Identification and management of different types of bacillary layer detachment in eyes with rhegmatogenous retinal detachment

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Muni, Isabela M. Melo, and 5 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-9187269/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Purpose: To describe the preoperative and postoperative features of eyes with rhegmatogenous retinal detachment (RRD) and different types of bacillary layer detachment (BALAD). Methods : Retrospective cohort study of patients with primary fovea-off RRD and BALAD who underwent pars plana vitrectomy (PPV). Optical coherence tomography, multicolor images, and logarithm of the minimum angle of resolution (logMAR) best-corrected visual acuities (BCVAs) were obtained preoperatively and at 1, 3, 6, and 12 months after the operation. Three types of BALAD were identified preoperatively on the basis of OCT: cavity, transition and lamellar hole. Results: , among the 42 eyes included, 23 were classified as cavity, 6 as transition and 13 as lamellar hole. All types showed a sharp red round area at the fovea on multicolor images. After standard PPV, additional internal limiting membrane (ILM) peeling was carried out in none eyes with cavity, in 2 eyes with transition and in all BALAD-lamellar hole eyes. Post-operatively, no eyes showed evidence of full-thickness macular hole (FTMH). At 12 months post-operatively, ellipsoid zone (EZ) and external limiting membrane (ELM) appeared continuous in 54.8% (23/42) eyes (20 cavity/transition and 3 BALAD lamellar-hole, P=0.004) and 69% (29/42) eyes (24 cavity/transition and 5 BALAD lamellar-hole, P= 0.006), respectively. Accordingly, BCVA was worse in the eyes with BALAD-lamellar hole than in those with cavity/transition BALAD (0.6 ± 0.4 vs. 0.3 ± 0.2; P= 0.01). Conclusion: multicolor imaging is useful to identify BALAD. Cavity and transition BALAD are likely to not progress to FTMH after retinal reattachment. ILM peeling and cover flap prevented FTMH formation in eyes with BALAD-lamellar hole in this cohort. 12 months postoperatively, restoration rates of integrity of ELM and EZ bands and BCVA scores remained lower in eyes with BALAD-lamellar hole in comparison to those with cavity/transition BALAD. Bacillary layer detachment optical coherence tomography multicolor imaging confocal scanning laser ophthalmoscope rhegmatogenous retinal detachment Figures Figure 1 Figure 2 Figure 3 Figure 4 KEY MESSAGES What is known: Bacillary layer detachment (BALAD) in the context of rhegmatogenous retinal detachment features specific characteristics visible on optical coherence tomography (OCT) but not on ophthalmoscopy or standard fundus photography. BALAD-lamellar hole often evolve into full-thickness macular hole after retinal reattachment. What is new: in addition to OCT, multicolor imaging recorded with a confocal scanning ophthalmoscope is a useful imaging modality for the detection of BALAD, showing a sharp, round orange-red area at the fovea. What is new: Peeling of the internal limiting membrane with creation of inverted flap at the time of retinal detachment repair prevents the formation of full-thickness macular hole in the eyes with BALAD-lamellar hole. INTRODUCTION In 2021, Mehta et al. [ 1 ] introduced the term “bacillary layer detachment” (BALAD) to describe an apparent separation within the photoreceptor inner segment (IS) myoid zone visible on spectral-domain optical coherence tomography (OCT) scans of a patient with toxoplasma-related chorioretinitis. Since then, BALAD has been reported in several series of patients with uveitis, central serous chorioretinopathy and choroidal melanoma. [ 2 – 4 ] In 2023, Melo et al.[ 5 ] identified foveal BALAD in the context of rhegmatogenous retinal detachment (RRD). The results of clinical examination and fundus photographs were reportedly similar in patients with BALAD and controls, so the authors outlined the importance of preoperative OCT for the identification of this abnormality.[ 5 , 6 ] Two main forms of BALAD were identified on the basis of OCT analysis: one characterized by an intraretinal cavity at the fovea bounded anteriorly by the outer nuclear layer (ONL), ELM and remnants of myoid and posteriorly by photoreceptor remnants (“typical” BALAD); the other, defined as BALAD-lamellar hole, characterized by remnants of photoreceptors/inter-photoreceptor matrix (IPM) with an open foveal roof. The authors demonstrated a spectrum of progressively worsening abnormalities where there was s breakdown in the anterior BALAD wall, and hypothesized that “typical” BALAD may evolve into BALAD-lamellar hole and the latter evolve into full-thickness macular hole (FTMH). In fact, more than 80% of the eyes with BALAD-lamellar hole progressed to FTMH after retinal reattachment.[ 5 , 6 ] The authors wanted to attach the retina first and then proceed with PPV/ILM peeling for the remaining FTMH Recently, Fu et al. [ 7 ] have reported that internal limiting membrane (ILM) peeling with ILM flap coverage at the time of RRD repair results in closure of the BALAD-lamellar hole. The primary objectives of the present study were: 1) to evaluate if confocal scanning laser ophthalmoscope (cSLO) multicolor images, differently from standard fundus photography, could help to identify this abnormality. 2) to assess the anatomical and functional outcomes in different types of BALAD following PPV with ILM peeling in selected cases. METHODS This retrospective cohort study included patients who had primary fovea-off RRD with features of BALAD confirmed by OCT imaging and underwent pars plana vitrectomy (PPV) at the University of Molise in Campobasso from January 2019 to July 2024. Patients were excluded if they had a history of vitrectomy or any known ocular disease that could affect foveal morphology; also excluded were the eyes that redetached during the follow-up period. Approval for this retrospective study was obtained from the Institutional Review Board of the University of Molise. All participants provided informed consent, and the study adhered to the tenets of the Declaration of Helsinki. The data collected included demographic characteristics, clinical features, RRD duration based on the onset of central visual loss reported by the patient and logarithm of the minimum angle of resolution (logMAR) best-corrected visual acuity (BCVA), which was tested using the Early Treatment Diabetic Retinopathy Study (ETDRS) chart at 4 m. Imaging Multicolor and OCT images were captured using the Spectralis HRA + OCT (version 1.9.13, Heidelberg Engineering, Heidelberg, Germany) before the operation (baseline) and at 1, 3, 6, and 12 months after the operation. The OCT scan protocol entailed capturing a series of highly dense horizontal and radial sections (B-scans), each approximately 17.5 mm or 9.0 mm long and jointly covering areas of 55 degrees horizontally and 40 degrees vertically (horizontal sections) or 55 degrees (radial sections). According to the OCT characteristics, we recognized three types of BALAD (Fig. 1 ): The first type, characterized by a split at the level of myoid zone, which created a cystic intraretinal space, was named “cavity BALAD”. The second type, characterized by photoreceptor remnants/IPM at the level of the central fovea with an open foveal roof, was named BALAD-lamellar hole. 5,6 Lastly, “transition BALAD” showed a morphology compatible with either cavity or lamellar BALAD in sequential horizontal or vertical scans or in scans with different orientations. Two experienced graders (M.A. and G.R.) independently assessed the pre-operative OCT images. Two other graders (A.C. and C.P.) who were blind to the pre-operative findings and timing of follow-up evaluated the postoperative OCT images. Any discrepancies in their assessments or between preoperative and intraoperative assessments were resolved by a fifth senior grader (P.C.). Preoperatively, the height of the detachment was manually measured using the caliper function in the Spectralis software, as described previously.[ 8 ] Briefly, a line was manually drawn from the outer border of the retina at the fovea perpendicularly to the retinal pigment epithelium using the caliper function, which automatically provided the measured distance in µm. Surgery All eyes underwent 25G or 23G PPV using the Constellation Vision System (Alcon, Fort Worth, TX). A non-contact wide-angle viewing system (Resight Fundus Imaging System, Carl Zeiss Meditec AG, Jena, Germany) was used, and all procedures were performed by a single surgeon (R.d’O.). Before vitrectomy, all phakic eyes underwent phacoemulsification and intraocular lens implantation using the same surgical platform. After standard PPV, all the eyes with BALAD-lamellar hole and two eyes with transition BALAD were subjected to staining of the ILM with trypan blue and Brilliant Blue G (Membraneblue-dual, DORC, Zuidland, The Netherlands). This was followed by peeling of the ILM for 360° at the macula and the creation of an inverted flap covering the hole at the time of RRD repair. No ILM flap insertion was performed in this series. At the end of surgery, 20% sulfur hexafluoride (SF6) gas or silicone oil (SO) with a viscosity of 1000 centistokes was used as an internal tamponade. Regardless of the tamponade agent and break location, all patients were strictly instructed to maintain a face-down position for 24 hours following the operation. The SO was removed within 3 months following PPV. Statistical analysis Continuous variables are presented as the mean ± standard deviation, while categorical variables are presented as an absolute frequency and percentage. Comparisons of logMAR BCVA between subgroups were conducted using the Mann–Whitney test. Comparisons between preoperative demographics characteristics, the integrity of external limiting membrane (ELM) and ellipsoid zone (EZ) and the restoration of foveal bulge, between the eyes with different forms of BALAD, were evaluated using the chi-squared test. Gwet’s AC1 coefficient was used to assess the agreement between graders. The results of multivariable regression analysis are presented as the mean difference ± standard error with 95% confidence intervals (CIs) and P -values. Pearson’s test was used to correlate the height of the cyst on the cavity BALAD with the BCVA recovery. The statistical analysis was performed using SAS v.9.4 TS Level 1M8 (SAS Institute Inc., Cary, NC, USA). P -values < 0.05 were considered statistically significant. RESULTS Among the 42 patients included in the study, 25 (59.5%) were men with a mean age of 62.6 years (± 9.3 SD). Duration of central vision loss, according to patient perception, was 6.7 ± 3.9 days, quadrants of detachment were 2.8 (±0.9), proliferative vitreo-retinopathy Retina Society grade 9 was 0 in 15, A in 18 and B in 9 eyes. The RRD height measured at the fovea was 1668.1 ± 553.4 µm. Cavity BALAD was found in 23 eyes (54.7%), BALAD-lamellar hole was found in 13 eyes (31%), and transition BALAD was found in 6 eyes (14.2%). In eyes with cavity BALAD, the cavity had a variable height ranging from 23 to 410 µm (mean height 102.4 ± 77.2 µm). The hole diameter in the eyes with transition and BALAD-lamellar hole measured 178.3 ± 68.7 µm and 321.4 ± 57.7 µm, respectively. Independently from the type of BALAD visible on OCT, all the eyes showed a sharp orange-red round area at the fovea corresponding to the cyst in cavity/transition BALAD eyes and to the open roof in BALAD-lamellar hole eyes. ( Fig 2 ) Twenty-five eyes (59.5%) had images taken preoperatively at the time of RRD diagnosis and on the day of operation (mean interval between the two recordings: 3.2 ± 1.4 and 3.6 ± 0.9 days). Among these eyes, none with cavity or transition BALAD developed into BALAD-lamellar hole and none with BALAD-lamellar hole evolved into FTMH. All the eyes underwent standard PPV. Two out of 6 eyes with transition BALAD and all the 13 eyes with BALAD-lamellar hole underwent additional ILM peeling and ILM cover flap. At the end of PPV procedure, 17 and 25 eyes received SF6 20% and SO as a tamponade, respectively. Postoperatively, CFT progressively increased throughout the 12 months follow-up period: 1 month 136.4 µm ± 73.3 µm; 3 months: 158.4 µm ± 75.9 µm ; 6 months: 169.8 µm ± 65.9 µm; 12 months: 177.4 µm ± 61.5 µm. Progressive increase of the CFT was significant in the cavity/transition BALAD group (month 1: 116.5 µm ± 43.1 µm; month 12: 165.6 µm ± 48.6 µm, P= 0.006) but not in the BALAD-lamellar hole group (month 1: 212.3 µm ± 95.9 µm; month 12: 229.4 µm ± 92.7 µm, P=0.8) ( Fig 3 ). This result is likely related to the poor restoration of the retinal layers and to the thickness of the flap that remained stable over the course of follow-up. At 1 month postoperatively, only 4 (9.5%) eyes showed a continuous ELM, whereas EZ was discontinuous in all eyes. Twelve months post-operatively 29 (69%) and 23 (54.8%) eyes had recovered a continuous ELM and EZ respectively, with a significant difference between cavity/transition BALAD eyes and BALAD-lamellar hole eyes ( 82.7% vs. 38.5%, P=0.006 and 68.9% vs. 23%, P=0.004) . (Table 1) At 12 months, a visible foveal bulge was observed in 11 eyes (37.9%) with cavity/transition BALAD and in 2 eyes (15.4%) with preoperative BALAD-lamellar hole. (Table 1, Fig 3 ) There was very good inter-grader agreement for determining the integrity of EZ or ELM and the presence of foveal bulge between the two masked readers, with Gwet’s AC1 coefficients of 0.85 (0.81 to 0.93), 0.89 (0.83 to 0.95), and 0.94 (0.90 to 0.0.97), respectively. Preoperative BCVA was 2.0 ± 0.8 logMAR and significantly improved over the course of follow-up (1 month: 0.8 ± 0.5), (3months: 0.5 ± 0.3), (6 months: 0.4 ± 0.2), 12 months: 0.3 ± 0.2). LogMAR BCVA differed significantly between eyes with cavity/transition BALAD and those with BALAD-lamellar hole at all postoperative follow-up visits (0.8 ± 0.4 vs. 1 ± 0.6 at month 1 [ P= 0.025], 0.5 ± 0.23 vs. 0.7 ± 0.4 [ P= 0.03] at month 3, 0.4 ± 0.20 vs. 0.6 ± 0.4 [ P= 0.04] at month 6, 0.3 ± 0.2 vs. 0.6 ± 0.4 [ P= 0.01] at month 12). The height of the cyst in cavity/transition BALAD eyes was not associated with BCVA recovery at the 12-month follow-up. DISCUSSION This retrospective study shows that multicolor imaging is a useful imaging modality for detecting BALAD preoperatively, showing a sharp orange-red round area at the fovea. However, in contrast with OCT, multicolor imaging does not allow the clinician to resolve the three types of BALAD. Following standard PPV and retinal reattachment, in the eyes with cavity/transition BALAD, the BALAD resolved with no progression to BALAD lamellar-hole or FTMH. Peeling of the ILM with creation of an ILM inverted cover flap resulted in closure in BALAD-lamellar hole with no progression to FTMH. Over 12 months of follow-up, eyes with cavity/transition BALAD showed a better rate of restoration of the EZ and ELM bands and foveal bulge in comparison to eyes with BALAD-lamellar hole. Accordingly, BCVA remained significantly worse in the eyes with BALAD-lamellar hole in comparison to those with cavity/transition BALAD. Originally described by Metha et al.[ 1 ] and subsequently observed in various retinal diseases,[ 2 – 4 ] BALAD has recently been reported in the context of RRD.[ 5 – 7 ] In exudative processes, BALAD is hypothesized to occur when outwardly directed forces that support attachment of the photoreceptor OS to the RPE exceed the tensile strength of the photoreceptor IS myoid.[ 10 ] In RRD, the mechanism underlying BALAD formation is thought to be different. The influx of hypo-osmolar liquefied vitreous through an open break progressively detaches the neurosensory retina from the RPE and results in hydration of the outer retina with subsequent changes to the modulus of elasticity of the outer retina, which results in outer corrugations.[ 11 ] Because of its peculiar histological characteristics, particularly the rigid scaffold provided by the Müller cell cone, the outer fovea cannot corrugate. Thus, the stretching forces result in breakdown at the myoid level and formation of an intraretinal foveal cyst (cavity BALAD). More severe conditions cause complete disruption of the inner retinal layers with a bridge of photoreceptor remnants/IPM (BALAD-lamellar hole). Cavity BALAD and BALAD-lamellar hole are at the extremes of a spectrum of progressively increasing abnormalities that include cleavage planes extending from the IS myoid to the Henle fiber layer/ONL and thinning of the ONL as described by Melo et al. [ 5 , 6 ] Thus, as expected, features typical of cavity and BALAD-lamellar hole, can be sometimes visible in the same eye and revealed by differently orientated or spaced apart OCT scans. We named these cases “transition BALAD”, since they may well represent a transient state in the process of evolution from cavity BALAD to BALAD-lamellar hole. Identifying BALAD preoperatively is important because, among the eyes with fovea-off RRD, those with BALAD will have a worse anatomical and functional prognosis. Reportedly, ophthalmoscopy and fundus camera do not show peculiar features in eyes with BALAD.[ 5 , 6 ] Conversely, as shown in this series, multicolor imaging may help to identify BALAD. In fact, multicolor imaging showed a sharp orange-red round area at the fovea in the eyes with BALAD, that corresponded either to the intraretinal cyst ( eyes with cavity/transition BALAD) or to the open roof ( eyes with BALAD-lamellar hole). The main difference between standard fundus cameras and cSLO multicolor device is that the latter combines images obtained by using three different monochromatic laser sources (blue reflectance: 488 nm; green reflectance: 515 nm and infrared reflectance: 820 nm). Such characteristic allows to visualize details at different retinal layers with a better resolution than fundus camera. As a consequence, in eyes with BALAD, the intraretinal cyst or the open foveal roof may result difficult to be detected on ophthalmoscopy or standard fundus photography but are clearly revealed by multicolor images. However, the multicolor imaging cannot resolve the three types of BALAD we distinguished solely on the basis of OCT. Such differentiation is important to plan the optimal surgical approach when using PPV to repair the RRD since only a minority of BALAD-lamellar hole closes after routine PPV (and no ILM peel) with retinal reattachment. In fact, in a prospective series, Melo et al. reported that all eyes with persistent BALAD-lamellar hole following retinal reattachment with pneumatic retinopexy progressed to FTMH suggesting that the bridge of outer retinal tissue in BALAD-lamellar hole is non-viable tissue such as IPM.[ 5 ] In a subsequent retrospective series, the same group [ 6 ] reported that 69% of eyes (20/29) with BALAD-lamellar hole developed into FTMH after RRD repair with pneumatic retinopexy or PPV without ILM peeling. Similarly, Fu et al.[ 7 ] reported that 67% of eyes with BALAD-lamellar hole evolved into FTMH after PPV without ILM peeling. In this study, the eyes with cavity BALAD underwent standard PPV and all the eyes with BALAD-lamellar hole had additional ILM peeling and ILM cover flap. After reattachment, none of the eyes showed evidence of FTMH. Regarding the eyes with transition BALAD, peeling of ILM was performed in 2 out of 6 eyes. After retinal reattachment none of the six eyes progressed to FTMH. Thus, it is likely that the eyes with transition BALAD, similarly to eyes with cavity BALAD, usually do not evolve to FTMH when RRD is repaired with standard PPV. Perhaps the residual intact inner retinal layers visible in eyes with transition BALAD may represent substantial viable tissue, with a smaller defect, ans also potentially serve as a significant scaffold that allows for anatomic restoration and does not result In the development of a FTMH. Thus, routine peeling of ILM in cases with transition BALAD is probably not warranted or even potentially detrimental since it might cause unintentional avulsion of the foveal residual inner layers.[ 12 – 15 ] Conversely, ILM peeling at the time of RRD repair with PPV in eyes with BALAD-lamellar seems to successfully prevent FTMH formation. Similarly to what we found in the present study, Fu et al. [ 7 ] reported that 6 out of 7 eyes (85%) with BALAD-lamellar hole successfully closed after ILM peeling and ILM flap coverage performed concomitant with RRD repair using PPV. Similarly, the closure rate of FTMH developing from BALAD-lamellar hole and requiring subsequent PPV/ILM peeling, has been documented to be 80%. [ 6 ] Melo et al.[ 5 , 6 ] suggested operating on eyes with BALAD in a timely manner since cavity BALAD may develop into BALAD-lamellar hole and ultimately into secondary FTMH. In the present series, no cases of cavity BALAD developed into BALAD-lamellar hole or FTMH after an average period of preoperative observation of 3.5 days. Similarly, Fu et al.[ 7 ] did not report evolution from cavity BALAD to BALAD-lamellar hole in their series. Thus, operating the eyes with BALAD within 3 days from presentation (as generally suggested for the management of non-BALAD fovea-off RRD [ 16 , 17 ]), seems to be reasonable. It is likely that, in addition to the duration of detachment, the extent to which the outer retinal hydration is occurring in a given detachment in a significant factor in the speed at which cavity BALAD will progress to BALAD lamellar hole. Indeed, previous studies [ 5 , 6 ] reported that the height of detachment is the only variable significantly associated with the presence of BALAD. It is important to understand that BALAD in RRD and its subsequent sequelae are a relatively rapid degenerative process that occurs due to hydration-induced structural changes over weeks in untreated RRD. At 12 months postoperatively, overall 54.7% of the eyes showed continuity of the EZ, with significant differences between the cavity/transition and BALAD-lamellar hole groups (68.9% vs. 23%, P = 0.004). These results are similar to those reported by Melo et al. [ 5 , 6 ] in a prospective and a retrospective series (66% and 59% of patients who had OCT imaging at 1 year postoperatively, respectively) and in line with previous observations.[ 18 ] Interestingly, the height of the cyst in cavity BALAD eyes did not correlate with BCVA recovery, which suggests that the split itself, rather than its thickness, is the main cause of photoreceptors damage. This is understandable as the height of the BALAD cavity may simply represent the accumulation of fluid in a potential space. As expected, LogMAR BCVA was significantly worse in BALAD-lamellar hole than in cavity/transition BALAD at all postoperative follow-up visits. [ 5 , 6 ] This suggests that BALAD-lamellar hole cases portend a worse functional prognosis in comparison to cavity BALAD, possibly related to the more severe anatomical damage (disruption of the Müller cells cone and death of the central cones) observed in these eyes. Since all phakic eyes of this series had cataract extraction at the time of RRD repair surgery, the influence of the prevalence of cataract in the different groups and consequently on BCVA, can be excluded. We believe that BALAD-lamellar hole is an end-stage phase of the hydration induced degenerative change occurring to the fovea in dysregulated RRD. This study has various limitations. The small sample size and the retrospective design limit the strength of the conclusions that can be drawn from the data. Furthermore, all patients underwent PPV, a surgical technique that may negatively influence the morphological recovery of normal foveal features after RRD repair in comparison to pneumatic retinopexy or scleral buckling. A comparison between images taken at the time of RRD diagnosis and on the day of operation was available for only about 50% of the patients. Furthermore, the mean time interval between the two examinations was less than 4 days. Thus, the analysis of the possible preoperative development of cavity BALAD into BALAD-lamellar hole and FTMH was limited. Although none of the eyes with BALAD-lamellar hole developed FTMH after retinal reattachment, it remains uncertain whether the anatomical and functional recovery in eyes with BALAD-lamellar hole may be better if ILM peeling is performed concomitantly with RRD repair or at a later time, once the detachment has been repaired, such as would be the case with primary pneumatic retinopexy.. Strengths of this study include the preoperative role of multicolor imaging in addition to OCT for the identification and classification of the three types of BALAD. Furthermore this study suggests that although ILM peeling and cover flap are successful in achieving closure of BALAD-lamellar hole, these surgical manouvers are likely not warranted in eyes with transition BALAD. Thus, an accurate preoperative diagnosis is crucial to consider whether additional procedures (specifically peeling of ILM) at the time of RRD repair may be warranted. Finally, our results suggest that, although a timely intervention in eyes with BALAD is recommended, significant worsening within 3 days from original diagnosis is unlikely. In conclusion, this study highlights that multicolor imaging may help to diagnose BALAD preoperatively, but, in contrast with OCT, does not allow to resolve the different types of BALAD. Cavity and transition BALAD usually do not progress to BALAD-lamellar hole within 3 days from the diagnosis and do not develop into FTMH once the retina has been reattached. In the eyes with BALAD-lamellar hole, ILM peeling and ILM cover flap at the time of RRD repair successfully resulted in hole closure. Over 1 year of postoperative follow-up, restoration rates of integrity/continuity of the ELM/EZ bands/foveal bulge and BCVA remained lower in eyes with BALAD-lamellar hole in comparison to eyes with cavity/transition BALAD, which is expected in light of the advanced degenerative changes in BALAD lamellar-hole. STATEMENTS AND DECLARATIONS Acknowledgments The authors thank the clinical investigator Gerarda Bruno for collecting data and caring for study patients. Funding: This project was supported in part with funding from Next Generation EU, [DM 155711.10.2022]. This project was supported in part with funding from Next Generation EU, in the context of the National Recovery and Resilience Plan for Italy, Rome. Investment PE8-Project Age-It: “Ageing well in an Ageing Society” [DM 155711.10.2022]. The funding organization had no role in the design or conduct of this research. Financial interests: none. Conflict of Interest: The authors declare they have no financial interests. 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Am J Ophthalmol 191:1-6. https://doi.org/10.1016/j.ajo.2018.03.037 Sadeghi E, Colorado-Zavala MF, Almuhtaseb H, Venkatesh R, Parolini B, Chhablani J (2025) Anatomical and functional changes after internal limiting membrane peeling. Surv Ophthalmol 70: 357-368. https://doi.org/10.1016/j.survophthal.2025.01.008 Tao J, Yang J, Wu Y, Ye X, Zhang Y, Mao J, Wang J, Chen Y, Shen L (2022) Internal limiting membrane peeling distorts the retinal layers and induces scotoma formation in the perifoveal temporal macula. Retina 42: 2276-2283. https://doi.org/10.1097/IAE.0000000000003619 Yee C, Xu DN, Berger RF, Traustason KE, Flaxel C (2022) Visual outcomes in macula-involving retinal detachments based on time to surgical repair. Ophthalmic Surg Lasers Imaging Retina 53: 439-444. https://doi.org/10.3928/23258160-20220723-02 Miyake M, Nakao SY, Morino K, Yasukura S, Mori Y, Ishihara K, Muraoka Y, Miyata M, Tamura H, Sakamoto T, Tsujikawa A; Japan-Retinal Detachment Registry Group (2023) Effect of duration of macular detachment on visual prognosis after surgery for macula-off retinal detachment: Japan-retinal detachment registry. Ophthalmol Retina 7: 375-382. https://doi.org/10.1016/j.oret.2023.01.014 dell'Omo R, Viggiano D, Giorgio D, Filippelli M, Di Iorio R, Calo' R, Cardone M, Rinaldi M, dell'Omo E, Costagliola C (2015) Restoration of foveal thickness and architecture after macula- off retinal detachment repair. Invest Ophthalmol Vis Sci 56:1040–1050. https://doi.org/10.1167/iovs.14-15633 Table Table 1. Restoration of continuos ellipsoid zone, external limiting membrane and foveal bulge in eyes with cavity/transition bacillary layer detachment (BALAD) and BALAD-lamellar hole over 12 months of follow-up. Continuous EZ Continuous ELM Presence of foveal bulge Post-op follow-up Cavity/transition BALAD n=29 eyes BALAD-lamellar hole n=13 eyes P Cavity/transition BALAD n=29 eyes BALAD-lamellar hole n=13 eyes P Cavity/transition BALAD n=29 eyes BALAD-lamellar hole n=13 eyes P 1 mo. 0 (0%) 0 (0%) - 4 (13.8%) 0 (0%) 0.02* 0 (0%) 0 (0%) - 3 mo 9 (31%) 0 (0%) 0.009* 13 (44.8%) 0 (0%) 0.0001* 0 (0%) 0 (0%) - 6 mo 16 (55.2%) 1 (7.7%) 0.007* 22 (75.8%) 3 (23.1%) 0.006* 6 (20.7%) 1 (7.7%) 0.03* 12 mo 20 (68.9%) 3 (23%) 0.004* 24 (82.7%) 5 (38.5%) 0.006* 11 (37.9%) 2 (15,4%) 0.04* * statistical significance. EXL= external limiting membrane; EZ=ellipsoid zone; BALAD= bacillary layer detachment; mo= months; post-op= postoperative. Additional Declarations No competing interests reported. Supplementary Files BACILLARYmultimodaldata.xlsx Cite Share Download PDF Status: Posted Version 1 posted 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. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-9187269","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":618169796,"identity":"b332d314-0bdb-4fc9-84de-223609c15ef0","order_by":0,"name":"Marzia Affatato","email":"","orcid":"","institution":"” University of Molise","correspondingAuthor":false,"prefix":"","firstName":"Marzia","middleName":"","lastName":"Affatato","suffix":""},{"id":618169798,"identity":"e6a3a1ba-ae29-4412-a17e-2653cc8fbbcf","order_by":1,"name":"Giuseppe Rapino","email":"","orcid":"","institution":"” University of Molise","correspondingAuthor":false,"prefix":"","firstName":"Giuseppe","middleName":"","lastName":"Rapino","suffix":""},{"id":618169799,"identity":"3660024c-d492-4003-97c1-3f17e3ddc339","order_by":2,"name":"Rajeev H. Muni","email":"","orcid":"","institution":"University of Toronto","correspondingAuthor":false,"prefix":"","firstName":"Rajeev","middleName":"H.","lastName":"Muni","suffix":""},{"id":618169802,"identity":"07da1dc5-ddc8-4d71-9c2d-4d792907a6e9","order_by":3,"name":"Isabela M. Melo","email":"","orcid":"","institution":"University of Toronto","correspondingAuthor":false,"prefix":"","firstName":"Isabela","middleName":"M.","lastName":"Melo","suffix":""},{"id":618169804,"identity":"47a2916e-5a24-4228-a713-911a0b2daf96","order_by":4,"name":"Pasquale Cucciniello","email":"","orcid":"","institution":"” University of Molise","correspondingAuthor":false,"prefix":"","firstName":"Pasquale","middleName":"","lastName":"Cucciniello","suffix":""},{"id":618169807,"identity":"6d01dc04-1bc9-45cf-93ad-fd5bc11a7586","order_by":5,"name":"Angela Maria Castelluzzo","email":"","orcid":"","institution":"” University of Molise","correspondingAuthor":false,"prefix":"","firstName":"Angela","middleName":"Maria","lastName":"Castelluzzo","suffix":""},{"id":618169808,"identity":"3fb58d63-9fe2-4169-bcc1-f84ad448407e","order_by":6,"name":"Tommaso Rossi","email":"","orcid":"","institution":"IRCCS, Fondazione Bietti E.T.S","correspondingAuthor":false,"prefix":"","firstName":"Tommaso","middleName":"","lastName":"Rossi","suffix":""},{"id":618169809,"identity":"42c74928-a67a-4112-96fa-44ff5b2efe31","order_by":7,"name":"Lucia Ziccardi","email":"","orcid":"","institution":"” University of Molise","correspondingAuthor":false,"prefix":"","firstName":"Lucia","middleName":"","lastName":"Ziccardi","suffix":""},{"id":618169810,"identity":"ffcfc55d-de1c-48b2-8d5b-db3a1ea3187f","order_by":8,"name":"Roberto dell’Omo","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA80lEQVRIie3PIQvCQBTA8TcMK+fyBqJf4UTQcuBX2RC2omDU9kTUZHffYml5x4JlmCcKKoLZNW3OUwzKTaPh/uXguB/vHoBK9ZeR5xmVRlF+VAE0BOi/7iXEvhMN76TxIBSI3LwRB8UtBemY1mzOj8MLA2M5wijrMi/YjCfBmUKlLSGVZNWpJ7YLVsKR+6HbC7Z8ul4UfMw0u00L7Rho6mBcDuNekDrTDSkmrasgu4MgHv2BNLXHFE0Q+zshq46FrkusxBG71P2c5LuYhEQSos95hoxVjWXM91nIakbqndLzgLV1lIx59vELs/i9SqVSqQq7AYWrYCL1KislAAAAAElFTkSuQmCC","orcid":"","institution":"” University of Molise","correspondingAuthor":true,"prefix":"","firstName":"Roberto","middleName":"","lastName":"dell’Omo","suffix":""}],"badges":[],"createdAt":"2026-03-21 17:09:05","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-9187269/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-9187269/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":106544508,"identity":"89240b76-6505-4c6c-aa0e-9610b73582dd","added_by":"auto","created_at":"2026-04-09 16:41:11","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":3552587,"visible":true,"origin":"","legend":"\u003cp\u003eTypes of bacillary layer detachment (BALAD) identified by optical coherence tomography (OCT) in eyes with rhegmatogenous retinal detachment. a. Cavity BALAD features a cystic intraretinal space resulting from the split at the level of the myoid zone. The anterior border of the cavity is formed by the external limiting membrane and outer nuclear layer, while the posterior border is delineated by a band of photoreceptor inner (IS) and outer segment (OS) remnants. b. BALAD-lamellar hole is characterized by remnants of photoreceptor IS and OS with an open foveal roof. c,d. Transition BALAD shows either cavity (c) or BALAD-lamellar hole characteristics (d) depending on the position or orientation of OCT scans. The arrows in infrared images show the location and direction of the OCT scans\u003c/p\u003e","description":"","filename":"Fig.1.png","url":"https://assets-eu.researchsquare.com/files/rs-9187269/v1/77402c9b660410c08c946409.png"},{"id":106544430,"identity":"550b4ad9-994e-4404-952e-1a16cbbefa3a","added_by":"auto","created_at":"2026-04-09 16:40:57","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":3224915,"visible":true,"origin":"","legend":"\u003cp\u003eOptical coherence tomography (OCT) and corresponding multicolor images of two eyes with in eyes with rhegmatogenous retinal detachment associated with cavity bacillary layer detachment (BALAD) and BALAD-lamellar hole. a. Cavity BALAD is characterized by an intraretinal cyst at the level of the fovea. b. Multicolor image shows a sharp red-orange circular area corresponding to the cyst visible on OCT. c. BALAD-lamellar hole features remnants of photoreceptor inner and outer segments with an open foveal roof. d. Multicolor image shows a sharp red-orange circular area corresponding to the opening of the roof visible on OCT\u003c/p\u003e","description":"","filename":"Fig.2.png","url":"https://assets-eu.researchsquare.com/files/rs-9187269/v1/ab7494472cf23da4499bc5d4.png"},{"id":106544510,"identity":"c06dd5f8-f89a-41ce-9d1e-8fdf66af676f","added_by":"auto","created_at":"2026-04-09 16:41:12","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":4322621,"visible":true,"origin":"","legend":"\u003cp\u003eAnatomical and functional recovery of fovea-off rhegmatogenous retinal detachment (RRD) eyes with cavity bacillary layer detachment (BALAD). a. Preoperative OCT shows a cavity BALAD characterized by a high cyst. Logarithm of the minimum angle of resolution best-corrected visual acuity (LogMAR BCVA) is 1.4. b. One month after PPV and silicone oil (SO) tamponade, the retina is attached; there is mild edema at the fovea. The ELM and EZ bands are hardly visible. BCVA is 0.7. c. 6 months after RRD repair and 3 months after removal of SO, partial restoration and thickening of ELM and EZ is noted and BCVA has improved to 0.4 d. 12 months postoperatively, ELM and EZ bands appear continuous and the foveal bulge is visible. LogMAR BCVA has improved to 0.3 logMAR. e. Preoperative optical coherence tomography (OCT) shows a cavity BALAD with a thin cyst. f. One month after PPV and SO tamponade, the fovea appears very thin with no visible ELM or EZ. g. 6 months after RRD repair and 4 months after removal of SO, partial restoration and thickening of ELM and EZ is noted. h. 12 months postoperatively, ELM and EZ bands show focal areas of discontinuity, and the foveal bulge is not visible. LogMAR BCVA has improved to 0.5. The white arrows on infrared images show the location and direction of the OCT scans\u003c/p\u003e","description":"","filename":"Fig.3.png","url":"https://assets-eu.researchsquare.com/files/rs-9187269/v1/5035447c57411357056be99a.png"},{"id":106544435,"identity":"5a53dc5c-ceaf-47d8-a028-27c0c7ada28b","added_by":"auto","created_at":"2026-04-09 16:40:58","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":1841000,"visible":true,"origin":"","legend":"\u003cp\u003eOptical coherence tomography (OCT) showing anatomical and functional improvement of an eye with fovea-off rhegmatogenous retinal detachment complicated by bacillary layer detachment (BALAD)-lamellar hole. a. Preoperative OCT demonstrating a BALAD-lamellar hole with a hyperreflective band formed by photoreceptor inner and outer segment remnants (arrowhead) and an open foveal roof. Logarithm of the minum angle of resolution best-corrected visual acuity (LogMAR BCVA) is 1.4. b. One month after pars plana vitrectomy (PPV), internal limiting membrane (ILM) peeling, and cover ILM flap, the fovea has recovered a normal contour and the external limiting membrane (ELM) and ellipsoid zone (EZ) appear discontinuous. The ILM flap covers the foveal surface (arrow). BCVA has improved to 0.8. c. 6 months after operation, the foveal thickness has increased, and the ELM and EZ are partially restored. BCVA is 0.7. d. 12 months after operation, further restoration of the ELM and EZ is noted with residual foci of discontinuitya and BCVA has improved to 0.6. Of note, the thickening of the central foveal thickness results quite modest over the 12-month long follow-up \u0026nbsp;The white arrows on infrared images show the location and direction of the OCT scans\u003c/p\u003e","description":"","filename":"Fig.4.png","url":"https://assets-eu.researchsquare.com/files/rs-9187269/v1/e09ece4b3e5140fe52be3989.png"},{"id":106544636,"identity":"0112fc61-f59e-459b-bf99-a8ac1188a56c","added_by":"auto","created_at":"2026-04-09 16:41:45","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":13477315,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-9187269/v1/6e9f3b45-a97e-4d40-83de-87cad851235d.pdf"},{"id":106544557,"identity":"2047f413-6c79-402c-9c59-50b041158b37","added_by":"auto","created_at":"2026-04-09 16:41:18","extension":"xlsx","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":29771,"visible":true,"origin":"","legend":"","description":"","filename":"BACILLARYmultimodaldata.xlsx","url":"https://assets-eu.researchsquare.com/files/rs-9187269/v1/54fafa723e56c3c9996c448e.xlsx"}],"financialInterests":"No competing interests reported.","formattedTitle":"Identification and management of different types of bacillary layer detachment in eyes with rhegmatogenous retinal detachment","fulltext":[{"header":"KEY MESSAGES","content":"\u003cp\u003e\u003cstrong\u003eWhat is known:\u0026nbsp;\u003c/strong\u003eBacillary layer detachment (BALAD) in the context of rhegmatogenous retinal detachment features specific characteristics visible on optical coherence tomography (OCT) but not on ophthalmoscopy or standard fundus photography. BALAD-lamellar hole often evolve into full-thickness macular hole after retinal reattachment.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eWhat is new:\u0026nbsp;\u003c/strong\u003ein addition to OCT,\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003emulticolor imaging recorded with a confocal scanning ophthalmoscope is a useful imaging modality for the detection of BALAD, showing a sharp, round orange-red area at the fovea.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eWhat is new:\u003c/strong\u003e Peeling of the internal limiting membrane with creation of inverted flap at the time of retinal detachment repair prevents the formation of full-thickness macular hole in the eyes with BALAD-lamellar hole.\u003c/p\u003e"},{"header":"INTRODUCTION","content":"\u003cp\u003eIn 2021, Mehta et al. [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e] introduced the term \u0026ldquo;bacillary layer detachment\u0026rdquo; (BALAD) to describe an apparent separation within the photoreceptor inner segment (IS) myoid zone visible on spectral-domain optical coherence tomography (OCT) scans of a patient with toxoplasma-related chorioretinitis. Since then, BALAD has been reported in several series of patients with uveitis, central serous chorioretinopathy and choroidal melanoma. [\u003cspan additionalcitationids=\"CR3\" citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e]\u003c/p\u003e \u003cp\u003eIn 2023, Melo et al.[\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e] identified foveal BALAD in the context of rhegmatogenous retinal detachment (RRD). The results of clinical examination and fundus photographs were reportedly similar in patients with BALAD and controls, so the authors outlined the importance of preoperative OCT for the identification of this abnormality.[\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e, \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]\u003c/p\u003e \u003cp\u003eTwo main forms of BALAD were identified on the basis of OCT analysis: one characterized by an intraretinal cavity at the fovea bounded anteriorly by the outer nuclear layer (ONL), ELM and remnants of myoid and posteriorly by photoreceptor remnants (\u0026ldquo;typical\u0026rdquo; BALAD); the other, defined as BALAD-lamellar hole, characterized by remnants of photoreceptors/inter-photoreceptor matrix (IPM) with an open foveal roof. The authors demonstrated a spectrum of progressively worsening abnormalities where there was s breakdown in the anterior BALAD wall, and hypothesized that \u0026ldquo;typical\u0026rdquo; BALAD may evolve into BALAD-lamellar hole and the latter evolve into full-thickness macular hole (FTMH). In fact, more than 80% of the eyes with BALAD-lamellar hole progressed to FTMH after retinal reattachment.[\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e, \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e] The authors wanted to attach the retina first and then proceed with PPV/ILM peeling for the remaining FTMH\u003c/p\u003e \u003cp\u003eRecently, Fu et al. [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e] have reported that internal limiting membrane (ILM) peeling with ILM flap coverage at the time of RRD repair results in closure of the BALAD-lamellar hole. The primary objectives of the present study were: 1) to evaluate if confocal scanning laser ophthalmoscope (cSLO) multicolor images, differently from standard fundus photography, could help to identify this abnormality. 2) to assess the anatomical and functional outcomes in different types of BALAD following PPV with ILM peeling in selected cases.\u003c/p\u003e"},{"header":"METHODS","content":"\u003cp\u003eThis retrospective cohort study included patients who had primary fovea-off RRD with features of BALAD confirmed by OCT imaging and underwent pars plana vitrectomy (PPV) at the University of Molise in Campobasso from January 2019 to July 2024. Patients were excluded if they had a history of vitrectomy or any known ocular disease that could affect foveal morphology; also excluded were the eyes that redetached during the follow-up period.\u003c/p\u003e \u003cp\u003e Approval for this retrospective study was obtained from the Institutional Review Board of the University of Molise. All participants provided informed consent, and the study adhered to the tenets of the Declaration of Helsinki.\u003c/p\u003e \u003cp\u003eThe data collected included demographic characteristics, clinical features, RRD duration based on the onset of central visual loss reported by the patient and logarithm of the minimum angle of resolution (logMAR) best-corrected visual acuity (BCVA), which was tested using the Early Treatment Diabetic Retinopathy Study (ETDRS) chart at 4 m.\u003c/p\u003e \u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003eImaging\u003c/h2\u003e \u003cp\u003eMulticolor and OCT images were captured using the Spectralis HRA\u0026thinsp;+\u0026thinsp;OCT (version 1.9.13, Heidelberg Engineering, Heidelberg, Germany) before the operation (baseline) and at 1, 3, 6, and 12 months after the operation. The OCT scan protocol entailed capturing a series of highly dense horizontal and radial sections (B-scans), each approximately 17.5 mm or 9.0 mm long and jointly covering areas of 55 degrees horizontally and 40 degrees vertically (horizontal sections) or 55 degrees (radial sections).\u003c/p\u003e \u003cp\u003eAccording to the OCT characteristics, we recognized three types of BALAD (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e):\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eThe first type, characterized by a split at the level of myoid zone, which created a cystic intraretinal space, was named \u0026ldquo;cavity BALAD\u0026rdquo;. The second type, characterized by photoreceptor remnants/IPM at the level of the central fovea with an open foveal roof, was named BALAD-lamellar hole.\u003csup\u003e5,6\u003c/sup\u003e Lastly, \u0026ldquo;transition BALAD\u0026rdquo; showed a morphology compatible with either cavity or lamellar BALAD in sequential horizontal or vertical scans or in scans with different orientations.\u003c/p\u003e \u003cp\u003eTwo experienced graders (M.A. and G.R.) independently assessed the pre-operative OCT images. Two other graders (A.C. and C.P.) who were blind to the pre-operative findings and timing of follow-up evaluated the postoperative OCT images. Any discrepancies in their assessments or between preoperative and intraoperative assessments were resolved by a fifth senior grader (P.C.).\u003c/p\u003e \u003cp\u003ePreoperatively, the height of the detachment was manually measured using the caliper function in the Spectralis software, as described previously.[\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e] Briefly, a line was manually drawn from the outer border of the retina at the fovea perpendicularly to the retinal pigment epithelium using the caliper function, which automatically provided the measured distance in \u0026micro;m.\u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003eSurgery\u003c/h3\u003e\n\u003cp\u003eAll eyes underwent 25G or 23G PPV using the Constellation Vision System (Alcon, Fort Worth, TX). A non-contact wide-angle viewing system (Resight Fundus Imaging System, Carl Zeiss Meditec AG, Jena, Germany) was used, and all procedures were performed by a single surgeon (R.d\u0026rsquo;O.).\u003c/p\u003e \u003cp\u003eBefore vitrectomy, all phakic eyes underwent phacoemulsification and intraocular lens implantation using the same surgical platform. After standard PPV, all the eyes with BALAD-lamellar hole and two eyes with transition BALAD were subjected to staining of the ILM with trypan blue and Brilliant Blue G (Membraneblue-dual, DORC, Zuidland, The Netherlands). This was followed by peeling of the ILM for 360\u0026deg; at the macula and the creation of an inverted flap covering the hole at the time of RRD repair. No ILM flap insertion was performed in this series.\u003c/p\u003e \u003cp\u003eAt the end of surgery, 20% sulfur hexafluoride (SF6) gas or silicone oil (SO) with a viscosity of 1000 centistokes was used as an internal tamponade. Regardless of the tamponade agent and break location, all patients were strictly instructed to maintain a face-down position for 24 hours following the operation. The SO was removed within 3 months following PPV.\u003c/p\u003e \u003cdiv id=\"Sec5\" class=\"Section2\"\u003e \u003ch2\u003eStatistical analysis\u003c/h2\u003e \u003cp\u003eContinuous variables are presented as the mean\u0026thinsp;\u0026plusmn;\u0026thinsp;standard deviation, while categorical variables are presented as an absolute frequency and percentage. Comparisons of logMAR BCVA between subgroups were conducted using the Mann\u0026ndash;Whitney test.\u003c/p\u003e \u003cp\u003eComparisons between preoperative demographics characteristics, the integrity of external limiting membrane (ELM) and ellipsoid zone (EZ) and the restoration of foveal bulge, between the eyes with different forms of BALAD, were evaluated using the chi-squared test. Gwet\u0026rsquo;s AC1 coefficient was used to assess the agreement between graders. The results of multivariable regression analysis are presented as the mean difference\u0026thinsp;\u0026plusmn;\u0026thinsp;standard error with 95% confidence intervals (CIs) and \u003cem\u003eP\u003c/em\u003e-values. Pearson\u0026rsquo;s test was used to correlate the height of the cyst on the cavity BALAD with the BCVA recovery. The statistical analysis was performed using SAS v.9.4 TS Level 1M8 (SAS Institute Inc., Cary, NC, USA). \u003cem\u003eP\u003c/em\u003e-values\u0026thinsp;\u0026lt;\u0026thinsp;0.05 were considered statistically significant.\u003c/p\u003e \u003c/div\u003e"},{"header":"RESULTS","content":"\u003cp\u003eAmong the 42 patients included in the study, 25 (59.5%) were men with a mean age of 62.6 years (\u0026plusmn; 9.3 SD). Duration of central vision loss, according to patient perception, was 6.7 \u0026plusmn; 3.9 days, quadrants of detachment were 2.8 (\u0026plusmn;0.9), proliferative vitreo-retinopathy Retina Society grade \u003csup\u003e9\u003c/sup\u003e was 0 in 15, A in 18 and B in 9 eyes. \u0026nbsp;The RRD height measured at the fovea was 1668.1 \u0026plusmn; 553.4 \u0026micro;m.\u003c/p\u003e\n\u003cp\u003eCavity BALAD was found in 23 eyes (54.7%), BALAD-lamellar hole was found in 13 eyes (31%), and transition BALAD was found in\u0026nbsp;6 eyes\u0026nbsp;(14.2%). In eyes with cavity BALAD, the cavity had a variable height ranging from 23 to 410 \u0026micro;m (mean height\u0026nbsp;102.4 \u0026plusmn; 77.2 \u0026micro;m). The hole diameter in the eyes with transition and BALAD-lamellar hole measured 178.3 \u0026plusmn; 68.7 \u0026micro;m and 321.4 \u0026plusmn; 57.7 \u0026micro;m, respectively.\u003c/p\u003e\n\u003cp\u003eIndependently from the type of BALAD visible on OCT, all the eyes showed a sharp orange-red round area at the fovea corresponding to the cyst in cavity/transition BALAD eyes and to the open roof in BALAD-lamellar hole eyes. (\u003cstrong\u003eFig 2\u003c/strong\u003e)\u003c/p\u003e\n\u003cp\u003eTwenty-five eyes (59.5%) had images taken preoperatively at the time of RRD diagnosis and on the day of operation (mean interval between the two recordings: 3.2 \u0026plusmn; 1.4 and 3.6 \u0026plusmn; 0.9 days). Among these eyes, none with cavity or transition BALAD developed into BALAD-lamellar hole and none with BALAD-lamellar hole evolved into FTMH.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eAll the eyes underwent standard PPV. Two out of 6 eyes with transition BALAD and all the 13 eyes with BALAD-lamellar hole underwent additional ILM peeling and ILM cover flap.\u003c/p\u003e\n\u003cp\u003eAt the end of PPV procedure, 17 and 25 eyes received SF6 20% and SO as a tamponade, respectively.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003ePostoperatively, CFT progressively increased throughout the 12 months follow-up period: 1 month\u0026nbsp;136.4 \u0026micro;m \u0026plusmn; 73.3 \u0026micro;m; 3 months: 158.4 \u0026micro;m \u0026plusmn; 75.9 \u0026micro;m ; 6 months: 169.8 \u0026micro;m \u0026plusmn; 65.9 \u0026micro;m; 12 months: 177.4 \u0026micro;m \u0026plusmn; 61.5 \u0026micro;m. Progressive\u0026nbsp;increase of the CFT was significant in the cavity/transition BALAD group (month 1: 116.5 \u0026micro;m \u0026plusmn; 43.1 \u0026micro;m; month 12: 165.6 \u0026micro;m \u0026nbsp;\u0026plusmn; 48.6 \u0026micro;m, P= 0.006) but not in the BALAD-lamellar hole group (month 1: 212.3 \u0026micro;m \u0026plusmn; 95.9 \u0026micro;m; month 12: 229.4 \u0026micro;m \u0026plusmn; 92.7 \u0026micro;m, P=0.8) (\u003cstrong\u003eFig 3\u003c/strong\u003e). This result is likely related to the poor restoration of the retinal layers and to the thickness of the flap that remained stable over the course of follow-up.\u003c/p\u003e\n\u003cp\u003eAt 1 month postoperatively, only 4 (9.5%) eyes showed a continuous ELM, whereas EZ was discontinuous in all eyes. Twelve months post-operatively 29 (69%) and 23 (54.8%) eyes had recovered a continuous ELM and EZ respectively, with a significant difference between cavity/transition BALAD eyes and BALAD-lamellar hole eyes ( 82.7% vs. 38.5%, P=0.006 and 68.9% vs. 23%, P=0.004) \u003cstrong\u003e. (Table 1)\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAt 12 months, a visible foveal bulge was observed in 11 eyes (37.9%) with cavity/transition BALAD and in 2 eyes (15.4%) with preoperative BALAD-lamellar hole. \u003cstrong\u003e(Table 1,\u0026nbsp;\u003c/strong\u003e\u003cstrong\u003eFig 3\u003c/strong\u003e)\u003c/p\u003e\n\u003cp\u003eThere was very good inter-grader agreement for determining the integrity of EZ or ELM and the presence of foveal bulge between the two masked\u0026nbsp;readers, with Gwet\u0026rsquo;s AC1 coefficients of 0.85 (0.81 to 0.93), 0.89 (0.83 to 0.95), and 0.94 (0.90 to 0.0.97), respectively.\u003c/p\u003e\n\u003cp\u003ePreoperative BCVA was \u0026nbsp;2.0 \u0026plusmn; 0.8 \u0026nbsp;logMAR and significantly improved over the course of follow-up (1 month: 0.8 \u0026plusmn; 0.5), (3months: 0.5 \u0026plusmn; 0.3), (6 months: 0.4 \u0026plusmn; 0.2), 12 months: 0.3 \u0026plusmn; 0.2). LogMAR BCVA differed significantly between eyes with cavity/transition BALAD and those with BALAD-lamellar hole at all postoperative follow-up visits (0.8 \u0026plusmn; 0.4 vs. 1 \u0026plusmn; 0.6 at month 1 [\u003cem\u003eP=\u003c/em\u003e 0.025], 0.5 \u0026plusmn; 0.23 vs. 0.7 \u0026plusmn; 0.4 [\u003cem\u003eP=\u003c/em\u003e0.03] at month 3, 0.4 \u0026plusmn; 0.20 vs. 0.6 \u0026plusmn; 0.4 [\u003cem\u003eP=\u003c/em\u003e0.04] at month 6, 0.3 \u0026plusmn; 0.2 vs. 0.6 \u0026plusmn; 0.4 [\u003cem\u003eP=\u003c/em\u003e0.01] at month 12). The height of the cyst in cavity/transition BALAD\u0026nbsp;eyes was not associated with BCVA recovery at the 12-month follow-up.\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e"},{"header":"DISCUSSION","content":"\u003cp\u003eThis retrospective study shows that multicolor imaging is a useful imaging modality for detecting BALAD preoperatively, showing a sharp orange-red round area at the fovea. However, in contrast with OCT, multicolor imaging does not allow the clinician to resolve the three types of BALAD. Following standard PPV and retinal reattachment, in the eyes with cavity/transition BALAD, the BALAD resolved with no progression to BALAD lamellar-hole or FTMH. Peeling of the ILM with creation of an ILM inverted cover flap resulted in closure in BALAD-lamellar hole with no progression to FTMH. Over 12 months of follow-up, eyes with cavity/transition BALAD showed a better rate of restoration of the EZ and ELM bands and foveal bulge in comparison to eyes with BALAD-lamellar hole. Accordingly, BCVA remained significantly worse in the eyes with BALAD-lamellar hole in comparison to those with cavity/transition BALAD.\u003c/p\u003e \u003cp\u003eOriginally described by Metha et al.[\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e] and subsequently observed in various retinal diseases,[\u003cspan additionalcitationids=\"CR3\" citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e] BALAD has recently been reported in the context of RRD.[\u003cspan additionalcitationids=\"CR6\" citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e] In exudative processes, BALAD is hypothesized to occur when outwardly directed forces that support attachment of the photoreceptor OS to the RPE exceed the tensile strength of the photoreceptor IS myoid.[\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e] In RRD, the mechanism underlying BALAD formation is thought to be different. The influx of hypo-osmolar liquefied vitreous through an open break progressively detaches the neurosensory retina from the RPE and results in hydration of the outer retina with subsequent changes to the modulus of elasticity of the outer retina, which results in outer corrugations.[\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e] Because of its peculiar histological characteristics, particularly the rigid scaffold provided by the M\u0026uuml;ller cell cone, the outer fovea cannot corrugate. Thus, the stretching forces result in breakdown at the myoid level and formation of an intraretinal foveal cyst (cavity BALAD). More severe conditions cause complete disruption of the inner retinal layers with a bridge of photoreceptor remnants/IPM (BALAD-lamellar hole).\u003c/p\u003e \u003cp\u003eCavity BALAD and BALAD-lamellar hole are at the extremes of a spectrum of progressively increasing abnormalities that include cleavage planes extending from the IS myoid to the Henle fiber layer/ONL and thinning of the ONL as described by Melo et al. [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e, \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e] Thus, as expected, features typical of cavity and BALAD-lamellar hole, can be sometimes visible in the same eye and revealed by differently orientated or spaced apart OCT scans. We named these cases \u0026ldquo;transition BALAD\u0026rdquo;, since they may well represent a transient state in the process of evolution from cavity BALAD to BALAD-lamellar hole.\u003c/p\u003e \u003cp\u003eIdentifying BALAD preoperatively is important because, among the eyes with fovea-off RRD, those with BALAD will have a worse anatomical and functional prognosis. Reportedly, ophthalmoscopy and fundus camera do not show peculiar features in eyes with BALAD.[\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e, \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e] Conversely, as shown in this series, multicolor imaging may help to identify BALAD. In fact, multicolor imaging showed a sharp orange-red round area at the fovea in the eyes with BALAD, that corresponded either to the intraretinal cyst ( eyes with cavity/transition BALAD) or to the open roof ( eyes with BALAD-lamellar hole). The main difference between standard fundus cameras and cSLO multicolor device is that the latter combines images obtained by using three different monochromatic laser sources (blue reflectance: 488 nm; green reflectance: 515 nm and infrared reflectance: 820 nm). Such characteristic allows to visualize details at different retinal layers with a better resolution than fundus camera. As a consequence, in eyes with BALAD, the intraretinal cyst or the open foveal roof may result difficult to be detected on ophthalmoscopy or standard fundus photography but are clearly revealed by multicolor images.\u003c/p\u003e \u003cp\u003eHowever, the multicolor imaging cannot resolve the three types of BALAD we distinguished solely on the basis of OCT. Such differentiation is important to plan the optimal surgical approach when using PPV to repair the RRD since only a minority of BALAD-lamellar hole closes after routine PPV (and no ILM peel) with retinal reattachment.\u003c/p\u003e \u003cp\u003eIn fact, in a prospective series, Melo et al. reported that all eyes with persistent BALAD-lamellar hole following retinal reattachment with pneumatic retinopexy progressed to FTMH suggesting that the bridge of outer retinal tissue in BALAD-lamellar hole is non-viable tissue such as IPM.[\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e] In a subsequent retrospective series, the same group [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e] reported that 69% of eyes (20/29) with BALAD-lamellar hole developed into FTMH after RRD repair with pneumatic retinopexy or PPV without ILM peeling. Similarly, Fu et al.[\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e] reported that 67% of eyes with BALAD-lamellar hole evolved into FTMH after PPV without ILM peeling.\u003c/p\u003e \u003cp\u003eIn this study, the eyes with cavity BALAD underwent standard PPV and all the eyes with BALAD-lamellar hole had additional ILM peeling and ILM cover flap. After reattachment, none of the eyes showed evidence of FTMH. Regarding the eyes with transition BALAD, peeling of ILM was performed in 2 out of 6 eyes. After retinal reattachment none of the six eyes progressed to FTMH. Thus, it is likely that the eyes with transition BALAD, similarly to eyes with cavity BALAD, usually do not evolve to FTMH when RRD is repaired with standard PPV. Perhaps the residual intact inner retinal layers visible in eyes with transition BALAD may represent substantial viable tissue, with a smaller defect, ans also potentially serve as a significant scaffold that allows for anatomic restoration and does not result\u003c/p\u003e \u003cp\u003eIn the development of a FTMH. Thus, routine peeling of ILM in cases with transition BALAD is probably not warranted or even potentially detrimental since it might cause unintentional avulsion of the foveal residual inner layers.[\u003cspan additionalcitationids=\"CR13 CR14\" citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e]\u003c/p\u003e \u003cp\u003eConversely, ILM peeling at the time of RRD repair with PPV in eyes with BALAD-lamellar seems to successfully prevent FTMH formation. Similarly to what we found in the present study, Fu et al. [\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e] reported that 6 out of 7 eyes (85%) with BALAD-lamellar hole successfully closed after ILM peeling and ILM flap coverage performed concomitant with RRD repair using PPV. Similarly, the closure rate of FTMH developing from BALAD-lamellar hole and requiring subsequent PPV/ILM peeling, has been documented to be 80%. [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]\u003c/p\u003e \u003cp\u003eMelo et al.[\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e, \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e] suggested operating on eyes with BALAD in a timely manner since cavity BALAD may develop into BALAD-lamellar hole and ultimately into secondary FTMH.\u003c/p\u003e \u003cp\u003eIn the present series, no cases of cavity BALAD developed into BALAD-lamellar hole or FTMH after an average period of preoperative observation of 3.5 days. Similarly, Fu et al.[\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e] did not report evolution from cavity BALAD to BALAD-lamellar hole in their series. Thus, operating the eyes with BALAD within 3 days from presentation (as generally suggested for the management of non-BALAD fovea-off RRD [\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e, \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e]), seems to be reasonable. It is likely that, in addition to the duration of detachment, the extent to which the outer retinal hydration is occurring in a given detachment in a significant factor in the speed at which cavity BALAD will progress to BALAD lamellar hole. Indeed, previous studies [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e, \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e] reported that the height of detachment is the only variable significantly associated with the presence of BALAD. It is important to understand that BALAD in RRD and its subsequent sequelae are a relatively rapid degenerative process that occurs due to hydration-induced structural changes over weeks in untreated RRD.\u003c/p\u003e \u003cp\u003eAt 12 months postoperatively, overall 54.7% of the eyes showed continuity of the EZ, with significant differences between the cavity/transition and BALAD-lamellar hole groups (68.9% vs. 23%, P\u0026thinsp;=\u0026thinsp;0.004). These results are similar to those reported by Melo et al. [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e, \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e] in a prospective and a retrospective series (66% and 59% of patients who had OCT imaging at 1 year postoperatively, respectively) and in line with previous observations.[\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e]\u003c/p\u003e \u003cp\u003eInterestingly, the height of the cyst in cavity BALAD eyes did not correlate with BCVA recovery, which suggests that the split itself, rather than its thickness, is the main cause of photoreceptors damage. This is understandable as the height of the BALAD cavity may simply represent the accumulation of fluid in a potential space.\u003c/p\u003e \u003cp\u003eAs expected, LogMAR BCVA was significantly worse in BALAD-lamellar hole than in cavity/transition BALAD at all postoperative follow-up visits. [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e, \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e] This suggests that BALAD-lamellar hole cases portend a worse functional prognosis in comparison to cavity BALAD, possibly related to the more severe anatomical damage (disruption of the M\u0026uuml;ller cells cone and death of the central cones) observed in these eyes. Since all phakic eyes of this series had cataract extraction at the time of RRD repair surgery, the influence of the prevalence of cataract in the different groups and consequently on BCVA, can be excluded. We believe that BALAD-lamellar hole is an end-stage phase of the hydration induced degenerative change occurring to the fovea in dysregulated RRD.\u003c/p\u003e \u003cp\u003eThis study has various limitations. The small sample size and the retrospective design limit the strength of the conclusions that can be drawn from the data. Furthermore, all patients underwent PPV, a surgical technique that may negatively influence the morphological recovery of normal foveal features after RRD repair in comparison to pneumatic retinopexy or scleral buckling. A comparison between images taken at the time of RRD diagnosis and on the day of operation was available for only about 50% of the patients. Furthermore, the mean time interval between the two examinations was less than 4 days. Thus, the analysis of the possible preoperative development of cavity BALAD into BALAD-lamellar hole and FTMH was limited. Although none of the eyes with BALAD-lamellar hole developed FTMH after retinal reattachment, it remains uncertain whether the anatomical and functional recovery in eyes with BALAD-lamellar hole may be better if ILM peeling is performed concomitantly with RRD repair or at a later time, once the detachment has been repaired, such as would be the case with primary pneumatic retinopexy..\u003c/p\u003e \u003cp\u003eStrengths of this study include the preoperative role of multicolor imaging in addition to OCT for the identification and classification of the three types of BALAD. Furthermore this study suggests that although ILM peeling and cover flap are successful in achieving closure of BALAD-lamellar hole, these surgical manouvers are likely not warranted in eyes with transition BALAD. Thus, an accurate preoperative diagnosis is crucial to consider whether additional procedures (specifically peeling of ILM) at the time of RRD repair may be warranted. Finally, our results suggest that, although a timely intervention in eyes with BALAD is recommended, significant worsening within 3 days from original diagnosis is unlikely.\u003c/p\u003e \u003cp\u003eIn conclusion, this study highlights that multicolor imaging may help to diagnose BALAD preoperatively, but, in contrast with OCT, does not allow to resolve the different types of BALAD. Cavity and transition BALAD usually do not progress to BALAD-lamellar hole within 3 days from the diagnosis and do not develop into FTMH once the retina has been reattached. In the eyes with BALAD-lamellar hole, ILM peeling and ILM cover flap at the time of RRD repair successfully resulted in hole closure. Over 1 year of postoperative follow-up, restoration rates of integrity/continuity of the ELM/EZ bands/foveal bulge and BCVA remained lower in eyes with BALAD-lamellar hole in comparison to eyes with cavity/transition BALAD, which is expected in light of the advanced degenerative changes in BALAD lamellar-hole.\u003c/p\u003e"},{"header":"STATEMENTS AND DECLARATIONS","content":"\u003cp\u003e\u003cstrong\u003eAcknowledgments\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors thank the clinical investigator Gerarda Bruno for collecting data and caring for study patients.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding:\u003c/strong\u003e This project was supported in part with funding from Next Generation EU, [DM 155711.10.2022].\u003c/p\u003e\n\u003cp\u003eThis project was supported in part with funding from Next Generation EU, in the context of the National Recovery and Resilience Plan for Italy, Rome. \u0026nbsp; Investment PE8-Project Age-It: \u0026ldquo;Ageing well in an Ageing Society\u0026rdquo; [DM 155711.10.2022]. The funding organization had no role in the design or conduct of this research.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFinancial interests:\u0026nbsp;\u003c/strong\u003enone.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConflict of Interest:\u003c/strong\u003e The authors declare they have no financial interests.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eMehta N, Chong J, Tsui E, Duncan JL, Curcio CA, Freund KB, Modi Y (2021) Presumed foveal bacillary layer detachment in a patient with toxoplasmosis chorioretinitis and pachychoroid disease. Retin Cases Brief Rep 15: 391\u0026ndash;398. https://doi.org/10.1097/ICB.0000000000000817\u003c/li\u003e\n\u003cli\u003eAgarwal A, Freund KB, Kumar A, Aggarwal K, Sharma D, Katoch D, Bansal R, Gupta V, OCTA Study Group (2021) Bacillary layer detachment in Acute Vogt-Koyanagi-Harada Disease: a novel swept-source optical coherence tomography analysis. 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Retina 41: 2193-2207. https://doi.org/10.1097/IAE.0000000000003217\u003c/li\u003e\n\u003cli\u003eMuni RH, Darabad MN, Oquendo PL, Hamli H, Lee WW, Nagel F, Bansal A, Melo IM, Ramachandran A (2023) Outer retinal corrugations in rhegmatogenous retinal detachment: the retinal pigment epithelium-photoreceptor dysregulation theory. Am J Ophthalmol 245: 14\u0026ndash;24. https://doi.org/10.1016/j.ajo.2022.08.019\u003c/li\u003e\n\u003cli\u003eHisatomi T, Tachibana T, Notomi S, Nakatake S, Fujiwara K, Murakami Y, Ikeda Y, Yoshida S, Enaida H, Murata T, Sakamoto T, Sonoda KH, Ishibashi T (2017) Incomplete repair of retinal structure after vitrectomy with internal limiting membrane peeling. Retina 37: 1523-1528. https://doi.org/10.1097/IAE.0000000000001388.\u003c/li\u003e\n\u003cli\u003eFoveau P, Leroy B, Berrod JP, Conart JB (2018) Internal limiting membrane peeling in macula-off retinal detachment complicated by Grade B Proliferative Vitreoretinopathy. Am J Ophthalmol 191:1-6. https://doi.org/10.1016/j.ajo.2018.03.037\u003c/li\u003e\n\u003cli\u003eSadeghi E, Colorado-Zavala MF, Almuhtaseb H, Venkatesh R, Parolini B, Chhablani J (2025) Anatomical and functional changes after internal limiting membrane peeling. Surv Ophthalmol 70: 357-368. https://doi.org/10.1016/j.survophthal.2025.01.008\u003c/li\u003e\n\u003cli\u003eTao J, Yang J, Wu Y, Ye X, Zhang Y, Mao J, Wang J, Chen Y, Shen L (2022) Internal limiting membrane peeling distorts the retinal layers and induces scotoma formation in the perifoveal temporal macula. Retina 42: 2276-2283. https://doi.org/10.1097/IAE.0000000000003619\u003c/li\u003e\n\u003cli\u003eYee C, Xu DN, Berger RF, Traustason KE, Flaxel C (2022) Visual outcomes in macula-involving retinal detachments based on time to surgical repair. Ophthalmic Surg Lasers Imaging Retina 53: 439-444. https://doi.org/10.3928/23258160-20220723-02\u003c/li\u003e\n\u003cli\u003eMiyake M, Nakao SY, Morino K, Yasukura S, Mori Y, Ishihara K, Muraoka Y, Miyata M, Tamura H, Sakamoto T, Tsujikawa A; Japan-Retinal Detachment Registry Group (2023) Effect of duration of macular detachment on visual prognosis after surgery for macula-off retinal detachment: Japan-retinal detachment registry. Ophthalmol Retina 7: 375-382. https://doi.org/10.1016/j.oret.2023.01.014\u003c/li\u003e\n\u003cli\u003edell\u0026apos;Omo R, Viggiano D, Giorgio D, Filippelli M, Di Iorio R, Calo\u0026apos; R, Cardone M, Rinaldi M, dell\u0026apos;Omo E, Costagliola C (2015) Restoration of foveal thickness and architecture after macula- off retinal detachment repair. Invest Ophthalmol Vis Sci 56:1040\u0026ndash;1050. https://doi.org/10.1167/iovs.14-15633\u003c/li\u003e\n\u003c/ol\u003e"},{"header":"Table","content":"\u003cp\u003e\u003cstrong\u003eTable 1.\u003c/strong\u003e Restoration of continuos ellipsoid zone, external limiting membrane and foveal bulge in eyes with cavity/transition bacillary layer detachment (BALAD) and BALAD-lamellar hole over 12 months of follow-up.\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"726\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"4\" valign=\"top\" style=\"width: 274px;\"\u003e\n \u003cp\u003e\u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;\u003cstrong\u003eContinuous EZ\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"3\" valign=\"top\" style=\"width: 227px;\"\u003e\n \u003cp\u003e\u003cstrong\u003eContinuous ELM\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"3\" valign=\"top\" style=\"width: 226px;\"\u003e\n \u003cp\u003e\u003cstrong\u003ePresence of foveal bulge\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 54px;\"\u003e\n \u003cp\u003ePost-op\u003c/p\u003e\n \u003cp\u003efollow-up\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003eCavity/transition BALAD\u003c/p\u003e\n \u003cp\u003en=29 eyes\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 65px;\"\u003e\n \u003cp\u003eBALAD-lamellar hole\u003c/p\u003e\n \u003cp\u003en=13 eyes\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 51px;\"\u003e\n \u003cp\u003eP\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003eCavity/transition BALAD\u003c/p\u003e\n \u003cp\u003en=29 eyes\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 65px;\"\u003e\n \u003cp\u003eBALAD-lamellar hole\u003c/p\u003e\n \u003cp\u003en=13 eyes\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 58px;\"\u003e\n \u003cp\u003eP\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003eCavity/transition BALAD\u003c/p\u003e\n \u003cp\u003en=29 eyes\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 74px;\"\u003e\n \u003cp\u003eBALAD-lamellar hole\u003c/p\u003e\n \u003cp\u003en=13 eyes\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 47px;\"\u003e\n \u003cp\u003eP\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 54px;\"\u003e\n \u003cp\u003e1 mo.\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e0 (0%)\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 65px;\"\u003e\n \u003cp\u003e0 (0%)\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 51px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e-\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e4 (13.8%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 65px;\"\u003e\n \u003cp\u003e0 (0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 58px;\"\u003e\n \u003cp\u003e0.02*\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e0 (0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 74px;\"\u003e\n \u003cp\u003e0 (0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 47px;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 54px;\"\u003e\n \u003cp\u003e3 mo\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e9 (31%)\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 65px;\"\u003e\n \u003cp\u003e0 (0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 51px;\"\u003e\n \u003cp\u003e0.009*\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e13 (44.8%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 65px;\"\u003e\n \u003cp\u003e0 (0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 58px;\"\u003e\n \u003cp\u003e0.0001*\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e0 (0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 74px;\"\u003e\n \u003cp\u003e0 (0%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 47px;\"\u003e\n \u003cp\u003e-\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 54px;\"\u003e\n \u003cp\u003e6 mo\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e16 (55.2%)\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 65px;\"\u003e\n \u003cp\u003e1 (7.7%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 51px;\"\u003e\n \u003cp\u003e0.007*\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e22 (75.8%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 65px;\"\u003e\n \u003cp\u003e3 (23.1%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 58px;\"\u003e\n \u003cp\u003e0.006*\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e6 (20.7%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 74px;\"\u003e\n \u003cp\u003e1 (7.7%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 47px;\"\u003e\n \u003cp\u003e0.03*\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 54px;\"\u003e\n \u003cp\u003e12 mo\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e20 (68.9%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 65px;\"\u003e\n \u003cp\u003e3 (23%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 51px;\"\u003e\n \u003cp\u003e0.004*\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e24 (82.7%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 65px;\"\u003e\n \u003cp\u003e5 (38.5%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 58px;\"\u003e\n \u003cp\u003e0.006*\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e11 (37.9%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 74px;\"\u003e\n \u003cp\u003e2 (15,4%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 47px;\"\u003e\n \u003cp\u003e0.04*\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e* statistical significance.\u003c/p\u003e\n\u003cp\u003eEXL= external limiting membrane; EZ=ellipsoid zone; BALAD= bacillary layer detachment; mo= months; post-op= postoperative.\u003c/p\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"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":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Bacillary layer detachment, optical coherence tomography, multicolor imaging, confocal scanning laser ophthalmoscope, rhegmatogenous retinal detachment","lastPublishedDoi":"10.21203/rs.3.rs-9187269/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-9187269/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003ePurpose:\u003c/strong\u003e To describe the preoperative and postoperative features of eyes with rhegmatogenous retinal detachment (RRD) and different types of bacillary layer detachment (BALAD).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMethods\u003c/strong\u003e\u003cem\u003e\u003cstrong\u003e:\u003c/strong\u003e\u003c/em\u003e Retrospective cohort study of\u003cem\u003e\u003cstrong\u003e \u003c/strong\u003e\u003c/em\u003epatients with primary fovea-off RRD and BALAD who underwent pars plana vitrectomy (PPV). Optical coherence tomography, multicolor images, and logarithm of the minimum angle of resolution (logMAR) best-corrected visual acuities (BCVAs) were obtained preoperatively and at 1, 3, 6, and 12 months after the operation. Three types of BALAD were identified preoperatively on the basis of OCT: cavity, transition and lamellar hole.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eResults:\u003c/strong\u003e, among the 42 eyes included, 23 were classified as cavity, 6 as transition and 13 as lamellar hole. All types showed a sharp red round area at the fovea on multicolor images. After standard PPV, additional internal limiting membrane (ILM) peeling was carried out in none eyes with cavity, in 2 eyes with transition and in all BALAD-lamellar hole eyes. Post-operatively, no eyes showed evidence of full-thickness macular hole (FTMH). At 12 months post-operatively, ellipsoid zone (EZ) and external limiting membrane (ELM) appeared continuous in 54.8% (23/42) eyes (20 cavity/transition and 3 BALAD lamellar-hole, P=0.004) and 69% (29/42) eyes (24 cavity/transition and 5 BALAD lamellar-hole, P= 0.006), respectively. Accordingly, BCVA was worse in the eyes with BALAD-lamellar hole than in those with cavity/transition BALAD (0.6 ± 0.4 vs. 0.3 ± 0.2; \u003cem\u003eP=\u003c/em\u003e0.01).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConclusion:\u003c/strong\u003e multicolor imaging is useful to identify BALAD. Cavity and transition BALAD are likely to not progress to FTMH after retinal reattachment. ILM peeling and cover flap prevented FTMH formation in eyes with BALAD-lamellar hole in this cohort. 12 months postoperatively, restoration rates of integrity of ELM and EZ bands and BCVA scores remained lower in eyes with BALAD-lamellar hole in comparison to those with cavity/transition BALAD.\u003c/p\u003e","manuscriptTitle":"Identification and management of different types of bacillary layer detachment in eyes with rhegmatogenous retinal detachment","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-04-09 16:40:04","doi":"10.21203/rs.3.rs-9187269/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"ee5efc6f-401f-4a20-b9ab-ac9826b8e806","owner":[],"postedDate":"April 9th, 2026","published":true,"recentEditorialEvents":[{"type":"editorInvitedReview","content":"","date":"2026-05-05T20:55:25+00:00","index":27,"fulltext":""},{"type":"reviewerAgreed","content":"167228885043427110046199424202386789381","date":"2026-05-05T06:37:59+00:00","index":26,"fulltext":""}],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2026-04-09T16:40:08+00:00","versionOfRecord":[],"versionCreatedAt":"2026-04-09 16:40:04","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-9187269","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-9187269","identity":"rs-9187269","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}