Evaluation of biometric indicators of anterior segment parameters after ICL implantation by swept-source optical coherence tomography

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To evaluate the anterior segment structure alteration after implantable collamer lens (ICL) implantation in myopic patients using swept-source quantitative optical coherence tomography (SS-OCT). Methods. This prospective study included 47 eyes of 24 patients with preoperative spherical equivalent ≥ -3.00 D. Patients underwent ICL implantation at Department of Ophthalmology, Peking University Third Hospital, from May 2021 to December 2022. SS-OCT was used to measure biometry including anterior chamber width (ACW), angle opening distance (AOD), angle recess area (ARA), trabecular iris area (TISA), trabecular-iris angle (TIA), iridotrabecular contact (ITC) area and ITC Index before ICL implantation surgery and at 1 month follow-up. Results. At one month following ICL implantation, the ITC area is 0.396 ± 0.37 mm 2 , and the ITC index is 8.143 ± 5.439 %. All angle parameters, with the exception of ACW, showed a statistically significant reduction on SS-OCT (P<0.05). Mean AOD500, AOD750, ARA500, ARA750, TISA500, TISA750, TIA500 and TIA750 values at one month postoperatively declined by 60.0%, 60.4%, 58.1%, 59.2%, 57.3%, 58.7%, 48.8% and 50.7%, respectively. Vault was positively correlated with ITC index and the percent change in anterior chamber parameters. The vault of >0.659mm was found to be optimal for angle-closure suspect with a sensitivity of 85.2% and a specificity of 53.9%. Conclusions. Anterior chamber parameters decreased 1 month after ICL implantation, and their percentage changes and ITC index correlated with the vault. When the vault is larger than 0.659mm, it is necessary to be alert to possible closed angle suspicion. implantable collamer lens implantation surgery myopia optical coherence tomography vault iridotrabecular contact Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Introduction Uncorrected refractive error is the third leading cause of blindness and the first cause of moderate to severe visual impairment worldwide[ 1 ]. Myopia is the most common type of refractive error, and uncorrected myopia costs hundreds of billions of dollars in lost productivity worldwide each year[ 2 ]. The global prevalence of myopia has reached 1.406 billion people (22.9% of the global population), while about 80%-90% of 18-year-olds in East Asia are myopic and 10%-20% have high myopia. It is estimated that by 2050, 4.758 billion people will have myopia (49.8% of the global population) and 938 million people will have high myopia (9.8% of the global population)[ 3 , 4 ]. As a kind of intraocular refractive surgery, implantable collamer lens (ICL; Staar Surgical, Nidau, Switzerland) implantation has been widely affirmed for its safety and effectiveness in correcting moderate and high myopia[ 5 , 6 ]. However, the intraocular lens is implanted into the posterior ciliary sulcus in the ICL implantation operation, which has a particular impact on the anatomical structure of the anterior segment and may affect the drainage of aqueous humor due to the reduction or closure of the anterior chamber angle (ACA), resulting in elevated eye pressure or secondary glaucoma[ 7 – 9 ]. Anterior segment optical coherence tomography (AS-OCT) is a new, non-invasive, high-resolution, cross-sectional imaging technique with broad application potential for the anterior segment. Swept-source OCT (SS-OCT, CASIA SS-1000; Tomey, Nagoya, Japan) is a type of AS-OCT which performs 128 meridional scans and analysis with high-speed A-scan in 2.4 seconds for 360° ACA[ 10 ]. Its in-built software can be used to determine the degree of 360° iridotrabecular contact area (ITC area) and calculate the ITC index. The anterior chamber depth (ACD) becomes shallower and the ACA becomes narrower after ICL implantation, which increases the risk of peripheral anterior synechia. SS-OCT parameters, including ITC index, may characterise the extent of angle closure and other biometric parameters that reflect mechanical obstruction of the aqueous outflow pathway. Therefore, this study aims to investigate the correlation between ITC index and anterior chamber parameters, angle parameters, vault, and intraocular pressure after ICL implantation, and whether it can be used as an indicator to evaluate the risk of angle closure glaucoma. Materials And Methods Participants This study included a total of 47 eyes from 24 participants with moderate and high myopia. All subjects underwent ICL implantation surgery at the Department of Ophthalmology, Peking University Third Hospital between May 2021 and December 2022. Inclusion criteria: 21 to 45 years old, with a spherical equivalent (SE) of greater than − 3.00 diopters (D), ACD ≥ 2.8mm, corneal endothelial cell count (cECC) ≥ 2000 cells/mm 2 , SE remained unchanged for more than 1 year, unsatisfactory vision with contact lenses or spectacles. All patients included in this study had no history of intraocular surgery and showed no other ocular pathologies (uveitis, glaucoma, cataract, keratoconus, severe dry eye, etc.) or serious systemic diseases (diabetes, uncontrolled hypertension, severe hyperthyroidism, etc.). The method of this study was approved by the Ethics Committee of Peking University Third Hospital (M2020240). In addition, this study was registered and approved on Clinical Trials.gov on 23/06/2020 (registration number: NCT04443231). Each subject was given informed consent after an adequate study explanation. Before surgery, each subject got a full ocular examination: the horizontal white-to-white (WTW) distance and axial length (AL) were measured by optical biometry (IOL Master 700; Carl Zeiss Meditec, Jena, Germany), cECC was obtained from each eye, using corneal endothelial microscope (SP-2000; Topcon, Tokyo, Japan). Additionally, each eye was subjected to slit-lamp biomicroscopic examination, corneal topography and funduscopic examination. Moreover, each patient's eye was assessed for uncorrected visual acuity (UCVA), best corrected visual acuity (BCVA), intraocular pressure (IOP), and manifest refraction before surgery as well as one month afterward. For statistical analysis, the decimal Snellen evaluation of UCVA and BCVA was converted to the logarithm of the minimum angle of resolution (logMAR). With the aid of a non-contact tonometer (CT-80; Topcon, Tokyo, Japan), the IOP was measured. The central vault of the ICL (distance from the posterior surface of ICL to the crystalline lens) was measured using AS-OCT one month after surgery. The size of the ICL was calculated with a STAAR sizing formula, based on the result of WTW and ACD. Myopic patients are planned for standard ICL implantation surgeries by the same surgeon (HQ) under similar settings. Preoperatively, in all patients, topical anesthesia (4% lidocaine) was administered 30 minutes before the operation. Through a 3.0-mm temporal corneal incision, the ICL was slowly inserted into the anterior chamber following the implantation of hyaluronic acid (ViscAid, Beijing, China)., under visualization with OPMI Lumera 700 surgical microscope (Carl Zeiss Meditec, Germany), and the Toric ICL implantation surgery was completed with the help of the Callisto Eye System (Carl Zeiss Meditec, Germany). Any remaining viscosurgical device was washed out of the anterior chamber with balanced salt solution. Antibiotic eye drops, steroidal eye drops and artificial tear drops were used postoperatively. Swept-source optical coherence tomography All subjects underwent SS-OCT imaging before any contact procedure. The subject takes the sitting position, places the chin on the chin rest, and adjusts the position of the eyes until the subject can see the scanning direction of the aiming light. The operator adjusts the area of the eye visible in the iris viewport until the iris is in sharp focus, then uses the controls to make coarse adjustments and moves the jaw rest until the corneoscleral junction is in view. Finally, the scleral spur (SS) was noted in each scan by a single observer with the relevant experience and training who was blinded to the gonioscopic findings. The quantitative parameters of SS-OCT are represented as follows (Fig. 1 ): (1) Anterior Chamber Width (ACW): the distance between the two SS in the OCT scan image. (2) Angle Opening Distance (AOD): The trabecular mesh at 500 µm away from the SS is drawn as a vertical line perpendicular to the posterior surface of the cornea and intersects with the iris. The distance between the two points is AOD500; the trabecular mesh at 750 µm away from the SS draws a vertical line perpendicular to the posterior surface of the cornea and intersects with the iris. The distance between the two points is AOD750. (3) Angle Recess Area (ARA): ARA500 is the triangular area bounded by AOD500 (the base) and angle recess (the apex); the triangular area bounded by AOD750 (the base) and angle recess (the apex) is ARA750. (4) Trabecular Iris Area (TISA): TISA500 refers to the area enclosed by the anterior surface of the iris, AOD500, a line drawn from the SS perpendicular to the plane of the inner scleral wall to the opposing iris and the posterior surface of the cornea; TISA750 refers to the area enclosed by the anterior surface of the iris, AOD750, a line drawn from the SS perpendicular to the plane of the inner scleral wall to the opposing iris and the posterior surface of the cornea. (5) Trabecular-Iris Angle (TIA): The angle between the two endpoints of AOD500 and the line connecting the angle recess is TIA500, and the angle between the two ends of AOD750 and the line connecting the angle recess is TIA750. (6) Iridotrabecular Contact Area (ITC Area): Contact area between the iris and angle wall anterior to the SS. (7) Iridotrabecular Contact Index (ITC index): The inbuilt semiautomated software of the CASIA can be used to measure the ITC index, which is a quantitative measure of the extent of angle closure across 360° of the angles expressed as a percentage (Fig. 2 ). The ITC analysis uses the anterior segment cross-sectional meridional images to determine the extent of contact between the iris and angle wall[ 10 ]. Statistical Analysis SPSS Statistics 26.0 (IBM, Chicago, IL) and R Version 4.2.2 were used to conduct all statistical analyses. The normality of data distributions was assessed using the Shapiro–Wilk test. All descriptive statistics were summarized and displayed as the mean ± standard deviation. Continuous variables and normal distribution data were compared using independent sample t tests. In addition, continuous variables that not normally distributed were compared by using the Mann–Whitney U test. Correlation between different parameters was studied by Pearson or Spearman rank correlation. Receiver operating characteristic (ROC) analysis was used to explore the ability of the vault for identifying eyes with angle-closure suspect. P < 0.05 was considered to be statistical significance. Results Demographics of the enrolled subjects are summarized in Table 1 . Preoperative demographics of the myopic patients underwent ICL implantation in this study. Mean patient age at the time of surgery was 28.33 ± 5.58 years (ranges from 21 years to 42 years). The preoperative manifest refraction spherical equivalent (MRSE) was − 7.66 ± 3.11 (ranges from − 3.50 D to -15.00D). The preoperative manifest sphere was − 7.24 D ± 3.03 D (ranges from − 3.00 D to − 14.25 D). The preoperative manifest refractive cylinder was − 0.84 ± 0.52 D (ranges from 0.00 to − 2.50 D). The AL was 26.32 ± 1.55 mm (ranges from 24.40 mm to 28.82 mm). WTW was 11.85 ± 0.24 mm (ranges from 11.3 mm to 12.3 mm). ACD was 3.23 ± 0.22 mm (ranges from 2.89 mm to 3.76mm). Table 1 Preoperative demographics of the myopic patients underwent implantable collamer lens implantation in this study Characteristic Mean ± SD Number, people/eyes 24/47 Sex, male/female 4/20 Age (years) 28.33 ± 5.58 (range 21 to 42) MRSE (D) −7.66 ± 3.11(range − 3.50 to -15.00) LogMAR BCVA 0.006 ± 0.019 AL (mm) 26.32 ± 1.55 WTW (mm) 11.85 ± 0.24 ACD (mm) 3.23 ± 0.22 cECC ( \(\text{c}\text{e}\text{l}\text{l}\text{s}/{\text{mm}}^{\text{2}}\) ) 2903.73 ± 272.03 ICL size (mm) 12.6 ± 0.28 ICL power (D) -8.19 ± 3.45 (range − 4.00 to -15.50) MRSE, manifest refraction spherical equivalent; LogMAR, logarithm of the minimal angle of resolution; BCVA, best corrected visual acuity; AL, axial length; WTW, white-to-white; ACD, anterior chamber depth; cECC, corneal endothelial cell count All surgical procedures were uneventful, and no postoperative complications, such as cataract formation, pigment dispersion syndrome, pupillary block, or axis rotation, were seen throughout the observation period. Visual acuity improved for all patients on the first day after surgery. One month postoperatively, only one eye (2.13%) lost one line of vision and 46 eyes (97.87%) maintained or gained BCVA (Fig. 3 A). The efficacy index was 1.06 ± 0.0.09 (preoperative BCVA: 0.006 ± 0.019 logMAR and postoperative UCVA: -0.0015 ± 0.0032 logMAR, P 0.05; Fig. 3 C) were not significantly different. At one month postoperatively, 91% and 100% were within ± 0.50 and 1.00 D of the attempted correction, respectively (Fig. 3 D). Iridotrabecular Contact and Anterior Segment SS-OCT Parameters were assessed at baseline and one month postoperatively (Table 2 ). At one month following ICL implantation, the vault is 0.519 ± 0.244 mm, the ITC area is 0.396 ± 0.37 mm 2 , and the ITC index is 8.143 ± 5.439%. All angle parameters, with the exception of ACW, showed a statistically significant reduction on SS-OCT (P < 0.05). Mean AOD500, AOD750, ARA500, ARA750, TISA500, TISA750, TIA500 and TIA750 values at one month postoperatively declined by 60.0%, 60.4%, 58.1%, 59.2%, 57.3%, 58.7%, 48.8% and 50.7%, respectively. Table 2 Iridotrabecular Contact and Anterior Segment SS-OCT Parameters of ICL patients pre- and postsurgery (Mean ± SD) Presurgery Postsurgery ACW (mm) Horizontal 11.663 ± 0.282 11.747 ± 0.298 Vertical 12.004 ± 0.369 11.927 ± 0.361 Average 11.889 ± 0.289 11.837 ± 0.305 AOD500 (mm) Nasal 0.754 ± 0.286 0.271 ± 0.095* Temporal 0.853 ± 0.398 0.294 ± 0.102* Superior 0.675 ± 0.343 0.25 ± 0.091* Inferior 0.798 ± 0.372 0.297 ± 0.093* Average 0.77 ± 0.316 0.278 ± 0.077* AOD750 (mm) Nasal 0.979 ± 0.291 0.346 ± 0.128* Temporal 1.087 ± 0.409 0.385 ± 0.133* Superior 0.905 ± 0.377 0.333 ± 0.113* Inferior 1.013 ± 0.378 0.396 ± 0.122* Average 0.996 ± 0.332 0.365 ± 0.105* ARA500 (mm 2 ) Nasal 0.273 ± 0.13 0.105 ± 0.041* Temporal 0.346 ± 0.253 0.116 ± 0.048* Superior 0.237 ± 0.144 0.093 ± 0.044* Inferior 0.325 ± 0.201 0.114 ± 0.04* Average 0.295 ± 0.152 0.107 ± 0.031* ARA750 (mm 2 ) Nasal 0.487 ± 0.195 0.182 ± 0.068* Temporal 0.581 ± 0.35 0.199 ± 0.076* Superior 0.434 ± 0.226 0.163 ± 0.072* Inferior 0.546 ± 0.292 0.201 ± 0.063* Average 0.512 ± 0.231 0.187 ± 0.055* TISA500 (mm 2 ) Nasal 0.255 ± 0.115 0.1 ± 0.037* Temporal 0.306 ± 0.187 0.111 ± 0.042* Superior 0.226 ± 0.135 0.089 ± 0.039* Inferior 0.292 ± 0.165 0.107 ± 0.036* Average 0.27 ± 0.129 0.102 ± 0.028* TISA750 (mm 2 ) Nasal 0.47 ± 0.183 0.177 ± 0.065* Temporal 0.542 ± 0.286 0.194 ± 0.07* Superior 0.423 ± 0.218 0.159 ± 0.067* Inferior 0.513 ± 0.258 0.195 ± 0.059* Average 0.487 ± 0.208 0.181 ± 0.052* TIA500 (deg.) Nasal 60.594 ± 15.948 29.578 ± 12.842* Temporal 59.531 ± 16.145 30.356 ± 10.016* Superior 58.006 ± 24.231 26.778 ± 7.351* Inferior 58.541 ± 20.916 28.453 ± 7.758* Average 59.168 ± 16.755 28.791 ± 6.944* TIA750 (deg.) Nasal 55.352 ± 12.355 24.948 ± 8.901* Temporal 55.018 ± 12.908 27.179 ± 8.8* Superior 53.733 ± 20.866 24.573 ± 6.277* Inferior 54.309 ± 16.465 26.212 ± 6.909* Average 54.603 ± 13.886 25.728 ± 6.237* ITC area (mm 2 ) 0.396 ± 0.37 ITC index (%) 8.143 ± 5.439 Vault (mm) 0.519 ± 0.244 ACW, anterior chamber width; AOD, angle opening distance; ARA, angle recess area; TISA, trabecular iris area; TIA, trabecular-iris angle; ITC, iridotrabecular contact. * P < 0.05 versus preoperative. Correlation analysis examining the relationships between ITC parameters and other factors were conducted next. The ITC index was positively correlated with the vault one month after ICL implantation, but no relationship was found between the ITC index and IOP, angle parameters and the percentage change of angle parameters. However, the vault value after ICL implantation was significantly positively correlated with the percentage change of angle parameters such as AOD500, AOD750, ARA500, ARA750, TISA500, TISA750, TIA500 and TIA750(Fig. 4 ). Receiver operating characteristic curves, with calculations of area under the curve (AUC) and 95% confidence intervals (CIs), were used to assess the performance of the vault for identifying eyes with angle-closure suspect, taking the ITC index ≥ 10.76% as the reference standard (Fig. 5 ). The AUC was 0.73 (95% CI, 0.56–0.90, P ༜0.05). The vault of > 0.659mm was found to be optimal for angle-closure suspect with a sensitivity of 85.2% (95% CI, 67.5–94.1) and a specificity of 53.9% (95% CI, 29.1–76.8). Discussion ICL implantation is one of the important means of correcting myopia at present. Compared with corneal refractive surgery, ICL implantation has good safety, stability and reversibility[ 11 , 12 ]. It does not cut the cornea while retaining the accommodation of its lens. The latest generation of ICL V4c drains aqueous humor through the central hole, thus solving the shortcomings of traditional ICL surgery that requires peripheral iridectomy and reduces the damage to ocular structure. Many studies have proved that ICL implantation can effectively improve patients' postoperative visual acuity and visual quality[ 13 , 14 ]. According to our data, ICL implantation is a safe and effective treatment for myopia. There were no postoperative complications throughout the observation period and the efficacy index was 1.06 ± 0.0.09. No eye loses two or more lines of vision after ICL implantation. All eyes were within ± 1.00 D of the attempted correction and 91% of eyes were within ± 0.50 D of the attempted correction. However, when the ICL is implanted in the eye, the loop foot is fixed in the ciliary sulcus of the posterior chamber, which inevitably contacts the posterior surface of the iris. Therefore, the examination of the structure of the chamber angle is very important for the safety after ICL implantation. In this work, SS-OCT was primarily used to examine the angle parameters following ICL implantation. At present, the commonly used equipment for observing the chamber angle includes gonioscopy, ultrasound biomicroscope (UBM), Pentacam anterior segment analysis system and OCT[ 15 ]. Gonioscopy and UBM are contact examinations, which are not suitable for patients in the early postoperative period, and the measurement results depend on the technique and subjective judgment of clinicians. Pentacam uses a Scheimflug camera to scan and shoot, which cannot directly visualize the angle structure since visible light cannot penetrate deep into the tissue. The SS-OCT used in this study is a non-contact rapid anterior segment imaging device with fast imaging speed, high resolution, and good signal-to-noise ratio. It can automatically analyze the image and obtain the position of the scleral protrusion and the angle recess, obtain parameters such as AOD, ARA, TISA, TIA and the proprietary ITC index, and conduct a full-automatic analysis and statistics of the opening and closing of the chamber angle. The ACA is an important basis for evaluating the risk factors of glaucoma and the changes of the anterior segment. In 2001, Abela-Formanek et al.[ 16 ] first used gonioscopy to observe that about 58% of eyes with ACA less than 20 degrees after ICL implantation. Fernández-Vigo et al.[ 17 ] reported in 2017 that ACA decreased by 39%-45% in 1 month after ICL V4c implantation using FD-OCT, and remained stable for the next 2 years. Liu et al.[ 18 ] used SS-OCT to observe that AOD500, TISA500, and TIA500 decreased by 65.4%-71%, 64.1%-69.3%, and 53.8%-61.5% after ICL V4c implantation. Therefore, we evaluate the ACA alteration at 1 month after ICL implantation in myopic patients using SS-OCT. The reductions in ACA parameters observed in our study were similar to those in previous reports. We also found that vault was positively correlated with the percent change in anterior chamber parameters including ACA, but not anterior chamber parameters after ICL implantation. According to Shaffer's classification, if the ACA is greater than 20°, there is no potential for angle closure; if the angle is narrower than 20°, there is a risk of angle closure. Therefore, combined with the changes in ACA before and after ICL surgery, when the ACA before ICL implantation is less than 40° or less than 20° after surgery, or when the vault is high, we should be alert to the risk of ACA closure or glaucoma after surgery. The inter- and intra-observer agreement of the ITC index for measuring the degree of angle closure using SS-OCT has been reported to be good[ 19 , 20 ]. The index had moderate agreement and good diagnostic performance for angle-closure with gonioscopy as the reference standard with a sensitivity of 71.9% and specificity of 84.3%[ 21 ]. We found that the ITC index was only positively correlated with the vault after ICL implantation, but not with the postoperative angle parameters or the percentage change of angle parameters. In this study, the highest vault was 1.201 mm and the highest ITC index was 22.2% 1 month after ICL implantation. In all study subjects, no significant increase in IOP or glaucoma was found after surgery, which may be related to the change of anatomical angle earlier than the change of IOP or the degree of angle closure has not decreased below the anatomical threshold[ 22 ]. Greater ITC could be a biomarker of a higher IOP and greater visual field loss[ 23 ]. In evaluating the ITC index in the primary angle-closure disease population, Barkha et al.[ 24 ] found that the ITC index in the primary angle-closure suspect, primary angle closure and primary angle-closure glaucoma groups were 10.76%, 28.53%, and 81.43%, respectively. In this study, therefore, we further employed ROC curves in an effort to identify the performance of the vault for identifying eyes with angle-closure suspect. We found the vault of > 0.659mm was optimal for eyes with angle-closure suspect with a sensitivity of 85.2% and a specificity of 53.9%, which was lower than the upper limit of optimal vault recommended by Starr Surgical. Indeed, Asian, female eyes are thought to have a genetic and anatomic predisposition to develop angle closure[ 25 , 26 ]. When the intraocular lens was placed in the ciliary sulcus, its posterior “pushing” mechanism on the iris resulted in secondary angle closure and peripheral iris obstruction, impeding aqueous humor outflow and leading to elevated IOP. According to our findings, when the vault is high, the ACA width decreases and the iris trabecular contact ratio increases, and when they exceed the safety threshold, it may cause the angle to close. There were a few limitations to this study. The first was that the number of patients was relatively small and most of the observation objects are female patients. It is important to continue monitoring the changes of ICL implantation on the anterior segment structures over an extended period of time in a multicenter large patient cohort. In addition, the novel anterior segment parameters could have added more value to this observation. In conclusion, we observed a decrease in anterior chamber parameters 1 month after ICL implantation, and their percentage change correlated with vault. When the vault is greater than 0.659mm, we need to be alert to the angle-closure suspect. Declarations Ethics approval and consent to participate The method of this study was approved by the Ethics Committee of Peking University Third Hospital (M2020240) and adhered to the tenets of the Declaration of Helsinki. In addition, this study was registered and approved on Clinical Trials.gov on 23/06/2020 (registration number: NCT04443231). Each subject was given informed consent after an adequate study explanation. Consent for publication Not applicable. Availability of data and materials The datasets used and analysed during the current study available from the corresponding author on reasonable request. Competing interests The authors declare that they have no competing interests. Funding The study was supported by National Natural Science Foundation of China (82171022, 81974128) and The Capital Health Research and Development of Special (2020-2-4097). Authors contributions Study conception and design: Chuhao Tang, Hong Qi; Data collection: Chuhao Tang, Tong Sun, Lu Zhao; Analysis and interpretation of results: Zhengze Sun, Hongyu Duan, Yilin Liu; Original draft preparation: Chuhao Tang; Review and editing: Wenlong Li, Linbo Bian, Hong Qi. All authors reviewed the results and approved the final version of the manuscript. Acknowledgements We thank all participants for their contribution to the present study. 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Ho SW, Baskaran M, Zheng C, Tun TA, Perera SA, Narayanaswamy AK, Friedman DS, Aung T. Swept source optical coherence tomography measurement of the iris-trabecular contact (ITC) index: a new parameter for angle closure. Graefe's archive for clinical and experimental ophthalmology = Albrecht von Graefes Archiv fur klinische und experimentelle Ophthalmologie. 2013;251(4):1205–11. Zhao T, Zhao M, Xie Q, Fong CW, Chen J, Liu Y, Feng H, Li S, Arnold BF, Aung T, et al. Repeatability and Reproducibility of Anterior Chamber Angle Measurement with Swept-Source Optical Coherence Tomography in Patients with Primary Angle Closure Suspect. Curr Eye Res. 2021;46(12):1853–60. Baskaran M, Ho SW, Tun TA, How AC, Perera SA, Friedman DS, Aung T. Assessment of circumferential angle-closure by the iris-trabecular contact index with swept-source optical coherence tomography. Ophthalmology. 2013;120(11):2226–31. Porporato N, Chong R, Xu BY, Tun TA, Quah JH, Tan M, Baskaran M, Cheng CY, Aung T. Angle closure extent, anterior segment dimensions and intraocular pressure .The British journal of ophthalmology2022. Selvan H, Angmo D, Tomar AS, Yadav S, Sharma A, Dada T. Changes in Intraocular Pressure and Angle Status After Phacoemulsification in Primary Angle Closure Hypertension. J Glaucoma. 2019;28(2):105–10. Gupta B, Angmo D, Yadav S, Dada T, Gupta V, Sihota R. Quantification of Iridotrabecular Contact in Primary Angle-Closure Disease. J Glaucoma. 2020;29(8):681–8. Kim YY, Jung HR. Clarifying the nomenclature for primary angle-closure glaucoma. Surv Ophthalmol. 1997;42(2):125–36. Lowe RF. Clinical types of primary angle closure glaucoma. Aust N Z J Ophthalmol. 1988;16(3):245–50. Additional Declarations No competing interests reported. Cite Share Download PDF Status: Published Journal Publication published 02 May, 2023 Read the published version in BMC Ophthalmology → Version 1 posted Editorial decision: Major revision 27 Feb, 2023 Reviews received at journal 27 Feb, 2023 Reviews received at journal 26 Jan, 2023 Reviewers agreed at journal 20 Jan, 2023 Reviewers invited by journal 20 Jan, 2023 Editor assigned by journal 20 Jan, 2023 Editor invited by journal 11 Jan, 2023 Submission checks completed at journal 11 Jan, 2023 First submitted to journal 01 Jan, 2023 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. 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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-2433622","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":166824899,"identity":"c9990424-1b01-40de-8480-7460239cab03","order_by":0,"name":"Chuhao Tang","email":"","orcid":"","institution":"Peking University Third Hospital","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Chuhao","middleName":"","lastName":"Tang","suffix":""},{"id":166824900,"identity":"0e883efa-e3f5-4bf4-ae82-f41ecd2160c0","order_by":1,"name":"Tong Sun","email":"","orcid":"","institution":"Peking University Third Hospital","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Tong","middleName":"","lastName":"Sun","suffix":""},{"id":166824903,"identity":"11cc5306-3e51-4ab2-93d7-eb4e2a76d825","order_by":2,"name":"Zhengze Sun","email":"","orcid":"","institution":"Peking University Third Hospital","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Zhengze","middleName":"","lastName":"Sun","suffix":""},{"id":166824905,"identity":"8890b2dc-73cd-4ac6-8d77-b5027d9f6e82","order_by":3,"name":"Hongyu Duan","email":"","orcid":"","institution":"Peking University Third Hospital","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Hongyu","middleName":"","lastName":"Duan","suffix":""},{"id":166824908,"identity":"4ea7eb50-70fa-47f8-9044-e9125ebeca84","order_by":4,"name":"Yilin Liu","email":"","orcid":"","institution":"Peking University Third Hospital","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Yilin","middleName":"","lastName":"Liu","suffix":""},{"id":166824911,"identity":"57ccf324-6688-4523-b4ff-b8f85f1062ef","order_by":5,"name":"Lu Zhao","email":"","orcid":"","institution":"Peking University Third Hospital","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Lu","middleName":"","lastName":"Zhao","suffix":""},{"id":166824912,"identity":"97fb4163-6e1d-44b6-9a22-bb87e3ce570d","order_by":6,"name":"Wenlong Li","email":"","orcid":"","institution":"Peking University Third Hospital","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Wenlong","middleName":"","lastName":"Li","suffix":""},{"id":166824913,"identity":"038cb204-7f29-4438-941d-4476f4af5265","order_by":7,"name":"Linbo Bian","email":"","orcid":"","institution":"Peking University Third Hospital","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"Linbo","middleName":"","lastName":"Bian","suffix":""},{"id":166824915,"identity":"78965df5-7583-4b6f-a9b0-bae90a79425b","order_by":8,"name":"Hong Qi","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA0klEQVRIiWNgGAWjYDCCAxCKxwBEfjCwsSNGC2MDTAvjjIK0ZKK1MIC0MPN8OATh4QN8x5ufP/i4x1rGnL338GsbgwPMDOyHj27Ap0XyzDHDxhnP0nkse86lWecY3OFj4ElLu4FPi8GNHMZmngOHeYAMM+Mcg2fMDBI8ZiRosTA4zNhAihbjxwzEaAH5ZeaMA+k8BmfOmDH2GKQlsxHyCzDEHnz4cMDa3uB4j/GHH39s7PjZDx/DqwUKmEEEmwSYJEI5XAvzByJVj4JRMApGwQgDAHpsTwcitQjqAAAAAElFTkSuQmCC","orcid":"","institution":"Peking University Third Hospital","correspondingAuthor":true,"submittingAuthor":false,"prefix":"","firstName":"Hong","middleName":"","lastName":"Qi","suffix":""}],"badges":[],"createdAt":"2023-01-01 15:59:10","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-2433622/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-2433622/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1186/s12886-023-02942-0","type":"published","date":"2023-05-02T20:40:53+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":31540724,"identity":"5cfdb0cf-4a41-4a33-9f5b-b5886ebad7a2","added_by":"auto","created_at":"2023-01-13 15:09:01","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":33446,"visible":true,"origin":"","legend":"\u003cp\u003eAnterior chamber angle parameters measured with SS-OCT. ACW, anterior chamber width; AOD, angle opening distance; ARA, angle recess area; TISA, trabecular iris area; TIA, trabecular-iris angle.\u003c/p\u003e","description":"","filename":"Figure1.png","url":"https://assets-eu.researchsquare.com/files/rs-2433622/v1/bca96f8e1f4d7ddc3aa2e57d.png"},{"id":31542273,"identity":"67df4e0a-ebde-4704-a0ce-ae3f555d9639","added_by":"auto","created_at":"2023-01-13 15:25:01","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":723287,"visible":true,"origin":"","legend":"\u003cp\u003eSS-OCT picture showing the ITC parameter analysis.\u003c/p\u003e","description":"","filename":"Figure2.png","url":"https://assets-eu.researchsquare.com/files/rs-2433622/v1/29544217d51f8d3cc20aeb29.png"},{"id":31540725,"identity":"c45dfb10-2d7f-4357-a630-b0cda4b06341","added_by":"auto","created_at":"2023-01-13 15:09:01","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":25072,"visible":true,"origin":"","legend":"\u003cp\u003eClinical examinations of myopic patients after ICL implantation surgery. (A) Changes in Snellen lines of BCVA at 1 month after ICL implantation. (B) Changes between in UCVA 1 month after ICL implantation and BCVA Preoperatively. (C) Changes in intraocular pressure 1 month after ICL implantation. (D) A scatter plot of the attempted versus the achieved manifest spherical equivalent correction 3 months after ICL implantation. * \u003cem\u003eP\u003c/em\u003e \u0026lt; 0.05 versus preoperative.\u003c/p\u003e","description":"","filename":"Figure3.png","url":"https://assets-eu.researchsquare.com/files/rs-2433622/v1/35e2076ce5ea09973fc28818.png"},{"id":31540728,"identity":"a034621e-360f-4079-ad5c-da69c362cbd7","added_by":"auto","created_at":"2023-01-13 15:09:01","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":153408,"visible":true,"origin":"","legend":"\u003cp\u003eCorrelation analysis of percentage changes of anterior chamber parameters and ITC index and vault after ICL implantation surgery. AOD, angle opening distance; ARA, angle recess area; TISA, trabecular iris area; TIA, trabecular-iris angle. PC, percentage changes; *\u003cem\u003e P\u003c/em\u003e \u0026lt; 0.05; **\u003cem\u003e P\u003c/em\u003e\u0026lt; 0.01.\u003c/p\u003e","description":"","filename":"Figure4.png","url":"https://assets-eu.researchsquare.com/files/rs-2433622/v1/d226a8ab4ac30d008f15e9b6.png"},{"id":31541636,"identity":"55957e60-a197-4a70-9803-51f6df9745b3","added_by":"auto","created_at":"2023-01-13 15:17:01","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":22132,"visible":true,"origin":"","legend":"\u003cp\u003eReceiver operating characteristic curve analyses for the vault identifying eyes with angle-closure suspect.\u003c/p\u003e","description":"","filename":"Figure5.png","url":"https://assets-eu.researchsquare.com/files/rs-2433622/v1/58c85a95c9dc3981689e59df.png"},{"id":44727855,"identity":"f61f8b37-8a0b-469a-a554-7b31b517abcd","added_by":"auto","created_at":"2023-10-16 20:56:16","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":992526,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-2433622/v1/855a1077-09e7-4b43-86bb-81a53bdc76df.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Evaluation of biometric indicators of anterior segment parameters after ICL implantation by swept-source optical coherence tomography","fulltext":[{"header":"Introduction","content":"\u003cp\u003eUncorrected refractive error is the third leading cause of blindness and the first cause of moderate to severe visual impairment worldwide[\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. Myopia is the most common type of refractive error, and uncorrected myopia costs hundreds of billions of dollars in lost productivity worldwide each year[\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]. The global prevalence of myopia has reached 1.406\u0026nbsp;billion people (22.9% of the global population), while about 80%-90% of 18-year-olds in East Asia are myopic and 10%-20% have high myopia. It is estimated that by 2050, 4.758\u0026nbsp;billion people will have myopia (49.8% of the global population) and 938\u0026nbsp;million people will have high myopia (9.8% of the global population)[\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e, \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eAs a kind of intraocular refractive surgery, implantable collamer lens (ICL; Staar Surgical, Nidau, Switzerland) implantation has been widely affirmed for its safety and effectiveness in correcting moderate and high myopia[\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e, \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]. However, the intraocular lens is implanted into the posterior ciliary sulcus in the ICL implantation operation, which has a particular impact on the anatomical structure of the anterior segment and may affect the drainage of aqueous humor due to the reduction or closure of the anterior chamber angle (ACA), resulting in elevated eye pressure or secondary glaucoma[\u003cspan additionalcitationids=\"CR8\" citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eAnterior segment optical coherence tomography (AS-OCT) is a new, non-invasive, high-resolution, cross-sectional imaging technique with broad application potential for the anterior segment. Swept-source OCT (SS-OCT, CASIA SS-1000; Tomey, Nagoya, Japan) is a type of AS-OCT which performs 128 meridional scans and analysis with high-speed A-scan in 2.4 seconds for 360\u0026deg; ACA[\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e]. Its in-built software can be used to determine the degree of 360\u0026deg; iridotrabecular contact area (ITC area) and calculate the ITC index. The anterior chamber depth (ACD) becomes shallower and the ACA becomes narrower after ICL implantation, which increases the risk of peripheral anterior synechia. SS-OCT parameters, including ITC index, may characterise the extent of angle closure and other biometric parameters that reflect mechanical obstruction of the aqueous outflow pathway. Therefore, this study aims to investigate the correlation between ITC index and anterior chamber parameters, angle parameters, vault, and intraocular pressure after ICL implantation, and whether it can be used as an indicator to evaluate the risk of angle closure glaucoma.\u003c/p\u003e"},{"header":"Materials And Methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003eParticipants\u003c/h2\u003e \u003cp\u003eThis study included a total of 47 eyes from 24 participants with moderate and high myopia. All subjects underwent ICL implantation surgery at the Department of Ophthalmology, Peking University Third Hospital between May 2021 and December 2022. Inclusion criteria: 21 to 45 years old, with a spherical equivalent (SE) of greater than \u0026minus;\u0026thinsp;3.00 diopters (D), ACD\u0026thinsp;\u0026ge;\u0026thinsp;2.8mm, corneal endothelial cell count (cECC)\u0026thinsp;\u0026ge;\u0026thinsp;2000 cells/mm\u003csup\u003e2\u003c/sup\u003e, SE remained unchanged for more than 1 year, unsatisfactory vision with contact lenses or spectacles. All patients included in this study had no history of intraocular surgery and showed no other ocular pathologies (uveitis, glaucoma, cataract, keratoconus, severe dry eye, etc.) or serious systemic diseases (diabetes, uncontrolled hypertension, severe hyperthyroidism, etc.).\u003c/p\u003e \u003cp\u003e The method of this study was approved by the Ethics Committee of Peking University Third Hospital (M2020240). In addition, this study was registered and approved on Clinical Trials.gov on 23/06/2020 (registration number: NCT04443231). Each subject was given informed consent after an adequate study explanation.\u003c/p\u003e \u003cp\u003eBefore surgery, each subject got a full ocular examination: the horizontal white-to-white (WTW) distance and axial length (AL) were measured by optical biometry (IOL Master 700; Carl Zeiss Meditec, Jena, Germany), cECC was obtained from each eye, using corneal endothelial microscope (SP-2000; Topcon, Tokyo, Japan). Additionally, each eye was subjected to slit-lamp biomicroscopic examination, corneal topography and funduscopic examination.\u003c/p\u003e \u003cp\u003eMoreover, each patient's eye was assessed for uncorrected visual acuity (UCVA), best corrected visual acuity (BCVA), intraocular pressure (IOP), and manifest refraction before surgery as well as one month afterward. For statistical analysis, the decimal Snellen evaluation of UCVA and BCVA was converted to the logarithm of the minimum angle of resolution (logMAR). With the aid of a non-contact tonometer (CT-80; Topcon, Tokyo, Japan), the IOP was measured. The central vault of the ICL (distance from the posterior surface of ICL to the crystalline lens) was measured using AS-OCT one month after surgery.\u003c/p\u003e \u003cp\u003eThe size of the ICL was calculated with a STAAR sizing formula, based on the result of WTW and ACD. Myopic patients are planned for standard ICL implantation surgeries by the same surgeon (HQ) under similar settings. Preoperatively, in all patients, topical anesthesia (4% lidocaine) was administered 30 minutes before the operation. Through a 3.0-mm temporal corneal incision, the ICL was slowly inserted into the anterior chamber following the implantation of hyaluronic acid (ViscAid, Beijing, China)., under visualization with OPMI Lumera 700 surgical microscope (Carl Zeiss Meditec, Germany), and the Toric ICL implantation surgery was completed with the help of the Callisto Eye System (Carl Zeiss Meditec, Germany). Any remaining viscosurgical device was washed out of the anterior chamber with balanced salt solution. Antibiotic eye drops, steroidal eye drops and artificial tear drops were used postoperatively.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec4\" class=\"Section2\"\u003e \u003ch2\u003eSwept-source optical coherence tomography\u003c/h2\u003e \u003cp\u003eAll subjects underwent SS-OCT imaging before any contact procedure. The subject takes the sitting position, places the chin on the chin rest, and adjusts the position of the eyes until the subject can see the scanning direction of the aiming light. The operator adjusts the area of the eye visible in the iris viewport until the iris is in sharp focus, then uses the controls to make coarse adjustments and moves the jaw rest until the corneoscleral junction is in view. Finally, the scleral spur (SS) was noted in each scan by a single observer with the relevant experience and training who was blinded to the gonioscopic findings.\u003c/p\u003e \u003cp\u003eThe quantitative parameters of SS-OCT are represented as follows (Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e):\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e(1) Anterior Chamber Width (ACW): the distance between the two SS in the OCT scan image.\u003c/p\u003e \u003cp\u003e(2) Angle Opening Distance (AOD): The trabecular mesh at 500 \u0026micro;m away from the SS is drawn as a vertical line perpendicular to the posterior surface of the cornea and intersects with the iris. The distance between the two points is AOD500; the trabecular mesh at 750 \u0026micro;m away from the SS draws a vertical line perpendicular to the posterior surface of the cornea and intersects with the iris. The distance between the two points is AOD750.\u003c/p\u003e \u003cp\u003e(3) Angle Recess Area (ARA): ARA500 is the triangular area bounded by AOD500 (the base) and angle recess (the apex); the triangular area bounded by AOD750 (the base) and angle recess (the apex) is ARA750.\u003c/p\u003e \u003cp\u003e(4) Trabecular Iris Area (TISA): TISA500 refers to the area enclosed by the anterior surface of the iris, AOD500, a line drawn from the SS perpendicular to the plane of the inner scleral wall to the opposing iris and the posterior surface of the cornea; TISA750 refers to the area enclosed by the anterior surface of the iris, AOD750, a line drawn from the SS perpendicular to the plane of the inner scleral wall to the opposing iris and the posterior surface of the cornea.\u003c/p\u003e \u003cp\u003e(5) Trabecular-Iris Angle (TIA): The angle between the two endpoints of AOD500 and the line connecting the angle recess is TIA500, and the angle between the two ends of AOD750 and the line connecting the angle recess is TIA750.\u003c/p\u003e \u003cp\u003e(6) Iridotrabecular Contact Area (ITC Area): Contact area between the iris and angle wall anterior to the SS.\u003c/p\u003e \u003cp\u003e(7) Iridotrabecular Contact Index (ITC index): The inbuilt semiautomated software of the CASIA can be used to measure the ITC index, which is a quantitative measure of the extent of angle closure across 360\u0026deg; of the angles expressed as a percentage (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). The ITC analysis uses the anterior segment cross-sectional meridional images to determine the extent of contact between the iris and angle wall[\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e].\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec5\" class=\"Section2\"\u003e \u003ch2\u003eStatistical Analysis\u003c/h2\u003e \u003cp\u003eSPSS Statistics 26.0 (IBM, Chicago, IL) and R Version 4.2.2 were used to conduct all statistical analyses. The normality of data distributions was assessed using the Shapiro\u0026ndash;Wilk test. All descriptive statistics were summarized and displayed as the mean\u0026thinsp;\u0026plusmn;\u0026thinsp;standard deviation. Continuous variables and normal distribution data were compared using independent sample t tests. In addition, continuous variables that not normally distributed were compared by using the Mann\u0026ndash;Whitney U test. Correlation between different parameters was studied by Pearson or Spearman rank correlation. Receiver operating characteristic (ROC) analysis was used to explore the ability of the vault for identifying eyes with angle-closure suspect. P\u0026thinsp;\u0026lt;\u0026thinsp;0.05 was considered to be statistical significance.\u003c/p\u003e \u003c/div\u003e"},{"header":"Results","content":"\u003cp\u003eDemographics of the enrolled subjects are summarized in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e. Preoperative demographics of the myopic patients underwent ICL implantation in this study. Mean patient age at the time of surgery was 28.33\u0026thinsp;\u0026plusmn;\u0026thinsp;5.58 years (ranges from 21 years to 42 years). The preoperative manifest refraction spherical equivalent (MRSE) was \u0026minus;\u0026thinsp;7.66\u0026thinsp;\u0026plusmn;\u0026thinsp;3.11 (ranges from \u0026minus;\u0026thinsp;3.50 D to -15.00D). The preoperative manifest sphere was \u0026minus;\u0026thinsp;7.24 D\u0026thinsp;\u0026plusmn;\u0026thinsp;3.03 D (ranges from \u0026minus;\u0026thinsp;3.00 D to \u0026minus;\u0026thinsp;14.25 D). The preoperative manifest refractive cylinder was \u0026minus;\u0026thinsp;0.84\u0026thinsp;\u0026plusmn;\u0026thinsp;0.52 D (ranges from 0.00 to \u0026minus;\u0026thinsp;2.50 D). The AL was 26.32\u0026thinsp;\u0026plusmn;\u0026thinsp;1.55 mm (ranges from 24.40 mm to 28.82 mm). WTW was 11.85\u0026thinsp;\u0026plusmn;\u0026thinsp;0.24 mm (ranges from 11.3 mm to 12.3 mm). ACD was 3.23\u0026thinsp;\u0026plusmn;\u0026thinsp;0.22 mm (ranges from 2.89 mm to 3.76mm).\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003ePreoperative demographics of the myopic patients underwent implantable collamer lens implantation in this study\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"2\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCharacteristic\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eMean\u0026thinsp;\u0026plusmn;\u0026thinsp;SD\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNumber, people/eyes\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e24/47\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSex, male/female\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e4/20\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAge (years)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e28.33\u0026thinsp;\u0026plusmn;\u0026thinsp;5.58 (range 21 to 42)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eMRSE (D)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u0026minus;7.66\u0026thinsp;\u0026plusmn;\u0026thinsp;3.11(range \u0026minus;\u0026thinsp;3.50 to -15.00)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eLogMAR BCVA\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.006\u0026thinsp;\u0026plusmn;\u0026thinsp;0.019\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAL (mm)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e26.32\u0026thinsp;\u0026plusmn;\u0026thinsp;1.55\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eWTW (mm)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e11.85\u0026thinsp;\u0026plusmn;\u0026thinsp;0.24\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eACD (mm)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e3.23\u0026thinsp;\u0026plusmn;\u0026thinsp;0.22\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003ecECC (\u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\text{c}\\text{e}\\text{l}\\text{l}\\text{s}/{\\text{mm}}^{\\text{2}}\\)\u003c/span\u003e\u003c/span\u003e)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2903.73\u0026thinsp;\u0026plusmn;\u0026thinsp;272.03\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eICL size (mm)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e12.6\u0026thinsp;\u0026plusmn;\u0026thinsp;0.28\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eICL power (D)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e-8.19\u0026thinsp;\u0026plusmn;\u0026thinsp;3.45 (range \u0026minus;\u0026thinsp;4.00 to -15.50)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"2\"\u003eMRSE, manifest refraction spherical equivalent; LogMAR, logarithm of the minimal angle of resolution; BCVA, best corrected visual acuity; AL, axial length; WTW, white-to-white; ACD, anterior chamber depth; cECC, corneal endothelial cell count\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eAll surgical procedures were uneventful, and no postoperative complications, such as cataract formation, pigment dispersion syndrome, pupillary block, or axis rotation, were seen throughout the observation period. Visual acuity improved for all patients on the first day after surgery. One month postoperatively, only one eye (2.13%) lost one line of vision and 46 eyes (97.87%) maintained or gained BCVA (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003eA). The efficacy index was 1.06\u0026thinsp;\u0026plusmn;\u0026thinsp;0.0.09 (preoperative BCVA: 0.006\u0026thinsp;\u0026plusmn;\u0026thinsp;0.019 logMAR and postoperative UCVA: -0.0015\u0026thinsp;\u0026plusmn;\u0026thinsp;0.0032 logMAR, P\u0026thinsp;\u0026lt;\u0026thinsp;0.05; Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003eB). The mean preoperative IOP and postoperative IOP (15.58\u0026thinsp;\u0026plusmn;\u0026thinsp;2.15 versus 16.44\u0026thinsp;\u0026plusmn;\u0026thinsp;2.77, P\u0026thinsp;\u0026gt;\u0026thinsp;0.05; Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003eC) were not significantly different. At one month postoperatively, 91% and 100% were within \u0026plusmn;\u0026thinsp;0.50 and 1.00 D of the attempted correction, respectively (Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003eD).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eIridotrabecular Contact and Anterior Segment SS-OCT Parameters were assessed at baseline and one month postoperatively (Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). At one month following ICL implantation, the vault is 0.519\u0026thinsp;\u0026plusmn;\u0026thinsp;0.244 mm, the ITC area is 0.396\u0026thinsp;\u0026plusmn;\u0026thinsp;0.37 mm\u003csup\u003e2\u003c/sup\u003e, and the ITC index is 8.143\u0026thinsp;\u0026plusmn;\u0026thinsp;5.439%. All angle parameters, with the exception of ACW, showed a statistically significant reduction on SS-OCT (P\u0026thinsp;\u0026lt;\u0026thinsp;0.05). Mean AOD500, AOD750, ARA500, ARA750, TISA500, TISA750, TIA500 and TIA750 values at one month postoperatively declined by 60.0%, 60.4%, 58.1%, 59.2%, 57.3%, 58.7%, 48.8% and 50.7%, respectively.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eIridotrabecular Contact and Anterior Segment SS-OCT Parameters of ICL patients pre- and postsurgery (Mean\u0026thinsp;\u0026plusmn;\u0026thinsp;SD)\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"3\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003ePresurgery\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003ePostsurgery\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eACW (mm)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eHorizontal\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e11.663\u0026thinsp;\u0026plusmn;\u0026thinsp;0.282\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e11.747\u0026thinsp;\u0026plusmn;\u0026thinsp;0.298\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eVertical\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e12.004\u0026thinsp;\u0026plusmn;\u0026thinsp;0.369\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e11.927\u0026thinsp;\u0026plusmn;\u0026thinsp;0.361\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAverage\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e11.889\u0026thinsp;\u0026plusmn;\u0026thinsp;0.289\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e11.837\u0026thinsp;\u0026plusmn;\u0026thinsp;0.305\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAOD500 (mm)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNasal\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e0.754\u0026thinsp;\u0026plusmn;\u0026thinsp;0.286\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e0.271\u0026thinsp;\u0026plusmn;\u0026thinsp;0.095*\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTemporal\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e0.853\u0026thinsp;\u0026plusmn;\u0026thinsp;0.398\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e0.294\u0026thinsp;\u0026plusmn;\u0026thinsp;0.102*\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSuperior\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e0.675\u0026thinsp;\u0026plusmn;\u0026thinsp;0.343\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e0.25\u0026thinsp;\u0026plusmn;\u0026thinsp;0.091*\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eInferior\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e0.798\u0026thinsp;\u0026plusmn;\u0026thinsp;0.372\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e0.297\u0026thinsp;\u0026plusmn;\u0026thinsp;0.093*\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAverage\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e0.77\u0026thinsp;\u0026plusmn;\u0026thinsp;0.316\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e0.278\u0026thinsp;\u0026plusmn;\u0026thinsp;0.077*\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAOD750 (mm)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNasal\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e0.979\u0026thinsp;\u0026plusmn;\u0026thinsp;0.291\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e0.346\u0026thinsp;\u0026plusmn;\u0026thinsp;0.128*\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTemporal\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e1.087\u0026thinsp;\u0026plusmn;\u0026thinsp;0.409\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e0.385\u0026thinsp;\u0026plusmn;\u0026thinsp;0.133*\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSuperior\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e0.905\u0026thinsp;\u0026plusmn;\u0026thinsp;0.377\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e0.333\u0026thinsp;\u0026plusmn;\u0026thinsp;0.113*\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eInferior\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e1.013\u0026thinsp;\u0026plusmn;\u0026thinsp;0.378\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e0.396\u0026thinsp;\u0026plusmn;\u0026thinsp;0.122*\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAverage\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e0.996\u0026thinsp;\u0026plusmn;\u0026thinsp;0.332\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e0.365\u0026thinsp;\u0026plusmn;\u0026thinsp;0.105*\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eARA500 (mm\u003csup\u003e2\u003c/sup\u003e)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNasal\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e0.273\u0026thinsp;\u0026plusmn;\u0026thinsp;0.13\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e0.105\u0026thinsp;\u0026plusmn;\u0026thinsp;0.041*\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTemporal\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e0.346\u0026thinsp;\u0026plusmn;\u0026thinsp;0.253\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e0.116\u0026thinsp;\u0026plusmn;\u0026thinsp;0.048*\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSuperior\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e0.237\u0026thinsp;\u0026plusmn;\u0026thinsp;0.144\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e0.093\u0026thinsp;\u0026plusmn;\u0026thinsp;0.044*\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eInferior\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e0.325\u0026thinsp;\u0026plusmn;\u0026thinsp;0.201\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e0.114\u0026thinsp;\u0026plusmn;\u0026thinsp;0.04*\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAverage\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e0.295\u0026thinsp;\u0026plusmn;\u0026thinsp;0.152\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e0.107\u0026thinsp;\u0026plusmn;\u0026thinsp;0.031*\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eARA750 (mm\u003csup\u003e2\u003c/sup\u003e)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNasal\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e0.487\u0026thinsp;\u0026plusmn;\u0026thinsp;0.195\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e0.182\u0026thinsp;\u0026plusmn;\u0026thinsp;0.068*\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTemporal\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e0.581\u0026thinsp;\u0026plusmn;\u0026thinsp;0.35\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e0.199\u0026thinsp;\u0026plusmn;\u0026thinsp;0.076*\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSuperior\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e0.434\u0026thinsp;\u0026plusmn;\u0026thinsp;0.226\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e0.163\u0026thinsp;\u0026plusmn;\u0026thinsp;0.072*\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eInferior\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e0.546\u0026thinsp;\u0026plusmn;\u0026thinsp;0.292\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e0.201\u0026thinsp;\u0026plusmn;\u0026thinsp;0.063*\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAverage\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e0.512\u0026thinsp;\u0026plusmn;\u0026thinsp;0.231\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e0.187\u0026thinsp;\u0026plusmn;\u0026thinsp;0.055*\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTISA500 (mm\u003csup\u003e2\u003c/sup\u003e)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNasal\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e0.255\u0026thinsp;\u0026plusmn;\u0026thinsp;0.115\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e0.1\u0026thinsp;\u0026plusmn;\u0026thinsp;0.037*\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTemporal\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e0.306\u0026thinsp;\u0026plusmn;\u0026thinsp;0.187\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e0.111\u0026thinsp;\u0026plusmn;\u0026thinsp;0.042*\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSuperior\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e0.226\u0026thinsp;\u0026plusmn;\u0026thinsp;0.135\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e0.089\u0026thinsp;\u0026plusmn;\u0026thinsp;0.039*\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eInferior\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e0.292\u0026thinsp;\u0026plusmn;\u0026thinsp;0.165\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e0.107\u0026thinsp;\u0026plusmn;\u0026thinsp;0.036*\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAverage\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e0.27\u0026thinsp;\u0026plusmn;\u0026thinsp;0.129\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e0.102\u0026thinsp;\u0026plusmn;\u0026thinsp;0.028*\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTISA750 (mm\u003csup\u003e2\u003c/sup\u003e)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNasal\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e0.47\u0026thinsp;\u0026plusmn;\u0026thinsp;0.183\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e0.177\u0026thinsp;\u0026plusmn;\u0026thinsp;0.065*\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTemporal\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e0.542\u0026thinsp;\u0026plusmn;\u0026thinsp;0.286\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e0.194\u0026thinsp;\u0026plusmn;\u0026thinsp;0.07*\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSuperior\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e0.423\u0026thinsp;\u0026plusmn;\u0026thinsp;0.218\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e0.159\u0026thinsp;\u0026plusmn;\u0026thinsp;0.067*\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eInferior\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e0.513\u0026thinsp;\u0026plusmn;\u0026thinsp;0.258\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e0.195\u0026thinsp;\u0026plusmn;\u0026thinsp;0.059*\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAverage\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e0.487\u0026thinsp;\u0026plusmn;\u0026thinsp;0.208\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e0.181\u0026thinsp;\u0026plusmn;\u0026thinsp;0.052*\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTIA500 (deg.)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNasal\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e60.594\u0026thinsp;\u0026plusmn;\u0026thinsp;15.948\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e29.578\u0026thinsp;\u0026plusmn;\u0026thinsp;12.842*\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTemporal\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e59.531\u0026thinsp;\u0026plusmn;\u0026thinsp;16.145\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e30.356\u0026thinsp;\u0026plusmn;\u0026thinsp;10.016*\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSuperior\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e58.006\u0026thinsp;\u0026plusmn;\u0026thinsp;24.231\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e26.778\u0026thinsp;\u0026plusmn;\u0026thinsp;7.351*\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eInferior\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e58.541\u0026thinsp;\u0026plusmn;\u0026thinsp;20.916\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e28.453\u0026thinsp;\u0026plusmn;\u0026thinsp;7.758*\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAverage\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e59.168\u0026thinsp;\u0026plusmn;\u0026thinsp;16.755\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e28.791\u0026thinsp;\u0026plusmn;\u0026thinsp;6.944*\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTIA750 (deg.)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNasal\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e55.352\u0026thinsp;\u0026plusmn;\u0026thinsp;12.355\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e24.948\u0026thinsp;\u0026plusmn;\u0026thinsp;8.901*\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTemporal\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e55.018\u0026thinsp;\u0026plusmn;\u0026thinsp;12.908\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e27.179\u0026thinsp;\u0026plusmn;\u0026thinsp;8.8*\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSuperior\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e53.733\u0026thinsp;\u0026plusmn;\u0026thinsp;20.866\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e24.573\u0026thinsp;\u0026plusmn;\u0026thinsp;6.277*\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eInferior\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e54.309\u0026thinsp;\u0026plusmn;\u0026thinsp;16.465\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e26.212\u0026thinsp;\u0026plusmn;\u0026thinsp;6.909*\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAverage\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e54.603\u0026thinsp;\u0026plusmn;\u0026thinsp;13.886\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e25.728\u0026thinsp;\u0026plusmn;\u0026thinsp;6.237*\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eITC area (mm\u003csup\u003e2\u003c/sup\u003e)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e0.396\u0026thinsp;\u0026plusmn;\u0026thinsp;0.37\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eITC index (%)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e8.143\u0026thinsp;\u0026plusmn;\u0026thinsp;5.439\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eVault (mm)\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e0.519\u0026thinsp;\u0026plusmn;\u0026thinsp;0.244\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"3\"\u003eACW, anterior chamber width; AOD, angle opening distance; ARA, angle recess area; TISA, trabecular iris area; TIA, trabecular-iris angle; ITC, iridotrabecular contact. * \u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05 versus preoperative.\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eCorrelation analysis examining the relationships between ITC parameters and other factors were conducted next. The ITC index was positively correlated with the vault one month after ICL implantation, but no relationship was found between the ITC index and IOP, angle parameters and the percentage change of angle parameters. However, the vault value after ICL implantation was significantly positively correlated with the percentage change of angle parameters such as AOD500, AOD750, ARA500, ARA750, TISA500, TISA750, TIA500 and TIA750(Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eReceiver operating characteristic curves, with calculations of area under the curve (AUC) and 95% confidence intervals (CIs), were used to assess the performance of the vault for identifying eyes with angle-closure suspect, taking the ITC index\u0026thinsp;\u0026ge;\u0026thinsp;10.76% as the reference standard (Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e). The AUC was 0.73 (95% CI, 0.56\u0026ndash;0.90, \u003cem\u003eP\u003c/em\u003e༜0.05). The vault of \u0026gt;\u0026thinsp;0.659mm was found to be optimal for angle-closure suspect with a sensitivity of 85.2% (95% CI, 67.5\u0026ndash;94.1) and a specificity of 53.9% (95% CI, 29.1\u0026ndash;76.8).\u003c/p\u003e \u003cp\u003e \u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eICL implantation is one of the important means of correcting myopia at present. Compared with corneal refractive surgery, ICL implantation has good safety, stability and reversibility[\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e, \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]. It does not cut the cornea while retaining the accommodation of its lens. The latest generation of ICL V4c drains aqueous humor through the central hole, thus solving the shortcomings of traditional ICL surgery that requires peripheral iridectomy and reduces the damage to ocular structure. Many studies have proved that ICL implantation can effectively improve patients' postoperative visual acuity and visual quality[\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e, \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e]. According to our data, ICL implantation is a safe and effective treatment for myopia. There were no postoperative complications throughout the observation period and the efficacy index was 1.06\u0026thinsp;\u0026plusmn;\u0026thinsp;0.0.09. No eye loses two or more lines of vision after ICL implantation. All eyes were within \u0026plusmn;\u0026thinsp;1.00 D of the attempted correction and 91% of eyes were within \u0026plusmn;\u0026thinsp;0.50 D of the attempted correction. However, when the ICL is implanted in the eye, the loop foot is fixed in the ciliary sulcus of the posterior chamber, which inevitably contacts the posterior surface of the iris. Therefore, the examination of the structure of the chamber angle is very important for the safety after ICL implantation.\u003c/p\u003e \u003cp\u003eIn this work, SS-OCT was primarily used to examine the angle parameters following ICL implantation. At present, the commonly used equipment for observing the chamber angle includes gonioscopy, ultrasound biomicroscope (UBM), Pentacam anterior segment analysis system and OCT[\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e]. Gonioscopy and UBM are contact examinations, which are not suitable for patients in the early postoperative period, and the measurement results depend on the technique and subjective judgment of clinicians. Pentacam uses a Scheimflug camera to scan and shoot, which cannot directly visualize the angle structure since visible light cannot penetrate deep into the tissue. The SS-OCT used in this study is a non-contact rapid anterior segment imaging device with fast imaging speed, high resolution, and good signal-to-noise ratio. It can automatically analyze the image and obtain the position of the scleral protrusion and the angle recess, obtain parameters such as AOD, ARA, TISA, TIA and the proprietary ITC index, and conduct a full-automatic analysis and statistics of the opening and closing of the chamber angle.\u003c/p\u003e \u003cp\u003eThe ACA is an important basis for evaluating the risk factors of glaucoma and the changes of the anterior segment. In 2001, Abela-Formanek et al.[\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e] first used gonioscopy to observe that about 58% of eyes with ACA less than 20 degrees after ICL implantation. Fern\u0026aacute;ndez-Vigo et al.[\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e] reported in 2017 that ACA decreased by 39%-45% in 1 month after ICL V4c implantation using FD-OCT, and remained stable for the next 2 years. Liu et al.[\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e] used SS-OCT to observe that AOD500, TISA500, and TIA500 decreased by 65.4%-71%, 64.1%-69.3%, and 53.8%-61.5% after ICL V4c implantation. Therefore, we evaluate the ACA alteration at 1 month after ICL implantation in myopic patients using SS-OCT. The reductions in ACA parameters observed in our study were similar to those in previous reports. We also found that vault was positively correlated with the percent change in anterior chamber parameters including ACA, but not anterior chamber parameters after ICL implantation. According to Shaffer's classification, if the ACA is greater than 20\u0026deg;, there is no potential for angle closure; if the angle is narrower than 20\u0026deg;, there is a risk of angle closure. Therefore, combined with the changes in ACA before and after ICL surgery, when the ACA before ICL implantation is less than 40\u0026deg; or less than 20\u0026deg; after surgery, or when the vault is high, we should be alert to the risk of ACA closure or glaucoma after surgery.\u003c/p\u003e \u003cp\u003eThe inter- and intra-observer agreement of the ITC index for measuring the degree of angle closure using SS-OCT has been reported to be good[\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e, \u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e]. The index had moderate agreement and good diagnostic performance for angle-closure with gonioscopy as the reference standard with a sensitivity of 71.9% and specificity of 84.3%[\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e]. We found that the ITC index was only positively correlated with the vault after ICL implantation, but not with the postoperative angle parameters or the percentage change of angle parameters. In this study, the highest vault was 1.201 mm and the highest ITC index was 22.2% 1 month after ICL implantation. In all study subjects, no significant increase in IOP or glaucoma was found after surgery, which may be related to the change of anatomical angle earlier than the change of IOP or the degree of angle closure has not decreased below the anatomical threshold[\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e]. Greater ITC could be a biomarker of a higher IOP and greater visual field loss[\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e]. In evaluating the ITC index in the primary angle-closure disease population, Barkha et al.[\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e] found that the ITC index in the primary angle-closure suspect, primary angle closure and primary angle-closure glaucoma groups were 10.76%, 28.53%, and 81.43%, respectively. In this study, therefore, we further employed ROC curves in an effort to identify the performance of the vault for identifying eyes with angle-closure suspect. We found the vault of \u0026gt;\u0026thinsp;0.659mm was optimal for eyes with angle-closure suspect with a sensitivity of 85.2% and a specificity of 53.9%, which was lower than the upper limit of optimal vault recommended by Starr Surgical. Indeed, Asian, female eyes are thought to have a genetic and anatomic predisposition to develop angle closure[\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e, \u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e]. When the intraocular lens was placed in the ciliary sulcus, its posterior \u0026ldquo;pushing\u0026rdquo; mechanism on the iris resulted in secondary angle closure and peripheral iris obstruction, impeding aqueous humor outflow and leading to elevated IOP. According to our findings, when the vault is high, the ACA width decreases and the iris trabecular contact ratio increases, and when they exceed the safety threshold, it may cause the angle to close.\u003c/p\u003e \u003cp\u003eThere were a few limitations to this study. The first was that the number of patients was relatively small and most of the observation objects are female patients. It is important to continue monitoring the changes of ICL implantation on the anterior segment structures over an extended period of time in a multicenter large patient cohort. In addition, the novel anterior segment parameters could have added more value to this observation.\u003c/p\u003e \u003cp\u003eIn conclusion, we observed a decrease in anterior chamber parameters 1 month after ICL implantation, and their percentage change correlated with vault. When the vault is greater than 0.659mm, we need to be alert to the angle-closure suspect.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003eEthics approval and consent to participate\u003c/p\u003e\n\u003cp\u003eThe method of this study was approved by the Ethics Committee of Peking University Third Hospital (M2020240) and adhered to the tenets of the Declaration of Helsinki. In addition, this study was registered and approved on Clinical Trials.gov on 23/06/2020 (registration number: NCT04443231). Each subject was given informed consent after an adequate study explanation.\u003c/p\u003e\n\u003cp\u003eConsent for publication\u003c/p\u003e\n\u003cp\u003eNot applicable.\u003c/p\u003e\n\u003cp\u003eAvailability of data and materials\u003c/p\u003e\n\u003cp\u003eThe datasets used and analysed during the current study available from the corresponding author on reasonable request.\u003c/p\u003e\n\u003cp\u003eCompeting interests\u003c/p\u003e\n\u003cp\u003eThe authors declare that they have no competing interests.\u003c/p\u003e\n\u003cp\u003eFunding\u003c/p\u003e\n\u003cp\u003eThe study was supported by National Natural Science Foundation of China (82171022, 81974128) and The Capital Health Research and Development of Special (2020-2-4097).\u003c/p\u003e\n\u003cp\u003eAuthors contributions\u003c/p\u003e\n\u003cp\u003eStudy conception and design: Chuhao Tang, Hong Qi;\u003c/p\u003e\n\u003cp\u003eData collection: Chuhao Tang, Tong Sun, Lu Zhao;\u003c/p\u003e\n\u003cp\u003eAnalysis and interpretation of results: Zhengze Sun, Hongyu Duan, Yilin Liu;\u003c/p\u003e\n\u003cp\u003eOriginal draft preparation: Chuhao Tang;\u003c/p\u003e\n\u003cp\u003eReview and editing: Wenlong Li, Linbo Bian, Hong Qi.\u003c/p\u003e\n\u003cp\u003eAll authors reviewed the results and approved the final version of the manuscript.\u003c/p\u003e\n\u003cp\u003eAcknowledgements\u003c/p\u003e\n\u003cp\u003eWe thank all participants for their contribution to the present study.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eCauses 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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J Med Association Thailand = Chotmaihet thangphaet. 2017;100(Suppl 1):48\u0026ndash;55.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eRiva I, Micheletti E, Oddone F, Bruttini C, Montescani S, De Angelis G, Rovati L, Weinreb RN, Quaranta L. \u003cb\u003eAnterior Chamber Angle Assessment Techniques: A Review\u003c/b\u003e.Journal of clinical medicine2020, \u003cb\u003e9\u003c/b\u003e(12).\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAbela-Formanek C, Kruger AJ, Dejaco-Ruhswurm I, Pieh S, Skorpik C. Gonioscopic changes after implantation of a posterior chamber lens in phakic myopic eyes. J Cataract Refract Surg. 2001;27(12):1919\u0026ndash;25.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eFern\u0026aacute;ndez-Vigo JI, Macarro-Merino A, Fern\u0026aacute;ndez-Vigo C, Fern\u0026aacute;ndez-Vigo J, De-Pablo-G\u0026oacute;mez-de-Lia\u0026ntilde;o L, Fern\u0026aacute;ndez-P\u0026eacute;rez C, Garc\u0026iacute;a-Feij\u0026oacute;o J. Impacts of Implantable Collamer Lens V4c Placement on Angle Measurements Made by Optical Coherence Tomography: Two-Year Follow-up. Am J Ophthalmol. 2017;181:37\u0026ndash;45.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLiu F, Xia F, Niu L, Zhao J, Wang X, Zhou X. Early Assessment of Circumferential Anterior Segment Structures Following Implantable Collamer Lens V4c Implantation Via SS-OCT. Translational Vis Sci Technol. 2022;11(11):4.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHo SW, Baskaran M, Zheng C, Tun TA, Perera SA, Narayanaswamy AK, Friedman DS, Aung T. Swept source optical coherence tomography measurement of the iris-trabecular contact (ITC) index: a new parameter for angle closure. Graefe's archive for clinical and experimental ophthalmology = Albrecht von Graefes Archiv fur klinische und experimentelle Ophthalmologie. 2013;251(4):1205\u0026ndash;11.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eZhao T, Zhao M, Xie Q, Fong CW, Chen J, Liu Y, Feng H, Li S, Arnold BF, Aung T, et al. Repeatability and Reproducibility of Anterior Chamber Angle Measurement with Swept-Source Optical Coherence Tomography in Patients with Primary Angle Closure Suspect. Curr Eye Res. 2021;46(12):1853\u0026ndash;60.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBaskaran M, Ho SW, Tun TA, How AC, Perera SA, Friedman DS, Aung T. Assessment of circumferential angle-closure by the iris-trabecular contact index with swept-source optical coherence tomography. Ophthalmology. 2013;120(11):2226\u0026ndash;31.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePorporato N, Chong R, Xu BY, Tun TA, Quah JH, Tan M, Baskaran M, Cheng CY, Aung T. \u003cb\u003eAngle closure extent, anterior segment dimensions and intraocular pressure\u003c/b\u003e.The British journal of ophthalmology2022.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSelvan H, Angmo D, Tomar AS, Yadav S, Sharma A, Dada T. Changes in Intraocular Pressure and Angle Status After Phacoemulsification in Primary Angle Closure Hypertension. J Glaucoma. 2019;28(2):105\u0026ndash;10.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGupta B, Angmo D, Yadav S, Dada T, Gupta V, Sihota R. Quantification of Iridotrabecular Contact in Primary Angle-Closure Disease. J Glaucoma. 2020;29(8):681\u0026ndash;8.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKim YY, Jung HR. Clarifying the nomenclature for primary angle-closure glaucoma. Surv Ophthalmol. 1997;42(2):125\u0026ndash;36.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLowe RF. Clinical types of primary angle closure glaucoma. Aust N Z J Ophthalmol. 1988;16(3):245\u0026ndash;50.\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":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"bmc-ophthalmology","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"boph","sideBox":"Learn more about [BMC Ophthalmology](http://bmcophthalmol.biomedcentral.com/)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/boph","title":"BMC Ophthalmology","twitterHandle":"BMC_series","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"em","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"implantable collamer lens implantation surgery, myopia, optical coherence tomography, vault, iridotrabecular contact","lastPublishedDoi":"10.21203/rs.3.rs-2433622/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-2433622/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003ePurpose.\u003c/strong\u003e To evaluate the anterior segment structure alteration after implantable collamer lens (ICL) implantation in myopic patients using swept-source quantitative optical coherence tomography (SS-OCT).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMethods.\u003c/strong\u003e This prospective study included 47 eyes of 24 patients with preoperative spherical equivalent ≥ -3.00 D. Patients underwent ICL implantation at Department of Ophthalmology, Peking University Third Hospital, from May 2021 to December 2022. SS-OCT was used to measure biometry including anterior chamber width (ACW), angle opening distance (AOD), angle recess area (ARA), trabecular iris area (TISA), trabecular-iris angle (TIA), iridotrabecular contact (ITC) area and ITC Index before ICL implantation surgery and at 1 month follow-up.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eResults.\u003c/strong\u003e At one month following ICL implantation, the ITC area is 0.396 ± 0.37 mm\u003csup\u003e2\u003c/sup\u003e, and the ITC index is 8.143 ± 5.439 %. All angle parameters, with the exception of ACW, showed a statistically significant reduction on SS-OCT (P\u0026lt;0.05). Mean AOD500, AOD750, ARA500, ARA750, TISA500, TISA750, TIA500 and TIA750 values at one month postoperatively declined by 60.0%, 60.4%, 58.1%, 59.2%, 57.3%, 58.7%, 48.8% and 50.7%, respectively. Vault was positively correlated with ITC index and the percent change in anterior chamber parameters. The vault of \u0026gt;0.659mm was found to be optimal for angle-closure suspect with a sensitivity of 85.2% and a specificity of 53.9%.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConclusions.\u003c/strong\u003e Anterior chamber parameters decreased 1 month after ICL implantation, and their percentage changes and ITC index correlated with the vault. When the vault is larger than 0.659mm, it is necessary to be alert to possible closed angle suspicion.\u003c/p\u003e","manuscriptTitle":"Evaluation of biometric indicators of anterior segment parameters after ICL implantation by swept-source optical coherence tomography","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2023-01-13 15:08:56","doi":"10.21203/rs.3.rs-2433622/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Major revision","date":"2023-02-28T03:51:29+00:00","index":"","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2023-02-27T13:40:31+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2023-01-27T03:08:47+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"9939e9eb-a031-4fcb-ad97-23b660cec41b","date":"2023-01-20T09:22:48+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2023-01-20T08:28:55+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2023-01-20T06:52:34+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"","date":"2023-01-11T09:58:33+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2023-01-11T09:57:52+00:00","index":"","fulltext":""},{"type":"submitted","content":"BMC Ophthalmology","date":"2023-01-01T15:45:14+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"bmc-ophthalmology","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"boph","sideBox":"Learn more about [BMC Ophthalmology](http://bmcophthalmol.biomedcentral.com/)","snPcode":"","submissionUrl":"https://www.editorialmanager.com/boph","title":"BMC Ophthalmology","twitterHandle":"BMC_series","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"em","reportingPortfolio":"BMC Series","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"ac3f836b-8c33-446c-b327-0933756edb96","owner":[],"postedDate":"January 13th, 2023","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2023-10-16T20:47:31+00:00","versionOfRecord":{"articleIdentity":"rs-2433622","link":"https://doi.org/10.1186/s12886-023-02942-0","journal":{"identity":"bmc-ophthalmology","isVorOnly":false,"title":"BMC Ophthalmology"},"publishedOn":"2023-05-02 20:40:53","publishedOnDateReadable":"May 2nd, 2023"},"versionCreatedAt":"2023-01-13 15:08:56","video":"","vorDoi":"10.1186/s12886-023-02942-0","vorDoiUrl":"https://doi.org/10.1186/s12886-023-02942-0","workflowStages":[]},"version":"v1","identity":"rs-2433622","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-2433622","identity":"rs-2433622","version":["v1"]},"buildId":"7rjqhiLT3MXkJMwkYKINL","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}