Long-term evaluation of anterior segment structures after implantable collamer lens V4c implantation

Long-term evaluation of anterior segment structures after implantable collamer lens V4c implantation | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Long-term evaluation of anterior segment structures after implantable collamer lens V4c implantation Rui Xiong, Zhongjun Tang, Xingtao Zhou, Shengtao Liu This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-8849855/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 6 You are reading this latest preprint version Abstract Purpose To evaluate the long-term outcomes of anterior segment parameters following implantable collamer lens (ICL V4c) implantation in highly myopic patients. Setting A tertiary specialized eye hospital in Shanghai, China. Design Prospective, non-randomized, consecutive case series. Methods This study included 32 eyes of 20 patients with high myopia who underwent ICL V4c implantation with a 3-year follow-up. Preoperative assessments included standard biometry and anterior segment parameters. Postoperative evaluations were conducted at 1 day, 1 month, 3 months, and 3 years. Parameters assessed included corneal endothelium-anterior capsule distance (ACD-L), corneal endothelium-ICL distance (ACD-ICL), ICL-anterior capsule distance (ICL-L), anterior chamber angle (ACA) parameters, and iris metrics. Results ACD-L decreased significantly postoperatively (P < 0.001) but remained stable thereafter. ACD-ICL increased over time, while ICL-L (vault) decreased significantly (P < 0.001), with the most pronounced changes occurring in the first month. All ACA parameters (ACW, AOD500, ARA500, TISA500, TIA500) decreased significantly compared to preoperative values (all P 0.05). Iris parameters (IA, IV) showed transient changes at 1 day post-surgery but returned to baseline levels thereafter. Conclusions ICL V4c implantation demonstrated safety and efficacy during the valuable 3-year follow-up. While the anterior chamber angle narrowed and vault height decreased initially, the anterior segment structure remained stable over the long term. Crucially, the vault decrease was primarily driven by a posterior shift of the ICL rather than an anterior shift of the crystalline lens, confirming the long-term safety regarding cataract formation. high myopia anterior segment structure long-term ICL V4c Figures Figure 1 Figure 2 Figure 3 Introduction ICL V4c is a novel type of posterior chamber phakic intraocular lens. Its central port design enables the natural flow of aqueous humor from the posterior to the anterior chamber, thereby preserving the normal physiological function of the anterior segment and reducing the risk of complications such as pigment dispersion, pupillary block, angle closure, and glaucoma.[ 1 , 2 ] Although prior studies have reported changes in the anterior segment structure following ICL V4c implantation,[ 3 – 5 ] most focus on short-term outcomes(typically 1 year or less). Long-term data extending to 3 years are scarce, particularly for Asian populations. Given that Asian eyes often present with crowded anterior segments and narrower angles, understanding the long-term interaction between the ICL and these structures is critical for assessing the risk of secondary angle-closure glaucoma. Structural changes in the anterior segment, including the endothelium, angle, and iris, are gradual processes, observing these changes over the long term is therefore clinically significant. Furthermore, previous research has indicated that vault height tends to decrease slowly over time,[ 6 , 7 ] but these studies primarily assess vault height alone. Our earlier research demonstrated that ACD-L and ACD-ICL effectively represent the positions of the anterior surface of the lens and the ICL, respectively. Monitoring these parameters over time may provide insights into the mechanism driving vault height changes. However, long-term data for these indicators remain scarce. This study evaluates long-term clinical changes in multiple anterior segment parameters three years after ICL implantation. It also examines shifts in the effective position of the lens and ICL to better understand vault height change trends and associated risks. By offering a comprehensive perspective, this study aims to assist clinicians in selecting ICL surgery and lenses during preoperative and intraoperative planning, ultimately improving correction outcomes and minimizing complications. Patients and Methods Study design: Prospective, non-randomized, consecutive case studies. Patients with high myopia who underwent ICL V4c implantation at our hospital between January 2021 and June 2022 were included. The final follow-up for each patient was conducted at least 3 years postoperatively. Inclusion criteria were: age between 18 years and 45 years; stable refractive error for > 2 years, with an annual progression of < 0.50 D; Spherical refraction between − 6.00-11.50D; preoperative best corrected visual acuity (BCVA) ≥ 0.5; Central anterior chamber depth (CACD) ≥ 2.8 mm; Endothelial cell density (ECD) ≥2000cell/mm2; intraocular pressure (IOP) between 10 to 20 mmHg; open anterior chamber angle. Exclusion criteria were: history of intraocular surgery, corneal abnormalities such as keratoconus, History of uveitis, glaucoma, retinal tears, diabetes, or autoimmune diseases, pregnancy, breastfeeding or other surgical contraindications, spherical power <-18.00 D or cylindrical power <-6.00 D, inability to adhere to postoperative follow-up schedules. This study was approved by the Ethics Committee of Fudan University, Shanghai, and adhered to the principles of the Declaration of Helsinki. All participants were fully informed about the potential and provided written informed consent. Preoperative examination: Uncorrected visual acuity (UCVA), BCVA, IOP, spherical power (Ds), mean corneal horizontal curvature (Km), anterior chamber depth (ACD), horizontal corneal diameter (WTW), axial length (AL), and corrected distance visual acuity (CDVA); anterior segment optical coherence tomography (AS-OCT) was used to obtain all three-dimensional parameters: anterior capsule distance (ACD-L), anterior chamber width (ACW), anterior chamber angle opening distance (AOD(500)), anterior chamber angle recess area (ARA(500)), trabecular meshwork iris area (TISA(500)), trabecular iris angle (TIA(500)), iris thickness (IT(750)), iris area (IA), iris volume (IV), (ACD-ICL), and (ICL-L). Surgical procedure: All surgeries were performed by the same experienced physician specializing in high myopia treatment. Following topical anesthesia, the conjunctival sac was irrigated and a standard disinfectant drape was applied. The ICL V4c was placed in the pusher chamber head, and adjusted to the appropriate position using lens forceps, and the pusher chamber head was mounted on the pusher. After placing an eyelid speculum, a 3.0 mm wide clear corneal tunnel was created at the limbus. The ICL V4c and sodium hyaluronate were injected into the anterior chamber using a push syringe. The four ICL V4c haptics were transferred to the ciliary body using a positioning hook. The ICL V4c was then adjusted to the appropriate position. The astigmatism-type ICL V4c was adjusted according to the axial rotation diagram of the lens astigmatism. The sodium hyaluronate rinsing solution was replaced with a balanced salt solution. At the conclusion of surgery, tobramycin-dexamethasone ointment was applied to the conjunctival sac. Postoperative management included the routine administration of antibiotics, corticosteroids, and non-steroidal anti-inflammatory eye drops to prevent inflammation. Postoperative slit-lamp microscopic examination and intraocular pressure measurements (IOP) were routinely performed 2 h after surgery to observe the patient's ocular condition. Patients with IOP of 21 and 30 mmHg were treated with cartalol eye drops for hypotension. Patients with IOP exceeding 30 mmHg underwent anterior chamber drainage, with close IOP monitoring. Follow-ups were performed at 1mo, 3mo, and 3y after surgery. Observed parameters: Preoperative assessments included the evaluation of general anterior segment features, such as UCVA, BCVA, IOP, Ds, Km, ACD, WTW, AL, and CDVA; Postoperative measurements were conducted at 1 month (1mo), 3 months (3mo), and 3 years (3y) after surgery. These included IOP, ECD, ACD-L, ACW, AOD(500), ARA(500), TISA(500), TIA(500), iris thickness (IT(750)), IA, and IV. Additional post-operative parameters, such as ACD-ICL and ICL-L, were measured at the same follow-up intervals. All measurements were performed by an experienced ophthalmic technician to ensure consistency and reliability. Statistical analysis: Data were analyzed using SPSS 27.0 (IBM Corp., Armonk, NY, USA). The Kolmogorov-Smirnov test was used to assess the normality of data distribution. Anterior segment parameters were in accordance with the normal distribution and were expressed as mean ± standard deviation. The anterior segment parameters at different time points were compared using repeated-measurement data analysis of variance. Further pairwise comparisons were performed using the least significant difference (LSD) t-test, and the Bonferroni test was applied for corrections in pairwise comparisons, and statistical significance was set at P < 0.05. Results General Characteristics Twenty patients (32 eyes) were included (mean age 25.0 ± 3.6 years). Preoperative characteristics are summarized in Supplemental Table 1. All surgeries were successful with no vision-threatening complications. Vault Parameters ACD-L, ACD-ICL, ICL-L Postoperative ACD-L values (1 day to 3 years) were significantly lower than preoperative values (F = 13.42, P < 0.001) but showed no significant difference among postoperative time points. As shown in Fig. 1 , ACD-ICL exhibited a continuous gradual upward trend over the 3-year period (F = 82.149, P < 0.001), stabilizing after 1 month. Conversely, the vault (ICL-L) demonstrated a significant downward trend (F = 107.51, P < 0.001), inversely mirroring the ACD-ICL change, with the most pronounced decrease occurring in the first month (Table 1 ). Table 1 Vault Parameters Parameter Preoperative 1day Postoperative 1Month Postoperative 3Months Postoperative 3Years Postoperative F P ACD-L,mm 3.18 ± 0.24 3.09 ± 0.22 a 3.09 ± 0.24 a 3.11 ± 0.24 a 3.08 ± 0.21 a 13.42 < 0.001 ACD-ICL,mm - 2.11 ± 0.21 2.26 ± 0.16 2.31 ± 0.19 2.4 ± 0.17 82.149 < 0.001 ICL-L,mm - 0.74 ± 0.25 0.58 ± 0.22 0.54 ± 0.2 0.43 ± 0.18 107.51 < 0.001 a Compared with preoperative values, all P 0.05). Pairwise comparisons were all subject to Bonferroni correction. Anterior Chamber Angle Parameters Postoperative ACW, AOD500, ARA500, TISA500, and TIA500 were all significantly lower than preoperative values (all P < 0.001). Figure 2 visually illustrates a characteristic trend where all angle parameters experienced a sharp decline at 1 day post-surgery, followed by a stable plateau phase with no significant differences observed among the follow-up time points up to 3 years (Table 2 ). At 3 years, the reductions were 0.85% (ACW), 121.43% (AOD500), 109.09% (ARA500), 120.0% (TISA500), and 110.31% (TIA500). Table 2 ACA Parameters Parameter Preoperative 1day Postoperative 1Month Postoperative 3Months Postoperative 3Years Postoperative F P ACW,mm 11.91 ± 0.25 11.85 ± 0.29 a 11.8 ± 0.29 a 11.77 ± 0.34 a 11.81 ± 0.25 a 5.92 < 0.001 AOD(500),mm 0.62 ± 0.16 0.28 ± 0.06 a 0.26 ± 0.06 a 0.27 ± 0.07 a 0.28 ± 0.06 a 133.3 < 0.001 ARA(500),mm 2 0.23 ± 0.06 0.11 ± 0.03 a 0.1 ± 0.02 a 0.11 ± 0.03 a 0.11 ± 0.03 a 111.52 < 0.001 TISA(500),mm 2 0.22 ± 0.06 0.1 ± 0.02 a 0.1 ± 0.02 a 0.1 ± 0.03 a 0.1 ± 0.02 a 118.32 < 0.001 TIA(500), ° 48.33 ± 10.22 22.99 ± 4.39 a 23.41 ± 5.55 a 24.98 ± 5.26 a 22.98 ± 4.46 a 154.05 < 0.001 a Compared with preoperative values, all P 0.05). Pairwise comparisons were all subject to Bonferroni correction. Iris Parameters IT750 showed no significant change at any time point (F = 2.91, P = 0.074). However, IA and IV showed significant differences at 1 day post-surgery compared to other time points (P < 0.001). Figure 3 depicts this transient fluctuation, showing a distinct peak in iris area and volume at 1 day post-surgery likely due to surgical manipulation, which rapidly returned to preoperative baseline levels thereafter (Table 3 ). Table 3 Iris Parameters Parameter Preoperative 1day Postoperative 1Month Postoperative 3Months Postoperative 3Years Postoperative F P IT(750),mm 0.42 ± 0.05 0.38 ± 0.14 0.42 ± 0.05 0.43 ± 0.05 0.43 ± 0.05 2.91 0.074 IA,mm 2 1.26 ± 0.15 b 1.35 ± 0.16 1.2 ± 0.17 b 1.17 ± 0.13 b 1.23 ± 0.14 b 16.16 < 0.001 IV,mm 3 35.14 ± 3.67 b 36.41 ± 3.47 33.82 ± 4.1 b 33.36 ± 3.04 b 34.63 ± 3.32 b 15.19 < 0.001 b Compared with 1 day after surgery, all P 0.05). Pairwise comparisons were all subject to Bonferroni correction. Discussion ICL V4c implantation has been widely adopted to enhance vision and improve the quality of life for patients with refractive errors.[ 8 , 9 ] While adverse events associated with the procedure have decreased, anterior segment parameters remain an important indicator for evaluating the safety of surgical procedures.[ 10 , 11 ] Therefore, it is necessary to evaluate long-term changes in anterior segment parameters after ICL implantation. This study represents the first to focus on long-term anterior segment structural changes following ICL implantation in Chinese patients. Our findings demonstrated that IOP and ECD remained comparable to baseline values at the 3-year follow-up. These results align with previous domestic and international studies;[ 6 , 12 , 13 ] indicating that ICL V4c implantation does not significantly impact IOP or corneal endothelial cells, supporting its long-term safety. The anterior chamber angle (ACA) and vault height are pivotal parameters for evaluating intraocular safety and stability after ICL implantation. Long-term changes in anterior chamber angle (ACA) parameters after ICL V4c implantation are particularly important to monitor, especially in Asian populations, such as the Chinese, who are at a higher risk of secondary angle-closure glaucoma due to more crowded anterior segment structures.[ 14 , 15 ] This study showed that all ACA parameters were significantly reduced compared to preoperative values but remained stable throughout the long-term follow-up period, highlighting the importance of maintaining anterior chamber structure and function. In this study, we investigated long-term angle changes after ICL V4c implantation in Chinese patients. Specifically, three years after surgery, the average TIA was 23.59°, and this value remained stable throughout the follow-up period. These results are consistent with the findings of Lin et al.[ 16 ]who observed similar trends during a six-month follow-up. Changes in anterior chamber angle parameters observed in 62 eyes from 62 patients 6 months post ICL V4c implantation 6 months were consistently lower than preoperative values. Notably, the nasal and temporal ACA (n-ACA and t-ACA) remained stable 1mo after surgery, which aligns with our findings at the 3-year follow-up. Previous evaluations of the postoperative ACA relied predominantly on a local quadrant or single-meridian imaging. In contrast, this study utilized 360-degree global swept-source optical coherence tomography (SS-OCT) automatic scanning to obtain comprehensive three-dimensional data. This approach enables a more thorough assessment of ACA changes and offers valuable guidance for patients with narrow preoperative baseline ACA. Specifically, selecting a smaller-diameter ICL V4c implant may mitigate postoperative complications in such cases. Vault height is a critical parameter for assessing the risk of complications, such as cataracts and glaucoma, following ICL implantation. Vault height typically shows a downward trend, which is associated with the posterior shift of the ICL position.[ 17 ] It is important to ensure that the vault height remains within a safe range (≥ 0.15 mm), with the ideal range being 0.25–0.75 mm.[ 18 ] This study found that the vault heights at 1 day, 1 month, 3 months, and 3 years post-surgery were 0.74 ± 0.25 mm, 0.58 ± 0.22 mm, 0.54 ± 0.2 mm, 0.43 ± 0.18 mm, respectively, all within the ideal range. These results suggest that the most significant changes in vault height occur within the first month after surgery, with a relatively gradual downward trend thereafter. Previous studies have also reported a downward trend in vault height both in the short and long term.[ 6 , 7 ] However, they did not explore the specific factors influencing these changes. In contrast, this study used ACD-L and ACD-ICL to track the positional changes of the lens and ICL, respectively, while controlling for pupil diameter. This study showed that during the follow-up period from 1 d to 3 years after surgery, the ACD-ICL increased, while the ACD-L remained unchanged. This suggests that the ICL moved posteriorly within 1 d after surgery, while the lens position remained stable, leading to a decrease in arch height. This differentiation is clinically significant: it indicates that the vault reduction is not caused by the forward movement of the crystalline lens, thereby implying that the risk of mechanically induced cataract does not increase over the long term.We attribute the posterior shift of the ICL to two factors: first, the position of the ICL loop tends to stabilize and may shift posteriorly over time; second, the ICL loop may compress the soft tissue of the ciliary sulcus, which could eventually lead to adaption or even embedding of the ICL. However, this hypothesis requires further imaging confirmation using UBM (ultrasound biomicroscopy). Pigment dispersion due to contact between the iris and the surface of the artificial lens is a known concern following ICL implantation.[ 19 ] In this study, during the 3-year follow-up period, it was observed that iris thickness, iris area, and iris volume all showed significant changes 1 d after surgery, but these parameters gradually returned to preoperative baseline values over the subsequent 3 years, with no significant changes noted in long-term follow-up. The changes observed on the first day after surgery may be attributed to surgical manipulation. These results suggest that the structure of the iris remains unaffected by the ICL, indicating that the procedure is both safe and stable. Furthermore, these findings provide evidence that ICL implantation maintains its safety and stability over the long term. The primary limitation of this study is its relatively small sample size. However, this limitation is partially mitigated by the use of high-resolution 360-degree swept-source AS-OCT, which provided comprehensive volumetric data (IA, IV, TISA, ARA) rather than simple single-meridian measurements, ensuring the reliability of the longitudinal trends observed. While vault height values exhibited a downward trend over time, long-term changes in the position of the ICL haptics could not be assessed due to the absence of UBM, necessitating further research to confirm these findings. Additionally, the evaluation of parameters such as long-term changes in lens density, may not have been comprehensive. Furthermore, a longer follow-up period could provide greater insights into the dynamic changes in the anterior segment. Future studies should address these limitations by incorporating larger sample sizes, more comprehensive evaluations, and extended follow-up periods. In conclusion, this study observed significant anterior segment structural shallowing one day post-surgery, which remained stable over the 3-year follow-up period. The gradual decrease in vault height over time was associated with the posterior shift of the ICL, although the specific mechanisms underlying this trend require further investigation. Despite the absence of postoperative complications, such as elevated IOP or ECD loss, continued long-term follow-up is necessary to monitor anterior segment structural changes in these patients. Declarations Funding: The authors declare that no funds, grants, or other support were received during the preparation of this manuscript. Competing Interests: The authors declare that they have no competing interests and no financial or proprietary interest in the materials presented herein. Author Contributions: Study concept and design were performed by Rui Xiong, Zhongjun Tang, Shengtao Liu, and Xingtao Zhou. Data collection was performed by Rui Xiong and Zhongjun Tang. Analysis and interpretation of data were performed by Rui Xiong and Zhongjun Tang. The first draft of the manuscript was written by Rui Xiong and Zhongjun Tang , and critical revision of the manuscript was performed by Xingtao Zhou and Shengtao Liu. Supervision was provided by Xingtao Zhou and Shengtao Liu. All authors read and approved the final manuscript. Ethics Approval: This study was performed in line with the principles of the Declaration of Helsinki. Approval was granted by the Ethics Committee of Fudan University, Shanghai. Consent to Publish: Not applicable. Data Availability: The datasets generated during and/or analyzed during the current study are available from the corresponding author on reasonable request. Consent to Participate: Written informed consent was obtained from all individual participants included in the study. References Ignacio FVJ, Ana MM, Joaquín FF et al (2016) Computational study of aqueous humor dynamics assessing the vault and the pupil diameter in two posterior-chamber phakic lenses. Invest Ophthalmol Vis Sci 57:4625–4631. Igarashi A (2019) Posterior chamber phakic IOLs vs. LASIK: Benefits and complications. Expert Rev Ophthalmol 14:43–52. Fernández-Vega-Cueto L, Alfonso-Bartolozzi B, Lisa C et al (2021) Seven-year follow-up of posterior chamber phakic intraocular lens with central port design. Eye Vis (Lond) 8:23. Yang W, Zhao J, Sun L et al (2021) Four-year observation of the changes in corneal endothelium cell density and correlated factors after Implantable Collamer Lens V4c implantation. Br J Ophthalmol 105:625–630. Igarashi A, Kamiya K, Ichikawa K et al (2022) Multicenter clinical outcomes of hole implantable collamer lens implantation in middle-aged patients. Sci Rep 12:4236. Boliang L, Xun C, Mingrui C et al (2023) Long-term vault changes in different levels and factors affecting vault change after implantation of implantable collamer lens with a central hole. Ophthalmol Ther 12:499–512. Haiting C, Guangzeng N, Yuxiang F, Jingxue M (2016) Comparison of intraocular pressure and vault after implantation of implantable collamer lens with and without a central hole. BMC Ophthalmol 16:203. Alonso-Juárez E, Velázquez-Villoria D (2022) Low diopter phakic implantable collamer lens: Refractive and visual outcomes in low myopia and myopic astigmatism. Clin Ophthalmol 16:2969–2977. Bhandari V, Karandikar S, Reddy JK, Relekar K (2015) Implantable collamer lens V4b and V4c for correction of high myopia. J Curr Ophthalmol 27:76–81. Chen X, Wang X, Xu Y et al (2021) Five-year outcomes of EVO implantable collamer lens implantation for the correction of high myopia and super high myopia. Eye Vis (Lond) 8:40. Alfonso JF, Fernández-Vega-Cueto L, Alfonso-Bartolozzi B et al (2019) Five-year follow-up of correction of myopia: Posterior chamber phakic intraocular lens with a central port design. J Refract Surg 35:169–176. Li HM, Nie DJ, Zhong B et al (2023) Efficacy of implantable collamer lens V4c implantation in the treatment of high myopia. Int Eye Sci 23:1409–1412. Chen X, Shen Y, Xu H et al (2020) One-year natural course of corneal densitometry in high myopic patients after implantation of an implantable collamer lens (model V4c). BMC Ophthalmol 20:50. Zhao J, Zhao J, Yang W et al (2021) Peripheral anterior chamber depth and angle measurements using Pentacam after implantation of toric and non-toric implantable collamer lenses. Front Med (Lausanne) 8:610590. Moghimi S, Bijani F, Chen R et al (2018) Anterior segment dimensions following laser iridotomy in acute primary angle closure and fellow eyes. Am J Ophthalmol 186:59–68. Lin Q, Yang D, Zhou X (2022) Early outcomes of anterior segment parameters after implantable collamer lens V4c implantation. BMC Ophthalmol 22:429. Yuhao Y, Jing Z, Lingling N et al (2022) Long-term evaluation of anterior lens density after implantable collamer lens V4c implantation in patients with myopia over 40 years old. Br J Ophthalmol 106:1523–1529. Cerpa Manito S, Sánchez Trancón A, Torrado Sierra O et al (2021) Biometric and ICL-related risk factors associated to sub-optimal vaults in eyes implanted with implantable collamer lenses. Eye Vis (Lond) 8:26. Garcia-De la Rosa G, Olivo-Payne A, Serna-Ojeda JC et al (2018) Anterior segment optical coherence tomography angle and vault analysis after toric and non-toric implantable collamer lens V4c implantation in patients with high myopia. Br J Ophthalmol 102:544–548. Additional Declarations No competing interests reported. Supplementary Files SupplementalTable1.docx Cite Share Download PDF Status: Under Review Version 1 posted Reviews received at journal 14 Apr, 2026 Reviewers agreed at journal 14 Apr, 2026 Reviewers invited by journal 13 Apr, 2026 Editor assigned by journal 14 Feb, 2026 Submission checks completed at journal 14 Feb, 2026 First submitted to journal 11 Feb, 2026 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-8849855","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":624280889,"identity":"d634836a-0fe2-40a1-a261-c131e80a706f","order_by":0,"name":"Rui Xiong","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAABBUlEQVRIie2QsUrEQBCGNwxsms2lnSWH+ggrgSB44IPYrARyjfZXHBpYuCut7zlsLCwWBtbm4F4hNtaxEFJYmOUaQZK7UnC/YgaG/2OYYSwQ+IvAvgkO0bq7+UJIAag5SpnExuJHfRHLNa/UUdtOhNNyUy9StRNnOJZUr+DePl9oyvFW5ckzZjkJpthydj2kSMPn+fSdhFfKZIt5QYltmKvu6gElBVFkaPeKr2VBE62imgYV/kM5N319eDJC4Zjit8jWK8KV0WaFoOCA0t9SZczOBY+NY+0WAal/sh65Re3Iyc5eXp2aaMX04h7SR6KmXc4GFQ+IXyM9EvdE3YFAIBAI/HO+AbWMUGKdDtdWAAAAAElFTkSuQmCC","orcid":"","institution":"The Affiliated Eye Hospital, Jiangxi Medical College, Nanchang University","correspondingAuthor":true,"prefix":"","firstName":"Rui","middleName":"","lastName":"Xiong","suffix":""},{"id":624280890,"identity":"15f1f16e-18b7-481d-8e05-126a861b363c","order_by":1,"name":"Zhongjun Tang","email":"","orcid":"","institution":"Department of Ophthalmology, Eye and Ear, Nose, and Throat Hospital of Fudan University","correspondingAuthor":false,"prefix":"","firstName":"Zhongjun","middleName":"","lastName":"Tang","suffix":""},{"id":624280891,"identity":"298e28fc-aeb9-4bc8-8748-877a96e20d0e","order_by":2,"name":"Xingtao Zhou","email":"","orcid":"","institution":"Department of Ophthalmology, Eye and Ear, Nose, and Throat Hospital of Fudan University","correspondingAuthor":false,"prefix":"","firstName":"Xingtao","middleName":"","lastName":"Zhou","suffix":""},{"id":624280892,"identity":"5d0a4307-141e-4e45-b0ae-6a91b7edfe11","order_by":3,"name":"Shengtao Liu","email":"","orcid":"","institution":"Department of Ophthalmology, Eye and Ear, Nose, and Throat Hospital of Fudan University","correspondingAuthor":false,"prefix":"","firstName":"Shengtao","middleName":"","lastName":"Liu","suffix":""}],"badges":[],"createdAt":"2026-02-11 09:38:50","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-8849855/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-8849855/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":107486199,"identity":"cf5042c4-0aa6-47ac-9d9b-5f02071765ed","added_by":"auto","created_at":"2026-04-22 02:37:45","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":113469,"visible":true,"origin":"","legend":"\u003cp\u003eLongitudinal changes in vault parameters over the 3-year follow-up period. The graphs demonstrate the trends for Corneal Endothelium-Anterior Capsule Distance (ACD-L), Corneal Endothelium-ICL Distance (ACD-ICL), and ICL-Anterior Capsule Distance (ICL-L/Vault). Error bars represent standard deviation.\u003c/p\u003e","description":"","filename":"floatimage1.png","url":"https://assets-eu.researchsquare.com/files/rs-8849855/v1/27842b735413db484cb3afc7.png"},{"id":107486096,"identity":"242688a9-6915-4447-bce6-89a7e8b1202d","added_by":"auto","created_at":"2026-04-22 02:37:25","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":191625,"visible":true,"origin":"","legend":"\u003cp\u003eLongitudinal changes in Anterior Chamber Angle (ACA) parameters. The plots show the preoperative versus postoperative trends for ACW, AOD500, ARA500, TISA500, and TIA500, indicating a sharp decrease post-surgery followed by long-term stability.\u003c/p\u003e","description":"","filename":"floatimage2.png","url":"https://assets-eu.researchsquare.com/files/rs-8849855/v1/ae26bd223ecdce7f8f1fef1e.png"},{"id":107486110,"identity":"d4f5c7c2-d2e1-4fa2-86e0-e25529d62812","added_by":"auto","created_at":"2026-04-22 02:37:26","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":241612,"visible":true,"origin":"","legend":"\u003cp\u003eLongitudinal changes in Iris parameters. The graphs illustrate the trends for Iris Thickness (IT750), Iris Area (IA), and Iris Volume (IV), highlighting transient changes at 1 day post-surgery. (Note: IV is represented in mm³).\u003c/p\u003e","description":"","filename":"floatimage3.png","url":"https://assets-eu.researchsquare.com/files/rs-8849855/v1/d51671927642c994abbc7d89.png"},{"id":107488050,"identity":"623d1cb6-12b7-41df-8918-62cab09b5123","added_by":"auto","created_at":"2026-04-22 02:43:22","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":941095,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-8849855/v1/2c7a20df-803b-4944-a906-7f09cfb79e56.pdf"},{"id":107486108,"identity":"9d5e7559-b1d4-4340-8b1e-1d7c07e8154c","added_by":"auto","created_at":"2026-04-22 02:37:26","extension":"docx","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":13204,"visible":true,"origin":"","legend":"","description":"","filename":"SupplementalTable1.docx","url":"https://assets-eu.researchsquare.com/files/rs-8849855/v1/44959841e2a56f02e9768e69.docx"}],"financialInterests":"No competing interests reported.","formattedTitle":"Long-term evaluation of anterior segment structures after implantable collamer lens V4c implantation","fulltext":[{"header":"Introduction","content":"\u003cp\u003eICL V4c is a novel type of posterior chamber phakic intraocular lens. Its central port design enables the natural flow of aqueous humor from the posterior to the anterior chamber, thereby preserving the normal physiological function of the anterior segment and reducing the risk of complications such as pigment dispersion, pupillary block, angle closure, and glaucoma.[\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e] Although prior studies have reported changes in the anterior segment structure following ICL V4c implantation,[\u003cspan additionalcitationids=\"CR4\" citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e] most focus on short-term outcomes(typically 1 year or less). Long-term data extending to 3 years are scarce, particularly for Asian populations. Given that Asian eyes often present with crowded anterior segments and narrower angles, understanding the long-term interaction between the ICL and these structures is critical for assessing the risk of secondary angle-closure glaucoma. Structural changes in the anterior segment, including the endothelium, angle, and iris, are gradual processes, observing these changes over the long term is therefore clinically significant. Furthermore, previous research has indicated that vault height tends to decrease slowly over time,[\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e, \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e] but these studies primarily assess vault height alone. Our earlier research demonstrated that ACD-L and ACD-ICL effectively represent the positions of the anterior surface of the lens and the ICL, respectively. Monitoring these parameters over time may provide insights into the mechanism driving vault height changes. However, long-term data for these indicators remain scarce.\u003c/p\u003e \u003cp\u003eThis study evaluates long-term clinical changes in multiple anterior segment parameters three years after ICL implantation. It also examines shifts in the effective position of the lens and ICL to better understand vault height change trends and associated risks. By offering a comprehensive perspective, this study aims to assist clinicians in selecting ICL surgery and lenses during preoperative and intraoperative planning, ultimately improving correction outcomes and minimizing complications.\u003c/p\u003e"},{"header":"Patients and Methods","content":"\u003cp\u003eStudy design: Prospective, non-randomized, consecutive case studies. Patients with high myopia who underwent ICL V4c implantation at our hospital between January 2021 and June 2022 were included. The final follow-up for each patient was conducted at least 3 years postoperatively. Inclusion criteria were: age between 18 years and 45 years; stable refractive error for \u0026gt;\u0026thinsp;2 years, with an annual progression of \u0026lt;\u0026thinsp;0.50 D; Spherical refraction between \u0026minus;\u0026thinsp;6.00-11.50D; preoperative best corrected visual acuity (BCVA)\u0026thinsp;\u0026ge;\u0026thinsp;0.5; Central anterior chamber depth (CACD)\u0026thinsp;\u0026ge;\u0026thinsp;2.8 mm; Endothelial cell density (ECD) \u0026ge;2000cell/mm2; intraocular pressure (IOP) between 10 to 20 mmHg; open anterior chamber angle. Exclusion criteria were: history of intraocular surgery, corneal abnormalities such as keratoconus, History of uveitis, glaucoma, retinal tears, diabetes, or autoimmune diseases, pregnancy, breastfeeding or other surgical contraindications, spherical power \u0026lt;-18.00 D or cylindrical power \u0026lt;-6.00 D, inability to adhere to postoperative follow-up schedules. This study was approved by the Ethics Committee of Fudan University, Shanghai, and adhered to the principles of the Declaration of Helsinki. All participants were fully informed about the potential and provided written informed consent.\u003c/p\u003e \u003cp\u003ePreoperative examination: Uncorrected visual acuity (UCVA), BCVA, IOP, spherical power (Ds), mean corneal horizontal curvature (Km), anterior chamber depth (ACD), horizontal corneal diameter (WTW), axial length (AL), and corrected distance visual acuity (CDVA); anterior segment optical coherence tomography (AS-OCT) was used to obtain all three-dimensional parameters: anterior capsule distance (ACD-L), anterior chamber width (ACW), anterior chamber angle opening distance (AOD(500)), anterior chamber angle recess area (ARA(500)), trabecular meshwork iris area (TISA(500)), trabecular iris angle (TIA(500)), iris thickness (IT(750)), iris area (IA), iris volume (IV), (ACD-ICL), and (ICL-L).\u003c/p\u003e \u003cp\u003eSurgical procedure: All surgeries were performed by the same experienced physician specializing in high myopia treatment. Following topical anesthesia, the conjunctival sac was irrigated and a standard disinfectant drape was applied. The ICL V4c was placed in the pusher chamber head, and adjusted to the appropriate position using lens forceps, and the pusher chamber head was mounted on the pusher. After placing an eyelid speculum, a 3.0 mm wide clear corneal tunnel was created at the limbus. The ICL V4c and sodium hyaluronate were injected into the anterior chamber using a push syringe. The four ICL V4c haptics were transferred to the ciliary body using a positioning hook. The ICL V4c was then adjusted to the appropriate position. The astigmatism-type ICL V4c was adjusted according to the axial rotation diagram of the lens astigmatism. The sodium hyaluronate rinsing solution was replaced with a balanced salt solution. At the conclusion of surgery, tobramycin-dexamethasone ointment was applied to the conjunctival sac. Postoperative management included the routine administration of antibiotics, corticosteroids, and non-steroidal anti-inflammatory eye drops to prevent inflammation.\u003c/p\u003e \u003cp\u003ePostoperative slit-lamp microscopic examination and intraocular pressure measurements (IOP) were routinely performed 2 h after surgery to observe the patient's ocular condition. Patients with IOP of 21 and 30 mmHg were treated with cartalol eye drops for hypotension. Patients with IOP exceeding 30 mmHg underwent anterior chamber drainage, with close IOP monitoring. Follow-ups were performed at 1mo, 3mo, and 3y after surgery.\u003c/p\u003e \u003cp\u003eObserved parameters: Preoperative assessments included the evaluation of general anterior segment features, such as UCVA, BCVA, IOP, Ds, Km, ACD, WTW, AL, and CDVA; Postoperative measurements were conducted at 1 month (1mo), 3 months (3mo), and 3 years (3y) after surgery. These included IOP, ECD, ACD-L, ACW, AOD(500), ARA(500), TISA(500), TIA(500), iris thickness (IT(750)), IA, and IV. Additional post-operative parameters, such as ACD-ICL and ICL-L, were measured at the same follow-up intervals. All measurements were performed by an experienced ophthalmic technician to ensure consistency and reliability.\u003c/p\u003e \u003cp\u003eStatistical analysis: Data were analyzed using SPSS 27.0 (IBM Corp., Armonk, NY, USA). The Kolmogorov-Smirnov test was used to assess the normality of data distribution. Anterior segment parameters were in accordance with the normal distribution and were expressed as mean\u0026thinsp;\u0026plusmn;\u0026thinsp;standard deviation. The anterior segment parameters at different time points were compared using repeated-measurement data analysis of variance. Further pairwise comparisons were performed using the least significant difference (LSD) t-test, and the Bonferroni test was applied for corrections in pairwise comparisons, and statistical significance was set at P\u0026thinsp;\u0026lt;\u0026thinsp;0.05.\u003c/p\u003e"},{"header":"Results","content":"\u003cp\u003eGeneral Characteristics Twenty patients (32 eyes) were included (mean age 25.0\u0026thinsp;\u0026plusmn;\u0026thinsp;3.6 years). Preoperative characteristics are summarized in Supplemental Table\u0026nbsp;1. All surgeries were successful with no vision-threatening complications.\u003c/p\u003e \u003cp\u003e \u003cstrong\u003eVault Parameters\u003c/strong\u003e \u003cp\u003eACD-L, ACD-ICL, ICL-L Postoperative ACD-L values (1 day to 3 years) were significantly lower than preoperative values (F\u0026thinsp;=\u0026thinsp;13.42, P\u0026thinsp;\u0026lt;\u0026thinsp;0.001) but showed no significant difference among postoperative time points. As shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e, ACD-ICL exhibited a continuous gradual upward trend over the 3-year period (F\u0026thinsp;=\u0026thinsp;82.149, P\u0026thinsp;\u0026lt;\u0026thinsp;0.001), stabilizing after 1 month. Conversely, the vault (ICL-L) demonstrated a significant downward trend (F\u0026thinsp;=\u0026thinsp;107.51, P\u0026thinsp;\u0026lt;\u0026thinsp;0.001), inversely mirroring the ACD-ICL change, with the most pronounced decrease occurring in the first month (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e).\u003c/p\u003e \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\u003eVault Parameters\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"8\"\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 \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eParameter\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003ePreoperative\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1day\u003c/p\u003e \u003cp\u003ePostoperative\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1Month\u003c/p\u003e \u003cp\u003ePostoperative\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003e3Months\u003c/p\u003e \u003cp\u003ePostoperative\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003e3Years\u003c/p\u003e \u003cp\u003ePostoperative\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c7\"\u003e \u003cp\u003eF\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c8\"\u003e \u003cp\u003eP\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eACD-L,mm\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e3.18\u0026thinsp;\u0026plusmn;\u0026thinsp;0.24\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e3.09\u0026thinsp;\u0026plusmn;\u0026thinsp;0.22\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e3.09\u0026thinsp;\u0026plusmn;\u0026thinsp;0.24\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e3.11\u0026thinsp;\u0026plusmn;\u0026thinsp;0.24\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e3.08\u0026thinsp;\u0026plusmn;\u0026thinsp;0.21\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e13.42\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eACD-ICL,mm\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e2.11\u0026thinsp;\u0026plusmn;\u0026thinsp;0.21\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e2.26\u0026thinsp;\u0026plusmn;\u0026thinsp;0.16\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e2.31\u0026thinsp;\u0026plusmn;\u0026thinsp;0.19\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e2.4\u0026thinsp;\u0026plusmn;\u0026thinsp;0.17\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e82.149\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eICL-L,mm\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e-\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.74\u0026thinsp;\u0026plusmn;\u0026thinsp;0.25\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.58\u0026thinsp;\u0026plusmn;\u0026thinsp;0.22\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.54\u0026thinsp;\u0026plusmn;\u0026thinsp;0.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.43\u0026thinsp;\u0026plusmn;\u0026thinsp;0.18\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e107.51\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003csup\u003ea\u003c/sup\u003eCompared with preoperative values, all P\u0026thinsp;\u0026lt;\u0026thinsp;0.05, and there was no significant difference between different postoperative time points (P\u0026thinsp;\u0026gt;\u0026thinsp;0.05). Pairwise comparisons were all subject to Bonferroni correction.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003cb\u003eAnterior Chamber Angle Parameters\u003c/b\u003e Postoperative ACW, AOD500, ARA500, TISA500, and TIA500 were all significantly lower than preoperative values (all P\u0026thinsp;\u0026lt;\u0026thinsp;0.001). Figure\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e visually illustrates a characteristic trend where all angle parameters experienced a sharp decline at 1 day post-surgery, followed by a stable plateau phase with no significant differences observed among the follow-up time points up to 3 years (Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e). At 3 years, the reductions were 0.85% (ACW), 121.43% (AOD500), 109.09% (ARA500), 120.0% (TISA500), and 110.31% (TIA500).\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\u003eACA Parameters\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"8\"\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=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eParameter\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003ePreoperative\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1day\u003c/p\u003e \u003cp\u003ePostoperative\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1Month\u003c/p\u003e \u003cp\u003ePostoperative\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003e3Months\u003c/p\u003e \u003cp\u003ePostoperative\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003e3Years\u003c/p\u003e \u003cp\u003ePostoperative\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c7\"\u003e \u003cp\u003eF\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c8\"\u003e \u003cp\u003eP\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=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e11.91\u0026thinsp;\u0026plusmn;\u0026thinsp;0.25\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e11.85\u0026thinsp;\u0026plusmn;\u0026thinsp;0.29\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e11.8\u0026thinsp;\u0026plusmn;\u0026thinsp;0.29\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e11.77\u0026thinsp;\u0026plusmn;\u0026thinsp;0.34\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e11.81\u0026thinsp;\u0026plusmn;\u0026thinsp;0.25\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e5.92\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eAOD(500),mm\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e0.62\u0026thinsp;\u0026plusmn;\u0026thinsp;0.16\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.28\u0026thinsp;\u0026plusmn;\u0026thinsp;0.06\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.26\u0026thinsp;\u0026plusmn;\u0026thinsp;0.06\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.27\u0026thinsp;\u0026plusmn;\u0026thinsp;0.07\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.28\u0026thinsp;\u0026plusmn;\u0026thinsp;0.06\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e133.3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eARA(500),mm\u003csup\u003e2\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e0.23\u0026thinsp;\u0026plusmn;\u0026thinsp;0.06\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.11\u0026thinsp;\u0026plusmn;\u0026thinsp;0.03\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.1\u0026thinsp;\u0026plusmn;\u0026thinsp;0.02\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.11\u0026thinsp;\u0026plusmn;\u0026thinsp;0.03\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.11\u0026thinsp;\u0026plusmn;\u0026thinsp;0.03\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e111.52\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTISA(500),mm\u003csup\u003e2\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e0.22\u0026thinsp;\u0026plusmn;\u0026thinsp;0.06\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e0.1\u0026thinsp;\u0026plusmn;\u0026thinsp;0.02\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.1\u0026thinsp;\u0026plusmn;\u0026thinsp;0.02\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.1\u0026thinsp;\u0026plusmn;\u0026thinsp;0.03\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.1\u0026thinsp;\u0026plusmn;\u0026thinsp;0.02\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e118.32\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eTIA(500),\u003csup\u003e\u0026deg;\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c2\"\u003e \u003cp\u003e48.33\u0026thinsp;\u0026plusmn;\u0026thinsp;10.22\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e22.99\u0026thinsp;\u0026plusmn;\u0026thinsp;4.39\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e23.41\u0026thinsp;\u0026plusmn;\u0026thinsp;5.55\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e24.98\u0026thinsp;\u0026plusmn;\u0026thinsp;5.26\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e22.98\u0026thinsp;\u0026plusmn;\u0026thinsp;4.46\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e154.05\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003csup\u003ea\u003c/sup\u003e Compared with preoperative values, all P\u0026thinsp;\u0026lt;\u0026thinsp;0.05, and there was no significant difference between different postoperative time points (P\u0026thinsp;\u0026gt;\u0026thinsp;0.05). Pairwise comparisons were all subject to Bonferroni correction.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003e \u003cb\u003eIris Parameters\u003c/b\u003e IT750 showed no significant change at any time point (F\u0026thinsp;=\u0026thinsp;2.91, P\u0026thinsp;=\u0026thinsp;0.074). However, IA and IV showed significant differences at 1 day post-surgery compared to other time points (P\u0026thinsp;\u0026lt;\u0026thinsp;0.001). Figure\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e depicts this transient fluctuation, showing a distinct peak in iris area and volume at 1 day post-surgery likely due to surgical manipulation, which rapidly returned to preoperative baseline levels thereafter (Table\u0026nbsp;\u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e).\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab3\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eIris Parameters\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"8\"\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 \u003cdiv align=\"char\" char=\"\u0026plusmn;\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e \u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eParameter\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003ePreoperative\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003e1day\u003c/p\u003e \u003cp\u003ePostoperative\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1Month\u003c/p\u003e \u003cp\u003ePostoperative\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003e3Months\u003c/p\u003e \u003cp\u003ePostoperative\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003e3Years\u003c/p\u003e \u003cp\u003ePostoperative\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c7\"\u003e \u003cp\u003eF\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c8\"\u003e \u003cp\u003eP\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eIT(750),mm\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e0.42\u0026thinsp;\u0026plusmn;\u0026thinsp;0.05\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e0.38\u0026thinsp;\u0026plusmn;\u0026thinsp;0.14\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e0.42\u0026thinsp;\u0026plusmn;\u0026thinsp;0.05\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e0.43\u0026thinsp;\u0026plusmn;\u0026thinsp;0.05\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e0.43\u0026thinsp;\u0026plusmn;\u0026thinsp;0.05\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e2.91\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e0.074\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eIA,mm\u003csup\u003e2\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1.26\u0026thinsp;\u0026plusmn;\u0026thinsp;0.15\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e1.35\u0026thinsp;\u0026plusmn;\u0026thinsp;0.16\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1.2\u0026thinsp;\u0026plusmn;\u0026thinsp;0.17\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1.17\u0026thinsp;\u0026plusmn;\u0026thinsp;0.13\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e1.23\u0026thinsp;\u0026plusmn;\u0026thinsp;0.14\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e16.16\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eIV,mm\u003csup\u003e3\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e35.14\u0026thinsp;\u0026plusmn;\u0026thinsp;3.67\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\"\u0026plusmn;\" colname=\"c3\"\u003e \u003cp\u003e36.41\u0026thinsp;\u0026plusmn;\u0026thinsp;3.47\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e33.82\u0026thinsp;\u0026plusmn;\u0026thinsp;4.1\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e33.36\u0026thinsp;\u0026plusmn;\u0026thinsp;3.04\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e34.63\u0026thinsp;\u0026plusmn;\u0026thinsp;3.32\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e15.19\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e\u0026lt;\u0026thinsp;0.001\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003csup\u003eb\u003c/sup\u003eCompared with 1 day after surgery, all P\u0026thinsp;\u0026lt;\u0026thinsp;0.05, but there was no significant difference between preoperative and other postoperative time points (P\u0026thinsp;\u0026gt;\u0026thinsp;0.05). Pairwise comparisons were all subject to Bonferroni correction.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eICL V4c implantation has been widely adopted to enhance vision and improve the quality of life for patients with refractive errors.[\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e, \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e] While adverse events associated with the procedure have decreased, anterior segment parameters remain an important indicator for evaluating the safety of surgical procedures.[\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e, \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e] Therefore, it is necessary to evaluate long-term changes in anterior segment parameters after ICL implantation. This study represents the first to focus on long-term anterior segment structural changes following ICL implantation in Chinese patients.\u003c/p\u003e \u003cp\u003eOur findings demonstrated that IOP and ECD remained comparable to baseline values at the 3-year follow-up. These results align with previous domestic and international studies;[\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e, \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e, \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e] indicating that ICL V4c implantation does not significantly impact IOP or corneal endothelial cells, supporting its long-term safety.\u003c/p\u003e \u003cp\u003eThe anterior chamber angle (ACA) and vault height are pivotal parameters for evaluating intraocular safety and stability after ICL implantation. Long-term changes in anterior chamber angle (ACA) parameters after ICL V4c implantation are particularly important to monitor, especially in Asian populations, such as the Chinese, who are at a higher risk of secondary angle-closure glaucoma due to more crowded anterior segment structures.[\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e, \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e] This study showed that all ACA parameters were significantly reduced compared to preoperative values but remained stable throughout the long-term follow-up period, highlighting the importance of maintaining anterior chamber structure and function. In this study, we investigated long-term angle changes after ICL V4c implantation in Chinese patients. Specifically, three years after surgery, the average TIA was 23.59\u0026deg;, and this value remained stable throughout the follow-up period. These results are consistent with the findings of Lin et al.[\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e]who observed similar trends during a six-month follow-up. Changes in anterior chamber angle parameters observed in 62 eyes from 62 patients 6 months post ICL V4c implantation 6 months were consistently lower than preoperative values. Notably, the nasal and temporal ACA (n-ACA and t-ACA) remained stable 1mo after surgery, which aligns with our findings at the 3-year follow-up. Previous evaluations of the postoperative ACA relied predominantly on a local quadrant or single-meridian imaging. In contrast, this study utilized 360-degree global swept-source optical coherence tomography (SS-OCT) automatic scanning to obtain comprehensive three-dimensional data. This approach enables a more thorough assessment of ACA changes and offers valuable guidance for patients with narrow preoperative baseline ACA. Specifically, selecting a smaller-diameter ICL V4c implant may mitigate postoperative complications in such cases.\u003c/p\u003e \u003cp\u003eVault height is a critical parameter for assessing the risk of complications, such as cataracts and glaucoma, following ICL implantation. Vault height typically shows a downward trend, which is associated with the posterior shift of the ICL position.[\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e] It is important to ensure that the vault height remains within a safe range (\u0026ge;\u0026thinsp;0.15 mm), with the ideal range being 0.25\u0026ndash;0.75 mm.[\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e] This study found that the vault heights at 1 day, 1 month, 3 months, and 3 years post-surgery were 0.74\u0026thinsp;\u0026plusmn;\u0026thinsp;0.25 mm, 0.58\u0026thinsp;\u0026plusmn;\u0026thinsp;0.22 mm, 0.54\u0026thinsp;\u0026plusmn;\u0026thinsp;0.2 mm, 0.43\u0026thinsp;\u0026plusmn;\u0026thinsp;0.18 mm, respectively, all within the ideal range. These results suggest that the most significant changes in vault height occur within the first month after surgery, with a relatively gradual downward trend thereafter. Previous studies have also reported a downward trend in vault height both in the short and long term.[\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e, \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e] However, they did not explore the specific factors influencing these changes. In contrast, this study used ACD-L and ACD-ICL to track the positional changes of the lens and ICL, respectively, while controlling for pupil diameter. This study showed that during the follow-up period from 1 d to 3 years after surgery, the ACD-ICL increased, while the ACD-L remained unchanged. This suggests that the ICL moved posteriorly within 1 d after surgery, while the lens position remained stable, leading to a decrease in arch height. This differentiation is clinically significant: it indicates that the vault reduction is not caused by the forward movement of the crystalline lens, thereby implying that the risk of mechanically induced cataract does not increase over the long term.We attribute the posterior shift of the ICL to two factors: first, the position of the ICL loop tends to stabilize and may shift posteriorly over time; second, the ICL loop may compress the soft tissue of the ciliary sulcus, which could eventually lead to adaption or even embedding of the ICL. However, this hypothesis requires further imaging confirmation using UBM (ultrasound biomicroscopy).\u003c/p\u003e \u003cp\u003ePigment dispersion due to contact between the iris and the surface of the artificial lens is a known concern following ICL implantation.[\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e] In this study, during the 3-year follow-up period, it was observed that iris thickness, iris area, and iris volume all showed significant changes 1 d after surgery, but these parameters gradually returned to preoperative baseline values over the subsequent 3 years, with no significant changes noted in long-term follow-up. The changes observed on the first day after surgery may be attributed to surgical manipulation. These results suggest that the structure of the iris remains unaffected by the ICL, indicating that the procedure is both safe and stable. Furthermore, these findings provide evidence that ICL implantation maintains its safety and stability over the long term.\u003c/p\u003e \u003cp\u003eThe primary limitation of this study is its relatively small sample size. However, this limitation is partially mitigated by the use of high-resolution 360-degree swept-source AS-OCT, which provided comprehensive volumetric data (IA, IV, TISA, ARA) rather than simple single-meridian measurements, ensuring the reliability of the longitudinal trends observed. While vault height values exhibited a downward trend over time, long-term changes in the position of the ICL haptics could not be assessed due to the absence of UBM, necessitating further research to confirm these findings. Additionally, the evaluation of parameters such as long-term changes in lens density, may not have been comprehensive. Furthermore, a longer follow-up period could provide greater insights into the dynamic changes in the anterior segment. Future studies should address these limitations by incorporating larger sample sizes, more comprehensive evaluations, and extended follow-up periods.\u003c/p\u003e \u003cp\u003eIn conclusion, this study observed significant anterior segment structural shallowing one day post-surgery, which remained stable over the 3-year follow-up period. The gradual decrease in vault height over time was associated with the posterior shift of the ICL, although the specific mechanisms underlying this trend require further investigation. Despite the absence of postoperative complications, such as elevated IOP or ECD loss, continued long-term follow-up is necessary to monitor anterior segment structural changes in these patients.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eFunding:\u003c/strong\u003e The authors declare that no funds, grants, or other support were received during the preparation of this manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting Interests:\u0026nbsp;\u003c/strong\u003eThe authors declare that they have no competing interests and no financial or proprietary interest in the materials presented herein.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthor Contributions:\u0026nbsp;\u003c/strong\u003eStudy concept and design were performed by Rui Xiong, Zhongjun Tang, Shengtao Liu, and Xingtao Zhou. Data collection was performed by Rui Xiong and Zhongjun Tang. Analysis and interpretation of data were performed by Rui Xiong and Zhongjun Tang. The first draft of the manuscript was written by Rui Xiong and Zhongjun Tang , and critical revision of the manuscript was performed by Xingtao Zhou and Shengtao Liu. Supervision was provided by Xingtao Zhou and Shengtao Liu. All authors read and approved the final manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEthics Approval:\u0026nbsp;\u003c/strong\u003eThis study was performed in line with the principles of the Declaration of Helsinki. Approval was granted by the Ethics Committee of Fudan University, Shanghai.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent to Publish:\u0026nbsp;\u003c/strong\u003eNot applicable.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eData Availability:\u003c/strong\u003e The datasets generated during and/or analyzed during the current study are available from the corresponding author on reasonable request.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent to Participate:\u003c/strong\u003e Written informed consent was obtained from all individual participants included in the study.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eIgnacio FVJ, Ana MM, Joaqu\u0026iacute;n FF et al (2016) Computational study of aqueous humor dynamics assessing the vault and the pupil diameter in two posterior-chamber phakic lenses. Invest Ophthalmol Vis Sci 57:4625\u0026ndash;4631.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eIgarashi A (2019) Posterior chamber phakic IOLs vs. LASIK: Benefits and complications. Expert Rev Ophthalmol 14:43\u0026ndash;52.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eFern\u0026aacute;ndez-Vega-Cueto L, Alfonso-Bartolozzi B, Lisa C et al (2021) Seven-year follow-up of posterior chamber phakic intraocular lens with central port design. Eye Vis (Lond) 8:23.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eYang W, Zhao J, Sun L et al (2021) Four-year observation of the changes in corneal endothelium cell density and correlated factors after Implantable Collamer Lens V4c implantation. Br J Ophthalmol 105:625\u0026ndash;630.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eIgarashi A, Kamiya K, Ichikawa K et al (2022) Multicenter clinical outcomes of hole implantable collamer lens implantation in middle-aged patients. Sci Rep 12:4236.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBoliang L, Xun C, Mingrui C et al (2023) Long-term vault changes in different levels and factors affecting vault change after implantation of implantable collamer lens with a central hole. Ophthalmol Ther 12:499\u0026ndash;512.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHaiting C, Guangzeng N, Yuxiang F, Jingxue M (2016) Comparison of intraocular pressure and vault after implantation of implantable collamer lens with and without a central hole. BMC Ophthalmol 16:203.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAlonso-Ju\u0026aacute;rez E, Vel\u0026aacute;zquez-Villoria D (2022) Low diopter phakic implantable collamer lens: Refractive and visual outcomes in low myopia and myopic astigmatism. Clin Ophthalmol 16:2969\u0026ndash;2977.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eBhandari V, Karandikar S, Reddy JK, Relekar K (2015) Implantable collamer lens V4b and V4c for correction of high myopia. J Curr Ophthalmol 27:76\u0026ndash;81.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eChen X, Wang X, Xu Y et al (2021) Five-year outcomes of EVO implantable collamer lens implantation for the correction of high myopia and super high myopia. Eye Vis (Lond) 8:40.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAlfonso JF, Fern\u0026aacute;ndez-Vega-Cueto L, Alfonso-Bartolozzi B et al (2019) Five-year follow-up of correction of myopia: Posterior chamber phakic intraocular lens with a central port design. J Refract Surg 35:169\u0026ndash;176.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLi HM, Nie DJ, Zhong B et al (2023) Efficacy of implantable collamer lens V4c implantation in the treatment of high myopia. Int Eye Sci 23:1409\u0026ndash;1412.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eChen X, Shen Y, Xu H et al (2020) One-year natural course of corneal densitometry in high myopic patients after implantation of an implantable collamer lens (model V4c). BMC Ophthalmol 20:50.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eZhao J, Zhao J, Yang W et al (2021) Peripheral anterior chamber depth and angle measurements using Pentacam after implantation of toric and non-toric implantable collamer lenses. Front Med (Lausanne) 8:610590.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMoghimi S, Bijani F, Chen R et al (2018) Anterior segment dimensions following laser iridotomy in acute primary angle closure and fellow eyes. Am J Ophthalmol 186:59\u0026ndash;68.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLin Q, Yang D, Zhou X (2022) Early outcomes of anterior segment parameters after implantable collamer lens V4c implantation. BMC Ophthalmol 22:429.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eYuhao Y, Jing Z, Lingling N et al (2022) Long-term evaluation of anterior lens density after implantable collamer lens V4c implantation in patients with myopia over 40 years old. Br J Ophthalmol 106:1523\u0026ndash;1529.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eCerpa Manito S, S\u0026aacute;nchez Tranc\u0026oacute;n A, Torrado Sierra O et al (2021) Biometric and ICL-related risk factors associated to sub-optimal vaults in eyes implanted with implantable collamer lenses. Eye Vis (Lond) 8:26.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGarcia-De la Rosa G, Olivo-Payne A, Serna-Ojeda JC et al (2018) Anterior segment optical coherence tomography angle and vault analysis after toric and non-toric implantable collamer lens V4c implantation in patients with high myopia. Br J Ophthalmol 102:544\u0026ndash;548.\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"international-ophthalmology","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"inte","sideBox":"Learn more about [International Ophthalmology](https://www.springer.com/journal/10792)","snPcode":"10792","submissionUrl":"https://submission.nature.com/new-submission/10792/3","title":"International Ophthalmology","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"high myopia, anterior segment structure, long-term, ICL V4c","lastPublishedDoi":"10.21203/rs.3.rs-8849855/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-8849855/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003ePurpose\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eTo evaluate the long-term outcomes of anterior segment parameters following implantable collamer lens (ICL V4c) implantation in highly myopic patients.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eSetting\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eA tertiary specialized eye hospital in Shanghai, China.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eDesign\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eProspective, non-randomized, consecutive case series.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMethods\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis study included 32 eyes of 20 patients with high myopia who underwent ICL V4c implantation with a 3-year follow-up. Preoperative assessments included standard biometry and anterior segment parameters. Postoperative evaluations were conducted at 1 day, 1 month, 3 months, and 3 years. Parameters assessed included corneal endothelium-anterior capsule distance (ACD-L), corneal endothelium-ICL distance (ACD-ICL), ICL-anterior capsule distance (ICL-L), anterior chamber angle (ACA) parameters, and iris metrics.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eResults\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eACD-L decreased significantly postoperatively (P \u0026lt; 0.001) but remained stable thereafter. ACD-ICL increased over time, while ICL-L (vault) decreased significantly (P \u0026lt; 0.001), with the most pronounced changes occurring in the first month. All ACA parameters (ACW, AOD500, ARA500, TISA500, TIA500) decreased significantly compared to preoperative values (all P \u0026lt; 0.001) but showed no significant differences among postoperative follow-up points (P \u0026gt; 0.05). Iris parameters (IA, IV) showed transient changes at 1 day post-surgery but returned to baseline levels thereafter.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConclusions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eICL V4c implantation demonstrated safety and efficacy during the valuable 3-year follow-up. While the anterior chamber angle narrowed and vault height decreased initially, the anterior segment structure remained stable over the long term. Crucially, the vault decrease was primarily driven by a posterior shift of the ICL rather than an anterior shift of the crystalline lens, confirming the long-term safety regarding cataract formation.\u003c/p\u003e","manuscriptTitle":"Long-term evaluation of anterior segment structures after implantable collamer lens V4c implantation","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2026-04-20 17:23:45","doi":"10.21203/rs.3.rs-8849855/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"editorInvitedReview","content":"","date":"2026-04-15T02:00:19+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"203010192748580676752536819989596795389","date":"2026-04-15T01:17:38+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2026-04-13T10:17:05+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2026-02-14T07:29:02+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2026-02-14T07:27:38+00:00","index":"","fulltext":""},{"type":"submitted","content":"International Ophthalmology","date":"2026-02-11T09:12:21+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"international-ophthalmology","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"inte","sideBox":"Learn more about [International Ophthalmology](https://www.springer.com/journal/10792)","snPcode":"10792","submissionUrl":"https://submission.nature.com/new-submission/10792/3","title":"International Ophthalmology","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"3bd158bc-6ef0-4646-a7b3-beae891216f1","owner":[],"postedDate":"April 20th, 2026","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[],"tags":[],"updatedAt":"2026-04-20T17:23:51+00:00","versionOfRecord":[],"versionCreatedAt":"2026-04-20 17:23:45","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-8849855","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-8849855","identity":"rs-8849855","version":["v1"]},"buildId":"XKTyCvWXoU3ODBz1xrDgd","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}