mixed-model ANOVA for both experimental groups.\u003c/p\u003e\n\u003cdiv class=\"gridtable\"\u003e\n\u003cdiv class=\"colspec\" align=\"left\"\u003e\n\u003cp\u003e\u003cstrong\u003eTable 4.\u003c/strong\u003e Results of Bonferroni-adjusted post-hoc comparisons (after mixed-model ANOVA) for the amplitudes and implicit times of the a-wave and b-wave within the OHT and control groups at Pre-Loop (Baseline), LOP-1, and LOP-2 conditions, measured before and after FLS. Statistical significance was determined at p \u0026lt; 0.05.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv class=\"colspec\" align=\"char\"\u003e\u0026nbsp;\u003c/div\u003e\n\u003ctable id=\"Tabd\" border=\"1\"\u003e\n\u003cthead\u003e\n\u003ctr\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003eERG Responses\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003eGroup\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003ePre-Loop (Baseline) Before FLS\u003c/p\u003e\n\u003cp\u003evs\u003c/p\u003e\n\u003cp\u003ePre-Loop (Baseline) After FLS\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003ePre-Loop (Baseline) Before FLS\u003c/p\u003e\n\u003cp\u003evs\u003c/p\u003e\n\u003cp\u003eLOP-1 Before FLS\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003ePre-Loop (Baseline) Before FLS\u003c/p\u003e\n\u003cp\u003evs\u003c/p\u003e\n\u003cp\u003eLOP-1\u003c/p\u003e\n\u003cp\u003eAfter FLS\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003ePre-Loop (Baseline) Before FLS\u003c/p\u003e\n\u003cp\u003evs\u003c/p\u003e\n\u003cp\u003eLOP-2 Before FLS\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003ePre-Loop (Baseline) Before FLS\u003c/p\u003e\n\u003cp\u003evs\u003c/p\u003e\n\u003cp\u003eLOP-2\u003c/p\u003e\n\u003cp\u003eAfter FLS\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003ePre-Loop (Baseline) After FLS\u003c/p\u003e\n\u003cp\u003evs\u003c/p\u003e\n\u003cp\u003eLOP-1\u003c/p\u003e\n\u003cp\u003eBefore FLS\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003ePre-Loop (Baseline) After FLS\u003c/p\u003e\n\u003cp\u003evs\u003c/p\u003e\n\u003cp\u003eLOP-1\u003c/p\u003e\n\u003cp\u003eAfter FLS\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003ePre-Loop (Baseline) After FLS\u003c/p\u003e\n\u003cp\u003evs\u003c/p\u003e\n\u003cp\u003eLOP-2 Before FLS\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003ePre-Loop (Baseline) After FLS\u003c/p\u003e\n\u003cp\u003evs\u003c/p\u003e\n\u003cp\u003eLOP-2\u003c/p\u003e\n\u003cp\u003eAfter FLS\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003eLOP-1\u003c/p\u003e\n\u003cp\u003eBefore FLS\u003c/p\u003e\n\u003cp\u003evs\u003c/p\u003e\n\u003cp\u003eLOP-1\u003c/p\u003e\n\u003cp\u003eAfter FLS\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003eLOP-1\u003c/p\u003e\n\u003cp\u003eBefore FLS\u003c/p\u003e\n\u003cp\u003evs\u003c/p\u003e\n\u003cp\u003eLOP-2\u003c/p\u003e\n\u003cp\u003eBefore FLS\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003eLOP-1\u003c/p\u003e\n\u003cp\u003eBefore FLS\u003c/p\u003e\n\u003cp\u003evs\u003c/p\u003e\n\u003cp\u003eLOP-2\u003c/p\u003e\n\u003cp\u003eAfter FLS\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003eLOP-1\u003c/p\u003e\n\u003cp\u003eAfter FLS\u003c/p\u003e\n\u003cp\u003evs\u003c/p\u003e\n\u003cp\u003eLOP-2\u003c/p\u003e\n\u003cp\u003eBefore FLS\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003eLOP-1\u003c/p\u003e\n\u003cp\u003eAfter FLS\u003c/p\u003e\n\u003cp\u003evs\u003c/p\u003e\n\u003cp\u003eLOP-2\u003c/p\u003e\n\u003cp\u003eAfter FLS\u003c/p\u003e\n\u003c/th\u003e\n\u003cth align=\"left\"\u003e\n\u003cp\u003eLOP-2\u003c/p\u003e\n\u003cp\u003eBefore FLS\u003c/p\u003e\n\u003cp\u003evs\u003c/p\u003e\n\u003cp\u003eLOP-2\u003c/p\u003e\n\u003cp\u003eAfter FLS\u003c/p\u003e\n\u003c/th\u003e\n\u003c/tr\u003e\n\u003c/thead\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003e\u003cstrong\u003eA-wave amplitude (\u0026micro;V)\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u003cstrong\u003eOHT\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026lt;\u0026thinsp;0.05\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026lt;\u0026thinsp;0.05\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026lt;\u0026thinsp;0.05\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026lt;\u0026thinsp;0.05\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026lt;\u0026thinsp;0.01\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026lt;\u0026thinsp;0.05\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u003cstrong\u003eControl\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003e\u003cstrong\u003eA-wave implicit time (ms)\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u003cstrong\u003eOHT\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026lt;\u0026thinsp;0.01\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026lt;\u0026thinsp;0.05\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026lt;\u0026thinsp;0.05\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026lt;\u0026thinsp;0.05\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u003cstrong\u003eControl\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003e\u003cstrong\u003eB-wave amplitude (\u0026micro;V)\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u003cstrong\u003eOHT\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026lt;\u0026thinsp;0.001\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026lt;\u0026thinsp;0.001\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026lt;\u0026thinsp;0.001\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026lt;\u0026thinsp;0.001\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026lt;\u0026thinsp;0.001\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026lt;\u0026thinsp;0.001\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026lt;\u0026thinsp;0.001\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026lt;\u0026thinsp;0.001\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026lt;\u0026thinsp;0.001\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026lt;\u0026thinsp;0.001\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u003cstrong\u003eControl\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026lt;\u0026thinsp;0.01\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026lt;\u0026thinsp;0.01\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026lt;\u0026thinsp;0.001\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd rowspan=\"2\" align=\"left\"\u003e\n\u003cp\u003e\u003cstrong\u003eB-wave implicit time (ms)\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u003cstrong\u003eOHT\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026lt;\u0026thinsp;0.01\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026lt;\u0026thinsp;0.05\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026lt;\u0026thinsp;0.01\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u003cstrong\u003e\u0026lt;\u0026thinsp;0.05\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003ctr\u003e\n\u003ctd align=\"left\"\u003e\n\u003cp\u003e\u003cstrong\u003eControl\u003c/strong\u003e\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003ctd align=\"char\" char=\".\"\u003e\n\u003cp\u003e\u0026gt;\u0026thinsp;0.05\u003c/p\u003e\n\u003c/td\u003e\n\u003c/tr\u003e\n\u003c/tbody\u003e\n\u003c/table\u003e\n\u003c/div\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eTo our knowledge, this is the first study to assess the short-term impacts of moderate (~\u0026thinsp;35 mm Hg) and high (~\u0026thinsp;65 mm Hg) IOP elevations on flicker-evoked changes in ffERG responses in a murine model. The current study demonstrated that transient FLS significantly enhanced the b-wave amplitudes of the ffERG, reflecting increased activity in the MRL layer, even under moderate IOP elevation of ~\u0026thinsp;35 mm Hg. However, such enhancement was not observed at the high IOP elevation of approximately 65 mm Hg. Although an IOP value of ~\u0026thinsp;35 mm Hg seems moderate compared to other levels in our study, it is important to note that this value is approximately three times higher than the corresponding baseline of around 12 mm Hg. The b-wave amplitudes increased by more than 12% and 15% at the Pre-Loop and LOP-1 conditions, respectively, but the percentage change in b-wave amplitude was significantly reduced in the OHT group at the LOP-2 condition. In contrast, the control group showed consistent increases of 11\u0026ndash;13% across all conditions. These findings suggest that the retina can effectively adapt to short-term moderate IOP elevation, but not to high levels, sustaining a normal increase in ffERG b-wave amplitudes in response to the FLS.\u003c/p\u003e\u003cp\u003eThe significant increases of b-wave amplitudes following FLS at baseline and LOP-1 in the OHT group, as well as at all time points in the control group, align with the findings of our recent study [\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e]. Our findings revealed that short-term moderate IOP elevation of 35 mm Hg did not impair the retinal physiology to enhance electrical activity, as shown by increased b-wave amplitudes. This implies some degree of retinal resilience or adaptive capacity to a transient and moderate IOP elevation. In contrast, short-term high IOP elevation of 65 mm Hg almost completely abolished the flicker-induced enhancement of the b-wave. This indicates that the retina cannot sustain increased ERG responses after FLS as the IOP above certain threshold would cause retinal physiological impairment.\u003c/p\u003e\u003cp\u003eTan et al. reported that IOP elevation to 45 mm Hg for 30 minutes significantly increased single flash ERG a-wave and b-wave amplitudes [\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e]. These increased amplitudes persisted even after IOP normalization following loop removal. However, significant reductions in retinal functional responses (second harmonic component of ERG response) and total RBF in response to FLS were observed when compared to normal IOP conditions in rats. In contrast, they also mentioned that further elevation of IOP beyond 60 mm Hg resulted in progressive reduction of a-wave and b-wave amplitudes. In line with their results, significant reductions were noted in both a-wave and b-wave amplitudes at around 65 mm Hg in the current study. Notably, apart from the differences in IOP levels and durations of IOP elevation, the flickering frequency and stimulation duration were not consistent between their study (10 Hz for 2 seconds) and our study (12 Hz for 160 seconds). Choh et al. recently reported enhanced ffERG a-wave and b-wave amplitudes when IOP was elevated to the moderate level of 35 mm Hg, using similar techniques utilized in our study [\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e]. However, our findings showed no significant changes in the baseline (Pre-Loop) a-wave and b-wave amplitudes compared to LOP-1 at similar IOP levels (~\u0026thinsp;35 mm Hg). A key difference between the two studies may be the photopic ffERG measured in mice in our study, whereas Choh et al. recorded scotopic ffERG in rats. These differences could influence the changes in flicker-induced ERG responses. In addition, our study showed a significant increase in b-wave amplitudes after FLS at ~\u0026thinsp;35 mm Hg, while b-wave amplitudes measured after FLS were not significantly different from the corresponding baseline (before FLS) at ~\u0026thinsp;65 mm Hg. Numerous studies have demonstrated that prolonged chronic IOP elevation below 35 mm Hg can lead to increased nitric oxide production in the retina and optic nerve [\u003cspan additionalcitationids=\"CR26\" citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e]. Further investigation is warranted to explore the effects of flickering light on nitric oxide production under varying acute IOP conditions. In our study, while BP remained consistent in both groups, there was a significant reduction in OPP in the OHT group. Specifically, OPP decreased from 60\u0026ndash;62 mm Hg at the Pre-Loop condition to 36\u0026ndash;37 mm Hg at LOP-1, and further diminished to 8\u0026ndash;10 mm Hg at LOP-2 condition. Previous studies have shown that a severe reduction in OPP could disrupt vascular autoregulation and alter neurovascular coupling in the retina [\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e, \u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e]. Tan et al. reported reduced flicker-evoked retinal blood flow (RBF) when the OPP was ~\u0026thinsp;55 mm Hg in rats [\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e]. Similarly, Riva et al. also reported no significant increase in RBF when OPP was ~\u0026thinsp;20 mm Hg in cats, which is about twice the OPP induced in LOP-2 condition of our study [\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e]. These studies suggest that retinal neurovascular coupling is preserved until OPP decreases beyond a certain threshold. Although the current study did not measure RBF in response to FLS, it can be speculated that reduced OPP may lead to insufficient nutrients and oxygen supply to the retina [\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e]. Consequently, this could severely impact the metabolism of retinal neurons, making them less responsive to FLS. This speculation is supported by our previous work, where we observed a significant positive correlation between increased RBF and enhanced b-wave amplitudes in the same strain of mice [\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e].\u003c/p\u003e\u003cp\u003eThere were several limitations of this study. First, the tightening of the loop might have exerted excessive compressive forces from the exterior inward during model induction. This may differ from real ocular hypertensive conditions, where IOP increases due to elevated pressure originating from within the eyeball, exerting an outward force. Second, we did not measure any corresponding changes in retinal hemodynamic components, such as RBF and vessel diameters. Third, while the target IOP was set at 35 mm Hg and 65 mm Hg in each mouse under LOP-1 and LOP-2 conditions respectively in the OHT group, the observed IOP levels varied due to manual adjustments of the loop, resulting in fluctuations that prevented precise IOP targets.\u003c/p\u003e\u003cp\u003eBased on the findings of the present study, future studies can be conducted. Since the present study was limited to just two IOP levels, subsequent studies should investigate the effects of a broader range of IOP levels on flicker-induced changes in retinal electrical activity. Moreover, future investigations should assess how hemodynamic components are altered in response to FLS under these varying IOP levels. Additional research should explore whether the changes observed under acutely elevated IOP conditions are also relevant in acute attack glaucoma conditions. Future studies can be conducted to explore the effects of OPP modulation on flicker-induced changes in retinal electrical activity and hemodynamic components such as RBF, blood flow velocity, and vessel diameter. This would further enhance our understanding of the relationship between IOP, BP, OPP, and vascular autoregulation within the context of retinal neurovascular coupling.\u003c/p\u003e\u003cp\u003eIn conclusion, flicker-induced transient enhancement in b-wave amplitude remained consistent during short-term IOP elevation to approximately 35 mm Hg, indicating robust retinal adaptability to moderate IOP elevation, despite a significant reduction in OPP. However, the short-term IOP elevation to approximately 65 mm Hg caused a significant reduction in the flicker-induced enhancement of b-wave amplitude. This suggests that mechanical stress caused by high IOP with a severe reduction in OPP surpasses the ability of the retina to adapt to FLS and causes a physiological impairment.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eConflict of interest\u003c/strong\u003e\u003cp\u003eThe authors declare that they have no conflict of interest.\u003c/p\u003e\u003c/p\u003e\u003cp\u003e\u003cstrong\u003eInformed consent\u003c/strong\u003e\u003cp\u003eThis article does not contain any studies with human participants performed by any of the authors.\u003c/p\u003e\u003c/p\u003e\u003cp\u003e\u003ch2\u003eStatement of human rights\u003c/h2\u003e\u003cp\u003eThis article does not contain any studies with human participants performed by any of the authors.\u003c/p\u003e\u003c/p\u003e\u003cp\u003e\u003cstrong\u003eStatement on the welfare of animals\u003c/strong\u003e\u003cp\u003e All applicable international, national and/or institutional guidelines for the care and use of animals were followed. All procedures performed in studies involving animals were in accordance with the ethical standards of the institution or practice at which the studies were conducted.\u003c/p\u003e\u003c/p\u003e\u003ch2\u003eFunding\u003c/h2\u003e\u003cp\u003eThis study was supported by the Research Impact Fund (PolyU R5006-21) and the General Research Fund (PolyU 15100222) from the Research Grants Council, Lee Hysan Foundation and Sau Ching Charity Foundation and Research Matching Grant Scheme (PolyU ZH5T) and the InnoHK initiative, and the Hong Kong Special Administrative Region Government. The experiments of this study were also supported by University Core Research Facility in Behavioural and Systems Neuroscience of The Hong Kong Polytechnic University.\u003c/p\u003e\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eM.R performed experiments, collected and analyzed data, prepared all figures and tables, wrote and revised the main manuscript text.X.Y assisted in experiments and revised the manuscript text.K.Y.C revised the manuscript text.S.T revised the manuscript text.H.H.L.C conceptualized the study, acquired funding, revised the manuscript, and provided supervision throughout the study\u003c/p\u003e\u003ch2\u003eAcknowledgements\u003c/h2\u003e\u003cp\u003eThis study was supported by the Research Impact Fund (PolyU R5006-21) and the General Research Fund (PolyU 15100222) from the Research Grants Council, Lee Hysan Foundation and Sau Ching Charity Foundation and Research Matching Grant Scheme (PolyU ZH5T) and the InnoHK initiative, and the Hong Kong Special Administrative Region Government. The experiments of this study were also supported by University Core Research Facility in Behavioural and Systems Neuroscience of The Hong Kong Polytechnic University\u003c/p\u003e\u003ch2\u003eData Availability\u003c/h2\u003e\u003cp\u003eData is provided within the manuscript or supplementary information files\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eGBD 2019 Blindness and Vision Impairment Collaborators and Vision Loss Expert Group of the Global Burden of Disease Study (2021) Causes of blindness and vision impairment in 2020 and trends over 30 years, and prevalence of avoidable blindness in relation to VISION 2020: the Right to Sight: an analysis for the Global Burden of Disease Study. 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Exp Eye Res 93(2):141\u0026ndash;155. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.exer.2010.09.002\u003c/span\u003e\u003cspan address=\"10.1016/j.exer.2010.09.002\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"documenta-ophthalmologica","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"doop","sideBox":"Learn more about [Documenta Ophthalmologica](http://link.springer.com/journal/10633)","snPcode":"10633","submissionUrl":"https://submission.nature.com/new-submission/10633/3","title":"Documenta Ophthalmologica","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"flickering light stimulation, middle retinal layer, vascular loop, ocular perfusion pressure, electrical activity","lastPublishedDoi":"10.21203/rs.3.rs-7925173/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7925173/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003ePurpose\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eTransient flickering light stimulation (FLS) enhances the electrical activity in the middle retinal layer (MRL) of wild-type mice. This study investigates how short-term moderate and high intraocular pressure (IOP) elevation influences flicker-induced enhancement in the retinal activity using full-field electroretinogram (ffERG).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMethods\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eBaseline blood pressure (BP), IOP, mean ocular perfusion pressure (OPP), and ffERG were measured before and after FLS in eighteen C57BL6J mice. The mice were subsequently divided into two groups: ocular hypertension (OHT, n = 9) and control (n = 9). In the OHT group, IOP was firstly transiently elevated to \u003cstrong\u003e~\u003c/strong\u003e 35 mm Hg for 5 minutes (termed as Loop on Phase-1 (LOP-1)) using an adjustable vascular loop in one randomly chosen eye, while the control group had the loop placed without IOP elevation. IOP was further elevated to \u003cstrong\u003e~\u003c/strong\u003e 65 mm Hg in the same eye for another 5 minutes (termed as Loop on Phase-2 (LOP-2)) in the OHT group, while the control group had the loop placed in the same eye without IOP increase. The BP, IOP, mean OPP and ffERG measurements were repeated before and after FLS in each condition.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eResults\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eWhile BP showed no significant differences, mean OPP was significantly reduced at LOP-1 and LOP-2 in the OHT group compared to both baseline (p \u0026lt; 0.001) and the control group (p \u0026lt; 0.001). The b-wave amplitudes recorded after FLS were significantly higher than those before FLS at baseline and LOP-1 conditions in both control (p \u0026lt; 0.01) and OHT groups (p \u0026lt; 0.001). In the LOP-2 condition, the OHT group showed no significant difference (p \u0026gt; 0.05) between pre- and post-FLS b-wave amplitudes, while the control group exhibited a significant increase (p \u0026lt; 0.001). The percentage change in b-wave amplitude was significantly reduced in the OHT group at LOP-2 condition (Pre-Loop vs LOP-2: p \u0026lt; 0.01; LOP-1 vs LOP-2: p \u0026lt; 0.001), while the control group maintained a consistent percentage increase in b-wave amplitudes. No such significant changes were found in other parameters of ffERG response after FLS.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConclusions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eShort-term high IOP elevation (~ 65 mm Hg), but not moderate (~ 35 mm Hg), disrupted flicker-induced enhancement of MRL electrical activity. This implies that the retina can adapt to a short period of moderate IOP, sustaining a normal increase in the retinal electrical activity in response to FLS. However, even a short period of high IOP would cause certain physiological damage to the retina.\u003c/p\u003e","manuscriptTitle":"Effects of short-term moderate versus high intraocular pressure elevation on flicker-induced changes in full- field electroretinogram","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-11-12 15:00:08","doi":"10.21203/rs.3.rs-7925173/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"editorInvitedReview","content":"","date":"2025-12-29T23:12:11+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"113236215743466671623326262202197714619","date":"2025-12-15T09:21:33+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-11-02T17:32:33+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-10-25T08:57:07+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-10-25T08:56:23+00:00","index":"","fulltext":""},{"type":"submitted","content":"Documenta Ophthalmologica","date":"2025-10-22T15:30:37+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"documenta-ophthalmologica","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"doop","sideBox":"Learn more about [Documenta Ophthalmologica](http://link.springer.com/journal/10633)","snPcode":"10633","submissionUrl":"https://submission.nature.com/new-submission/10633/3","title":"Documenta Ophthalmologica","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"stoa","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"c7acd1b4-81e5-4716-91a5-9a791553f5ee","owner":[],"postedDate":"November 12th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[],"tags":[],"updatedAt":"2025-11-12T15:00:08+00:00","versionOfRecord":[],"versionCreatedAt":"2025-11-12 15:00:08","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-7925173","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7925173","identity":"rs-7925173","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}