Visual outcomes of Visian ICL implantation for high myopia in patients with shallow anterior chamber depth

Clinical Observation of Posterior-Chamber Phakic Implantable Collamer Lens V4c Implantation in Myopic Patients with Shallow Anterior Chamber Depth: A Retrospective, Consecutive Observational Study

Purpose

The reference range for the preoperative anterior chamber angle width for ICL surgery is unclear. Our objective was to assess the clinical effect and the range of anterior chamber angle width of posterior-chamber implantable collamer lens V4c (ICL V4c) implantation in patients with anterior chamber depth (ACD) < 2.8 mm.

Methods

Patients who underwent ICL V4c implantation with shallow ACD were included in this retrospective study. The patients' uncorrected and corrected distance visual acuity, angle of trabecular-iris (TIA), angle-opening distance (AOD500), trabecular-iris space area (TISA500), corneal endothelial cell density, vault, retinal nerve fiber layer thickness, intraocular pressure, visual field, and complications were analyzed.

Results

Forty-one patients (68 eyes) completed at least 12 months of follow-up (median follow-up, 30 months). The effectiveness and safety indices were 1.09 ± 0.13 and 1.04 ± 0.21, respectively. The preoperative TIA values on the nasal and temporal sides were 39.78 ± 7.68 degree (range, 25.8-65.1 degree) and 41.54 ± 8.03 degree (range, 28.5-63.00 degree). Forty-seven eyes had uncorrected distance visual acuity ≥1.0, and 55 had corrected distance visual acuity ≥1.0 at the last follow-up visit. The TIA, AOD500, and TISA500 on the nasal and temporal sides were significantly reduced compared to those before surgery (all P < 0.01); no eye had an angle closure or elevated intraocular pressure. The ICL V4c vault was 290.88 ± 153.36 μm (range, 60.0-880.0 μm). No severe complications occurred in any patient.

Conclusions

In patients with myopia with shallow ACD (2.55-2.79 mm), a preoperative TIA >25.8° is safe and effective for a relatively long time after surgery; however, an extended long-term close follow-up is needed.

Endothelial cell loss post-implantable collamer lens V4c: meta-analysis

Endothelial cell density (ECD) loss is a noted effect of implantable collamer lens (ICL) V4c surgery. Current literature provides a wide range of values for ECD loss postsurgery, which may not be helpful in advising patients and clinicians. A meta-analysis exploring ECD loss in ICL V4c for myopia correction was undertaken. 18 studies were included in this meta-analysis with 2 subgroup analyses to account for the variability in follow-up lengths. The average ECD loss 3 months, 12 months, and 21.25 (mean) months postsurgery were 1.32% ± 1.28% ( P < .001, 95% CI, -75.158 to -1.19), 1.75% ± 2.17% ( P < .001, 95% CI, -134.09 to 14.52), and 3.84% ± 1.78% ( P < .001, 95% CI, -156.04 to -54.26), respectively. ECD loss is most pronounced 3 months postsurgery, suggesting that acute surgical trauma was the primary contributor rather than long-term lens implantation. Overall, ICL V4c is for myopia correction exhibits similar ECD loss as seen in other ICL models, thereby affirming its safety.

Rhegmatogenous retinal detachment in highly myopic eyes with implantable collamer lens

AIM

To investigate the clinical characteristics, treatment methods and outcomes of rhegmatogenous retinal detachment (RRD) in highly myopic eyes with implantable collamer lens (ICL).

METHODS

High myopia patients who received treatment for nontraumatic RRD after ICL implantation surgery at the Retinal Department of Zhongshan Ophthalmic Center from Jan 2018 to Dec 2022 were reviewed. Comprehensive ophthalmologic examinations including visual acuity measurement and digital fundus photography were performed in each patient.

RESULTS

A total of nine RRD eyes from nine patients who received V4c-ICL implantation were included. The mean time from ICL implantation surgery to the diagnosis of RRD was 32.44±22.56mo (range, 1-60mo). At the initial visit for RRD, giant retinal tear (GRT), horseshoe tear, simple round hole, and horseshoe tear combined with round hole were detected in 3, 3, 2, and 1 eye(s), respectively, with macula-off in eyes. Eight patients received surgical treatment, and one patient was treated by retinal laser photocoagulation alone. The ICL was preserved in 7 eyes. At the last follow-up, the mean best corrected visual acuity (BCVA) improved significantly from 1.76±1.06 logMAR at presentation to 0.81±1.01 logMAR (P=0.035), and no case of recurrent retinal detachment was found.

CONCLUSION

The morphological presentation of retinal breaks is diverse in this study. The ICL can be preserved in most cases during the course of retinal detachment repair surgery in our data, companied with acceptable visual and anatomical outcomes.

Endothelial Cell Loss in Patients with Phakic Intraocular Lenses

Although the safety of phakic intraocular lenses (pIOLs) has been continuously improved over 70-years of development, high endothelial cell losses can occur even with current pIOL models. Numerous studies have demonstrated that the distance of a pIOL to the corneal endothelium plays a crucial role in the extent of endothelial cell loss. For this reason alone, higher endothelial cell loss tends to be observed with anterior chamber lenses than with posterior chamber lenses. Adequate preoperative anterior chamber depth is essential, at least for iris-fixed pIOLs, in order to ensure a safe distance from the endothelium. However, the anterior chamber becomes shallower with age and therefore it may be useful to consider patient age in the safety criteria. Although endothelial cell loss is generally low with current pIOL models, regular monitoring of the endothelial cell density remains essential due to large interindividual differences in patients with pIOLs. If the endothelial cell loss is greater than expected and the follow-up visits confirm the trend, the pIOL should be explanted without delay. The endothelial reserve should be considered on an individual basis by taking into account patient age, physiological endothelial cell loss, and loss due to further surgery. With careful indication and long-term patient care, pIOLs remain a safe treatment option.

Five-year follow-up of a posterior chamber phakic intraocular lens with a central hole for correction of myopia

PURPOSE

To evaluate intermediate and long-term visual outcomes and safety of a phakic intraocular posterior chamber lens with a central hole (ICL V4c) for myopic eyes.

METHODS

Retrospective, consecutive case study of patients that uneventfully received a ICL V4c for myopia correction, with a 5-year postoperative follow-up. Department of Ophthalmology, Goethe University Frankfurt, Germany.

RESULTS

From 241 eyes that underwent ICL implantation, we included 45 eyes with a mean age at surgery of 33 years ± 6 (18-48 years), with a 5 years follow-up. CDVA improved from 0.05logMAR ± 0.15 CDVA preoperatively to  - 0.00 ± 0,07 at 5 years and did not change significantly from 3 to 5 years' time (p = 0.266). The mean spherical equivalent (SE) improved from -10.13D ± 3.39 to  - 0.45D ± 0.69. The change in endothelial cell count showed a mean decrease of 1.9% per year throughout the follow-up. Safety and efficacy index were 1.16 and 0.78, respectively. Cataract formation was seen in 2 of 241 eyes (0.8%), but in none of the 45 eyes that finished the 5-year follow-up.

CONCLUSIONS

Our data show a good intermediate and long-term stability, efficiency, and safety of ICL V4c phakic lenses in myopic eyes comparable to other known literature.

Exploring Nomograms for Implantable Collamer Lens Size Selection in Myopia: A Literature-based Compilation

Purpose

To provide a comprehensive guide of all implantable collamer lens (ICL) sizing nomograms and the respective preoperative diagnostic devices that are required. This guide would help clinicians in choosing the appropriate ICL size for myopic patients to optimize postoperative vault height.

Methods

A literature search of peer-reviewed journals describing methods and postoperative outcomes of ICL sizing was conducted. Research articles containing ICL nomograms or formulas were identified from this search. Preoperative variables necessary for these nomograms and the required diagnostic devices to measure these parameters such as topography, biometry, or ultrasound biomicroscopy (UBM) were noted. An additional search was conducted to identify artificial intelligence (AI) or machine learning (ML)-derived nomograms.

Results

Eighteen ICL sizing nomograms were identified through literature search. Five of these nomograms are available for use and require topography or biometry devices. Of these, four include the manufacturer's, optimized white-to-white (WTW), Kang, Kim, and Rocamora Nomograms. Eight of the 18 nomograms available for use require UBM. Eight of these include the Kojima, Nakamura, KS, ZZ, Dougherty, Parkhurst, Russo, and Reinstein Nomograms. Four of the 18 nomograms are ML-derived including Shen, Rocamora, Russo, and Kang Nomograms.

Conclusion

ICL nomograms are a vital tool in helping clinicians select the right ICL size for myopic patients to optimize postoperative vault reducing risk of postoperative complications. Based on available diagnostic devices such as topography, biometry, or UBM clinicians can integrate specific nomograms into practice.

Efficacy and Safety of Implantable Collamer Lens V4c Implantation in 1,834 Myopic Eyes for 1 Year of Follow-up

PURPOSE

To evaluate visual outcomes of patients with myopia after EVO Implantable Collamer Lens (ICL) (STAAR Surgical) implantation and predict risk factors of postoperative vault abnormalities.

METHODS

In this single-center, retrospective analysis, 1,834 eyes of 926 patients with myopia who underwent EVO ICL implantation were recruited between 2020 and 2021. Patients were followed up for 1 year, during which surgery outcomes were evaluated. In addition, 31 eyes with vault abnormalities who underwent secondary surgery were enrolled to form a generalized linear model, which aimed to predict risk factors contributing to vault abnormalities.

RESULTS

At the final follow-up visit, safety and efficacy indexes were 1.12 ± 0.17 and 1.10 ± 0.19, respectively, and there was no statistical significance between the low and high myopia groups. Furthermore, 79.18% of eyes achieved a residual spherical equivalent within ±0.50 diopters. Except for the temporary elevation of intraocular pressure at 1 week postoperatively, IOP and endothelial cell density remained stable during follow-up visits. The rate of postoperative adverse events was 21.97% and most adverse events were transient. Vault abnormalities accounted for the majority of complications (9.54%). Results of generalized linear model showed that age was a risk factor for postoperative vault abnormalities, and the anterior chamber depth served as a protective factor (P < .05).

CONCLUSIONS

Visual outcomes of EVO ICL implantation were satisfactory in safety and efficacy indexes in both the low and high myopia groups for 1 year of follow-up, with acceptable stability in postoperative spherical equivalent, intraocular pressure, and endothelial cell density. This study emphasized cautious ICL size selection for older patients and those with shallow anterior chamber depth. [J Refract Surg. 2023;39(10):694-704.].

Diagnostic Techniques to Increase the Safety of Phakic Intraocular Lenses

Preoperative and postoperative diagnostics play an important role in ensuring the safety of patients with phakic intraocular lenses (pIOLs). The risk of endothelial cell loss can be addressed by regularly measuring the endothelial cell density using specular microscopy and considering the endothelial cell loss rate and the endothelial reserve in accordance with the patient's age when deciding whether to explant a pIOL. The anterior chamber morphometrics, including the anterior chamber depth and the distance between the pIOL and the endothelium, measured using Scheimpflug tomography and anterior segment optical coherence tomography (AS-OCT), can help to assess the risk of the endothelial cell loss. In patients undergoing posterior chamber pIOL implantation, accurate prediction of the vault and its postoperative measurements using AS-OCT or Scheimpflug tomography are important when assessing the risk of anterior subcapsular cataract and secondary glaucoma. Novel approaches based on ultrasound biomicroscopy and AS-OCT have been proposed to increase the vault prediction accuracy and to identify eyes in which prediction errors are more likely. Careful patient selection and regular postoperative follow-up visits can reduce the complication risk and enable early intervention if a complication occurs.

Anterior segment structure changes caused by different luminance light after implantable collamer lens surgery

BACKGROUNDS

To investigate the changes of anterior eye segment with implantable collamer lens (ICL) under mesopic and photopic conditions.

METHOD

Forty-seven eyes of myopic patients who underwent ICL V4c implantation were included. Three months after surgery, the pupil diameter (PD), dynamic vault, ACD (distance from the posterior corneal surface to the anterior lens surface), ACD-ICL (distance from the posterior corneal surface to the anterior ICL surface), and anterior chamber angle parameters were measured using the anterior segment optical coherence tomography (AS-OCT, Carl Zeiss AG, Germany) under completely mesopic (0 lx) and photopic (5290 lx) lighting conditions.

RESULTS

Compared with mesopic conditions, a significant decreased vault was detected in photopic conditions (486.7 ± 186.1 μm versus 643.5 ± 191.2 μm, p < 0.001), while the ACD-ICL increased significantly (2.54 ± 0.24 mm versus 2.37 ± 0.23 mm, p < 0.001). The pupil was smaller in photopic condition (2.66 ± 0.23 mm versus 5.62 ± 0.55 mm, p < 0.001). ACD didn't change(3.32 ± 0.24 mm versus 3.31 ± 0.22 mm, p = 0.079). The change of the vault was positively related to the changes of the PD (r² = 0.301, p = 0.04). There were no statistical difference between the change of vault and the change of ACD-ICL (158.0 ± 58.1 μm versus 165.9 ± 65.3 μm, p = 0.320).

CONCLUSION

When exposed to high intensity light after ICL surgery, the pupil constricted, vault decreased, ACA widened and ACD-ICL increased. All these changes were caused by the change of iris not the crystalline lens.

Automatic measurement of anterior chamber angle parameters in AS-OCT images using deep learning

The early assessment of angle closure is of great significance for the timely diagnosis and treatment of primary angle-closure glaucoma (PACG). Anterior segment optical coherence tomography (AS-OCT) provides a fast and non-contact way to evaluate the angle close using the iris root (IR) and scleral spur (SS) information. The objective of this study was to develop a deep learning method to automatically detect IR and SS in AS-OCT for measuring anterior chamber (AC) angle parameters including angle opening distance (AOD), trabecular iris space area (TISA), trabecular iris angle (TIA), and anterior chamber angle (ACA). 3305 AS-OCT images from 362 eyes and 203 patients were collected and analyzed. Based on the recently proposed transformer-based architecture that learns to capture long-range dependencies by leveraging the self-attention mechanism, a hybrid convolutional neural network (CNN) and transformer model to encode both local and global features was developed to automatically detect IR and SS in AS-OCT images. Experiments demonstrated that our algorithm achieved a significantly better performance than state-of-the-art methods for AS-OCT and medical image analysis with a precision of 0.941, a sensitivity of 0.914, an F1 score of 0.927, and a mean absolute error (MAE) of 37.1±25.3 µm for IR, and a precision of 0.805, a sensitivity of 0.847, an F1 score of 0.826, and an MAE of 41.4±29.4 µm for SS, and a high agreement with expert human analysts for AC angle parameter measurement. We further demonstrated the application of the proposed method to evaluate the effect of cataract surgery with IOL implantation in a PACG patient and to assess the outcome of ICL implantation in a patient with high myopia with a potential risk of developing PACG. The proposed method can accurately detect IR and SS in AS-OCT images and effectively facilitate the AC angle parameter measurement for pre- and post-operative management of PACG.

Long-term results of a new posterior chamber phakic intraocular lens in patients with high myopia: 5-year results

PURPOSE

To evaluate the long-term refractive outcomes of Eyecryl posterior chamber spherical phakic intraocular lens (pIOL) implantation in high myopia and endothelial cell density (ECD) change.

SETTING

Beyoglu Eye Training and Research Hospital, Istanbul, Turkey.

DESIGN

Retrospective.

METHODS

Eyes that were not suitable for corneal refractive surgery, had high myopia between -6.00 diopters (D) and -20.00 D, had Eyecryl posterior chamber spherical pIOL implantation, and had at least 5 years of follow-up were included. Preoperative ECD was ≥2300 cells/mm 2 and cylindrical value was ≤2.0 D in all cases. Preoperative and postoperative first, third, and fifth years of refraction, uncorrected and corrected distance visual acuity (UDVA/CDVA), and ECD were recorded.

RESULTS

36 eyes of 18 patients were examined. The mean UDVA and CDVA in postoperative fifth years were 0.24 ± 0.19 logMAR and 0.12 ± 0.18 logMAR, respectively. The safety and efficacy indices were 1.52 ± 0.54 and 1.14 ± 0.38, respectively. At 5 years, the spherical equivalent was ±0.50 D in 75% of eyes and ±1.00 D in 92% of eyes. After 5 years, the mean cumulative ECD loss was 6.91% ( P = .07). The annual ECD loss was 1.57% in the first year, 0.26% between 1 year and 3 years, and 2.38% between 3 years and 5 years. Asymptomatic anterior capsule opacity developed in 1 eye 4 years after surgery. Rhegmatogenous retinal detachment developed in 1, and myopic choroidal neovascular membrane occurred in 1 eye.

CONCLUSIONS

Eyecryl posterior chamber spherical pIOL implantation is one of the effective and safe refractive surgical methods in correcting high myopia with predictable and stable refractive results over a 5-year period. Longer-term studies are needed for complications such as decreased ECD, retinal complications, and lens opacity.

Anterior Segment Characteristics of Eyes with Anterior Chamber Depth Less than 2.8 mm and Axial Length Greater than 25 mm

INTRODUCTION

This study aimed to investigate anterior segment parameters of eyes, with anterior chamber depth (ACD) less than 2.8 mm and axial length greater than 25.0 mm.

METHODS

This cross-sectional study included 180 myopic eyes of 180 consecutive patients with axial length greater than 25.0 mm. Patients were divided into low ACD (ACD < 2.8 mm, n = 56) and normal ACD (ACD ≥ 2.8 mm, n = 124) groups. Anterior segment parameters were measured using Scheimpflug imaging and ultrasound biomicroscopy. A general linear model was used to compare parameters between the two groups, after adjusting for age and spherical equivalent.

RESULTS

Compared with the normal ACD group, the low ACD group had lower values for the following parameters: corneal diameter, trabecular-anterior iris surface angle, angle-opening distance at 500 μm, anterior chamber volume, anterior chamber width, anterior vault, iris thickness at 500 μm, ciliary sulcus-to-sulcus diameter, distance between cornea and sulcus, trabecular-ciliary process distance, maximum ciliary body thickness, ciliary process length, relative anterior vault, relative distance between cornea and sulcus, and relative lens position (general linear model, p < 0.05). In contrast, central corneal thickness, iris curvature, lens thickness, lens vault, and iris-ciliary angle were greater in the low ACD group (general linear model, p < 0.05).

CONCLUSION

A smaller anterior segment, as well as a thicker and more anteriorly positioned lens, may correlate with shallow ACD in eyes with long axial length.

Predicting Postoperative Anterior Chamber Angle for Phakic Intraocular Lens Implantation Using Preoperative Anterior Segment Metrics

Purpose

The anterior chamber angle (ACA) is a critical factor in posterior chamber phakic intraocular lens (EVO Implantable Collamer Lens [ICL]) implantation. Herein, we predicted postoperative ACAs to select the optimal ICL size to reduce narrow ACA-related complications.

Methods

Regression models were constructed using pre-operative anterior segment optical coherence tomography metrics to predict postoperative ACAs, including trabecular-iris angles (TIAs) and scleral-spur angles (SSAs) at 500 µm and 750 µm from the scleral spur (TIA500, TIA750, SSA500, and SSA750). Data from three expert surgeons were assigned to the development (N = 430 eyes) and internal validation (N = 108 eyes) datasets. Additionally, data from a novice surgeon (N = 42 eyes) were used for external validation.

Results

Postoperative ACAs were highly predictable using the machine-learning (ML) technique (extreme gradient boosting regression [XGBoost]), with mean absolute errors (MAEs) of 4.42 degrees, 3.77 degrees, 5.25 degrees, and 4.30 degrees for TIA500, TIA750, SSA500, and SSA750, respectively, in internal validation. External validation also showed MAEs of 3.93 degrees, 3.86 degrees, 5.02 degrees, and 4.74 degrees for TIA500, TIA750, SSA500, and SSA750, respectively. Linear regression using the pre-operative anterior chamber depth, anterior chamber width, crystalline lens rise, TIA, and ICL size also exhibited good performance, with no significant difference compared with XGBoost in the validation sets.

Conclusions

We developed linear regression and ML models to predict postoperative ACAs for ICL surgery anterior segment metrics. These will prevent surgeons from overlooking the risks associated with the narrowing of the ACA.

Translational Relevance

Using the proposed algorithms, surgeons can consider the postoperative ACAs to increase surgical accuracy and safety.

Vault-Correlated Efficacy and Safety of Implantable Collamer Lens V4c Implantation for Myopia in Patients with Shallow Anterior Chamber Depth

INTRODUCTION

The aim of the study was to evaluate efficacy and safety outcomes after implantation of the Visian Implantable Collamer Lens (ICL V4c) in myopia patients with shallow anterior chamber depth (ACD).

METHODS

This retrospective study followed 163 eyes of 94 patients for at least 24 months. Uncorrected distance visual acuity (UDVA), corrected distance visual acuity, intraocular pressure (IOP), manifest refraction, vault, endothelial cell density (ECD), anterior chamber angle (ACA), anterior chamber volume, and the distance from the corneal endothelium to the central ICL (C-ICL) were measured during follow-ups. Spearman's correlation and logistic regression were used to identify variables correlated with changes in ECD and potential risk factors for ineffective outcomes, respectively.

RESULTS

All surgeries were performed safely. High IOP of 9 eyes and anterior capsular opacity of 5 eyes were observed. The last follow-up ACA had a significant difference between the high and normal IOP groups (p = 0.0003). The mean ECD and vault were 2,855.76 ± 270.82 cells/mm2 and 388.01 ± 135.28 μm at the last follow-up, respectively. The vault and C-ICL were significantly associated with ΔECD (all p < 0.05). Furthermore, the vault was most responsible for the ECD loss. Twenty-two eyes had unsatisfactory postoperative UDVA, and the low vault at the last follow-up was a significant risk factor for this ineffective outcome (p < 0.001, OR = 14.739).

CONCLUSIONS

ICL V4c implantation in patients with shallow ACD achieved stable visual outcomes. The vault is related to postoperative visual acuity and ECD loss, which needs to be paid attention during follow-up.

Evaluation of Higher Order Aberrations and Anterior Segment Parameters Changes After Implantable Collamer Lens Implantation for High Myopia

Purpose

To evaluate changes in higher order aberrations (HOAs) induced by implantable collamer lens (ICL) implantation in correction of high myopia and to compare the anterior segment parameters before and after surgery. Also, to correlate these parameters with HOAs, the best corrected visual acuity (BCVA) and intraocular pressure (IOP).

Methods

This prospective interventional cohort case series study included 40 eyes with high myopia that underwent ICL V4c implantation. They were evaluated pre-operatively and post-operatively at 1^st and 3^rd month HOAs using Scheimpflug Sirius Camera. The anterior segment parameters were evaluated by optical biometry. Correlations between HOAs, BCVA and anterior segment parameters were evaluated.

Results

The mean pre-operative BCVA was 0.67 ± 0.17, while post-operative BCVA was 0.74 ± 0.16 (p-value < 0.001). The spherical equivalent was -13.66 ± 2.23 pre-operatively, while post-operatively it was -0.77 ± 0.65 (p-value < 0.001). The mean pre-operative root mean square (RMS) of HOAs was 0.62 ± 0.11 µm, while mean post-operative RMS in the 1st month was 0.82 ± 0.29 µm (p-value < 0.001). At 3rd month, it was 0.63 ± 0.17 µm (p-value = 0.685). The mean pre-operative anterior chamber depth (ACD) was 3.66 ± 0.26 mm. It decreased in the post-operative 1^st month to 3.46 ± 0.30 mm, while in 3^rd month 3.45 ± 0.24 mm (p-value < 0.001, < 0.001) respectively. The mean pre-operative anterior chamber angle (ACA) 45.98 ± 8.39 ^o while, the mean ACA was 31.65 ± 4.14, 31.03 ± 3.74 post-operatively (p-value < 0.001, < 0.001) respectively. There was significant increase in IOP (p-value < 0.001).

Conclusion

ICL implantation is safe and effective in correction of high myopia, as HOAs increase at first month post-operatively then, return to the pre-operative level by 3^rd month. However, anterior segment parameters show significant changes which may need longer follow up.

Validation of the vault prediction model based on the sulcus-to-sulcus diameter and lens thickness: a 925-eye prospective study

BACKGROUND

To verify the accuracy and stability of the prediction formula based on the ciliary sulcus diameter and lens thickness and to analyse factors influencing the prediction results.

METHODS

In total, 925 eyes from 506 subjects were enrolled in this prospective study between July 1, 2020, and June 30, 2021. Subjects were divided into four seasons, each spanning three months. The target vault was set to be between 300 μm and 700 μm according the prediction formula. The actual vault was measured one month postoperatively. The Bland-Altman test, 95% confidence intervals (95% CI) and 95% limits of agreement (95% LoA) were used to evaluate the agreement between the predicted vault and the actual vault. Eyes with absolute prediction errors greater than 300 μm were further analysed.

RESULTS

The mean predicted vaults for the four seasons were 503 ± 99, 494 ± 96, 481 ± 92 and 502 ± 93 μm, while the mean actual vaults were 531 ± 189, 491 ± 179, 464 ± 179 and 529 ± 162 μm, respectively. The predicted and actual vaults of the overall subjects were 493 ± 95 and 500 ± 180 μm, respectively. Of the 925 eyes, 861 eyes (93.08%), 42 eyes (4.54%), and 22 eyes (2.38%) showed a normal vault, high vault, and low vault, respectively. Bland-Altman plots showed that the mean difference between the actual vault and predicted vault overall (± 95% LoA) was 6.43 ± 176.2 μm (-339 to 352 μm). Three UBM features may lead to large prediction errors (more than 300 μm): wide iris-ciliary angle (ICA), iris concavity and anteriorly positioned ciliary body.

CONCLUSIONS

This study demonstrated the accuracy and stability of the prediction formula through the validation of a large sample size and a long time span. Wide ICA, iris concavity and anteriorly positioned ciliary body may have an effect on vault.

Vault differences in eyes implanted with spherical and toric implantable collamer lenses: an inter-eye analysis

Purpose

To determine the influence of implantable collamer lenses (ICL) geometry, i.e. spherical and toric on the vault, and report the refractive and visual outcomes of patients bilaterally implanted with the two ICL geometries.

Methods

This retrospective case series analysed 41 patients implanted with a spherical ICL (sICL) in one eye and an equal sized toric ICL (tICL) in the fellow eye. The anatomical and ICL-related parameters were assessed using anterior-segment optical coherence tomography (AS-OCT Visante, Zeiss Meditec AG) and optical tomography (Pentacam, OCULUS). The influence of the anatomical and ICL-related parameters on the vault was determined using generalised estimating equations (GEE) to incorporate inter-eye correlations.

Results

Postoperative spherical equivalent was within ± 0.50D in 66% and 83% of the eyes, respectively implanted with sICL and tICL. The efficacy index in the sICL group was 1.06 and 1.14 in the tICL group. The mean inter-eye vault difference was -1.46 µm, anatomical and ICL-related parameters showed similar associations with the vault for sICL and tICL. The GEE identified the ICL size minus the anterior chamber width, the ICL spherical power and ICL central thickness as significant factors influencing the vault.

Conclusions

Spherical and toric ICL showed good efficacy for the correction of myopia and astigmatism. Patients implanted bilaterally with sICL and tICL tend to present similar vaults. The vault produced by both types of ICL was mainly regulated by the oversizing of the ICL. This suggests that the ICL geometry (spherical vs toric) is a factor with limited influence on the vault, thus the sizing method of a sICL and tICL should be similar.

Early outcomes of anterior segment parameters after implantable collamer lens V4c implantation

Background

This study investigated the early outcomes of anterior segment parameters after implanting an implantable collamer lens with a central hole (ICL V4c) in patients with myopia and determined the earliest follow-up time for detecting potential complications.

Methods

Sixty-two patients were included, and the following parameters were measured at baseline (preoperative), 1 day, 1 week, and 1, 3, and 6 months after the operation: intraocular pressure (IOP), endothelial cell density (ECD), central anterior chamber depth (CACD), anterior chamber volume (ACV), nasal and temporal anterior chamber angle (n-ACA and t-ACA), horizontal corneal diameter (white-to-white, WTW), and axial length (AL). The vault was measured at each post-operative timepoint.

Results

The postoperative IOP and ECD at the 6 months were both statistically similar to the baseline. The post-operative CACD and ACV were significantly less at all timepoints compared with the baseline (P < 0.001) and stayed stable from 1 day and 1 month after the operation, respectively. Postoperative n-ACA and t-ACA decreased significantly at 1 day and 1 week compared with the baseline (P < 0.001), while tended to stabilization at 1, 3, and 6 months. The vault kept decreasing significantly at 1 day, 1 week, and 1 month, but stayed stable at 3 and 6 months. The postoperative n-ACA and t-ACA positively correlated with the baseline ACA, CACD, and ACV.

Conclusions

The anterior chamber parameters tended to stabilization early after the operation. Thus, it is essential to evaluate patients’ anterior segment status at earlier timepoints and prevent complications with prompt and non-invasive intervention.

Efficacy and safety after posterior chamber Implantable Collamer Lens implantation according to preoperative anterior chamber depth: Short-term comparative study

PURPOSE

To compare visual, refractive, and safety outcomes of posterior chamber Implantable Collamer Lens (ICL) implantation for the correction of myopia according to the preoperative anterior chamber depth (ACD).

METHODS

Retrospective, comparative study, patients submitted to implantation of myopic posterior-chamber phakic Implantable Collamer Lens (ICL), model V4C/V5, minimum follow-up of 12 months; two groups were created: Group 1 (ACD 2.80 to 2.99 mm) and Group 2 (ACD equal to or greater than 3.00 mm). The parameters evaluated were uncorrected and corrected visual acuity, subjective refraction, efficacy and safety index, predictability, endothelial cell density, central vault, anterior chamber angle and postoperative complications. A total of 558 eyes from 298 patients were evaluated: 111 eyes (19.9%) in group 1 and 447 eyes (80.1%) in group 2.

RESULTS

At 12 months, the efficacy index was similar in both groups (p = 0.264); the safety index was higher in group 1 (p = 0.031); the mean central Vault was significantly lower in group 1 (212.8 vs 410.6 μm; p < 0.001). Respectively, 93 (83.8%) and 366 (84.1%) eyes were within ±0.50 D of targeted refraction. Anterior chamber angle significantly decreased during follow-up in both groups (p < 0.001; p < 0.001). Intraocular pressure did not change significantly (p = 0.310 and p = 0.446, respectively). There were no significant differences in endothelial cell density loss (p = 0.278) or in the rate of complications observed (p = 0.733).

CONCLUSIONS

ICL implantation is an effective and safe procedure in eyes with shallow anterior chambers, with visual and refractive results and complication rates identical to those obtained in deeper anterior chambers.

A prediction model for sulcus-to-sulcus diameter in myopic eyes: a 1466-sample retrospective study

Background

To establish and verify the accuracy and reliability of a sulcus-to-sulcus diameter (STS) prediction model.

Methods

In this retrospective study, the prediction formula was established with the data from 1466 eyes from 733 subjects from July 2020 to April 2021 and verified with the data from 278 eyes from 139 subjects between May 2021 and June 2021. Each subject was measured with a Pentacam, IOLMaster 700, OPD-Scan III, and ultrasound biomicroscope. The prediction formulas were established with multiple linear regression, and intergroup correlation coefficients (ICCs) and Bland–Altman tests were used to assess the agreement between the predicted and actual STS (actual STS was measured by UBM).

Results

The explanatory variables relevant to the horizontal STS (STSH) were the Pentacam white-to-white diameter (WTWP; standardized partial regression coefficient [β] = 0.330; p < 0.001), the flat K value (β = -0.211; p < 0.001), and the anterior corneal diameter (ACD) (β = 0.178; p < 0.001). The corresponding multiple regression equation was : STSH (mm) = 8.061 + 0.510 × WTWP − 0.090 × Flat K value + 0.430 × ACD. The explanatory variables relevant to the vertical STS (STSV) were the WTWP (β = 0.435; p < 0.001), the steep K value (β = -0.271; p < 0.001), and the ACD (β = 0.187; p < 0.001). The corresponding multiple regression equation was : STSV (mm) = 8.540 + 0.492 × WTWP − 0.075 × Steep K value + 0.329 × ACD. The bias of the predicted to the actual STSH was − 0.021, with 95% limits of agreement (95% LoA) from − 0.499 to 0.457. The bias of the predicted to the actual STSV was 0.057, with 95% LoA from − 0.462 to 0.575. The ICC was 0.883 between the predicted and actual STSH and 0.859 between the predicted and actual STSV.

Conclusions

The Pentacam-measured WTW, the K value and the ACD are important for predicting the STS diameter. The prediction model has good accuracy and reliability.

Trial registration

Not applicable.

Smartphone-Acquired Anterior Segment Images for Deep Learning Prediction of Anterior Chamber Depth: A Proof-of-Concept Study

Purpose

To develop a deep learning (DL) algorithm for predicting anterior chamber depth (ACD) from smartphone-acquired anterior segment photographs.

Methods

For algorithm development, we included 4,157 eyes from 2,084 Chinese primary school students (aged 11–15 years) from Mojiang Myopia Progression Study (MMPS). All participants had with ACD measurement measured with Lenstar (LS 900) and anterior segment photographs acquired from a smartphone (iPhone Xs), which was mounted on slit lamp and under diffuses lighting. The anterior segment photographs were randomly selected by person into training (80%, no. of eyes = 3,326) and testing (20%, no. of eyes = 831) dataset. We excluded participants with intraocular surgery history or pronounced corneal haze. A convolutional neural network was developed to predict ACD based on these anterior segment photographs. To determine the accuracy of our algorithm, we measured the mean absolute error (MAE) and coefficient of determination (R²) were evaluated. Bland Altman plot was used to illustrate the agreement between DL-predicted and measured ACD values.

Results

In the test set of 831 eyes, the mean measured ACD was 3.06 ± 0.25 mm, and the mean DL-predicted ACD was 3.10 ± 0.20 mm. The MAE was 0.16 ± 0.13 mm, and R² was 0.40 between the predicted and measured ACD. The overall mean difference was −0.04 ± 0.20 mm, with 95% limits of agreement ranging between −0.43 and 0.34 mm. The generated saliency maps showed that the algorithm mainly utilized central corneal region (i.e., the site where ACD is clinically measured typically) in making its prediction, providing further plausibility to the algorithm's prediction.

Conclusions

We developed a DL algorithm to estimate ACD based on smartphone-acquired anterior segment photographs. Upon further validation, our algorithm may be further refined for use as a ACD screening tool in rural localities where means of assessing ocular biometry is not readily available. This is particularly important in China where the risk of primary angle closure disease is high and often undetected.

Comparison of Vault Measurements Using a Swept-Source OCT-Based Optical Biometer and Anterior Segment OCT

Background

To newly describe the vault measurement by using a widely used swept-source OCT-based optical biometer (IOLMaster700) and accessd the accuracy of vault measurement.

Methods

This was a retrospective, cross-sectional study. All patients underwent implantable Collamer lens (ICL) implantation surgery without complications. IOLMaster700 and AS-OCT analyses were conducted for each eye on the same day in the same condition. Measurements of anterior chamber depth (ACD), corneal-ICL (C-ICL), and vault values were made and recorded. The repeatability of the IOL Master700 measurements was quantified based upon intraclass correlation coefficient (ICC) values. Correlations between IOL Master700 and AS-OCT measurements made with these different analytical approaches were assessed. The agreement of instruments was evaluated using Bland-Altman plots.

Results

The IOLMaster700 instrument yielded highly reliable measurements of vault, C-ICL, and ACD (ICC = 0.996, 0.995, 0.995, respectively). Vault, C-ICL and ACD values as measured using the IOLMaster700, was slightly smaller than that measured via AS-OCT, but these differences were not significant (p = 0.652, p = 0.121 and p = 0.091, respectively). The vault, C-ICL, and ACD measurements by these two instruments were strongly correlated (r = 0.971, r = 0.944, and r = 0.963, respectively; all p &lt; 0.001). The 95% limits of agreement for vault, C-ICL, and ACD measurements between the two devices were−0.08 to 0.08 mm,−0.14 to 0.11 mm, and−0.13 to 0.10 mm, respectively.

Conclusions

The IOLMasrer700 can measure implanted ICL vault with a high degree of accuracy and repeatability. Good correlations and agreement were observed between IOLMaster700 and AS-OCT in measuring vault, C-ICL, and ACD measurements.

First Experiences with Implantation of Phakic Lenses in Correction of Myopia in R. N. Macedonia

Objective: Analysis of visual acuity parameters in patients with moderate to high myopia and myopic astigmatism 1 year after treatment with phakic intraocular lenses. Material and methods: This was a retrospective study on 35 patients (52 eyes) with moderate to high myopia who were implanted with the Visian V4c phakic implantable Collamer lens (Staar Surgical, Nidau, Switzerland). Examined parameters were: uncorrected distance visual acuity (UDVA) and best corrected visual acuity (CDVA), manifest and cycloplegic refraction, intraocular pressure, and endothelial cell count. The investigated parameters were measured preoperatively, 1, 3, 6 and 12 months postoperatively. Results: In 17 patients, phakic lenses were implanted binocularly and in 18 patients monocularly. Preoperatively 34.62% of patients had CDVA from 0.9 to 1.0. One year after the surgery 48.08% of patients had UDVA from 0.9 to 1.0. Preoperatively 80.77% of patients had diopter range from -6.00 Dsph to -10.00 Dsph. At 1 year postoperatively 78.85% of patients were within 0.00 Dsph to -1.00 Dsph. Preoperatively, in patients with astigmatism -4 Dcyl to -2 Dcyl dominated, as opposed to significant improvement postoperatively when 94.23% had astigmatism ranging from -1.0 Dcyl to 0 Dcyl. Conclusion: The implantation of phakic lenses demonstrated a successful postoperative outcome in the treatment of myopia and myopic astigmatism. Visual acuity and refraction show a gradual and significant improvement in visual function parameters within 1 year of lens implantation.

Distribution of White-to-White Corneal Diameter and Anterior Chamber Depth in Chinese Myopic Patients

Purpose: To investigate the distribution of white-to-white (WTW) corneal diameter and anterior chamber depth (ACD) in Chinese myopia patients. Methods: This was a cross-sectional observational study conducted at five ophthalmic centers. Anterior segment biometry was performed in 7,893 eyes of the 7,893 myopic patients using Pentacam, and the WTW and ACD were recorded. The distribution patterns of WTW and ACD were evaluated and the correlation between WTW and ACD was analyzed statistically. Results: There were 4416 (55.95%) males and 3477 (44.05%) females. The age of the study population was 25.14 ± 5.41 years. Distribution of WTW was slightly positively skewed (Skewness = 0.0076, Kurtosis = 0.3944, KS P = 0.020) with a mean of 11.65 ± 0.38 mm and a 95% normal range of 10.91-12.39 mm. A significant difference in WTW was found among different myopia groups (P < 0.001). The ACD was normally distributed (Skewness = 0.899, Kurtosis = 0.027, KS P = 0.086). The mean ACD was 3.25 ± 0.26 mm and the 95% normal range of was 2.74-3.75 mm. A significant difference in ACD was also found among different myopia groups (P = 0.030). There was a significant correlation between WTW and ACD (r = 0.460, P < 0.001). Conclusions: In our study, 95% of the Chinese myopic patients had a WTW within 10.91-12.39 mm and an ACD within 2.74-3.75 mm. ACD and WTW were significantly different among different myopia, gender and age groups. WTW was positively correlated with ACD.

Visual Outcomes, Footplate Position and Vault Achieved with the Visian Implantable Collamer Lens for Myopic Astigmatism

Purpose

Report the outcomes of the implantable collamer lens (ICL) in myopic astigmatism using very high-frequency (VHF) digital ultrasound sizing.

Methods

Analysis of 42 consecutive ICL procedures using EVO and EVO+ (Visian V4c) lenses (STAAR Surgical) was done. ICL size was chosen using the ultrasound-based Kojima Formula with Insight 100 VHF digital ultrasound (VHFDU). Standard visual outcomes analysis was performed using 3-month data, also including contrast sensitivity, refractive and corneal vector analysis, and ECC. Postoperative lens position was evaluated using VHF digital ultrasound.

Results

Attempted SEQ was −10.83±3.39D (−4.40 to −16.98D). Cylinder was −1.46±1.15D (0.00 to −4.25D). One-year follow-up was available in 86% of the eyes and 3 months in 96%. Postoperative UDVA was 20/20 or better in 89% of the eyes, relative to 71% preoperatively. Postoperative SEQ refraction was ±0.50 D in 74% and ±1.00 D in 98% of the eyes. There was a gain of one line of CDVA in 43% of the eyes, 2 or more lines in 10% of the eyes, while there was a one line loss in 7% and no eyes lost 2 or more lines. The vector mean for the corneal SIA was 0.24 D Ax 100. Contrast sensitivity showed a statistically significant increase with a mean of 0.14 log units at 6, 12, and 18 cycles per degree (P<0.01). The mean change in ECC was −153±353 cells/mm². Lens vault was 506±233 µm (114–924 µm). Footplate insertion was in zonular position in 48.3%, ciliary body in 49.2%, and sulcus in 2.5% of locations.

Conclusion

ICL implantation resulted in high safety and efficacy but with an implantation vault range that ideally would be improved upon. VHF digital ultrasound of the lens footplate and posterior anatomical relations may provide essential information for evaluating postoperative vault outliers.

Consecutive contralateral comparison of toric and non-toric implantable collamer lenses V4c in vault after implantation for myopia and astigmatism

AIMS

To compare the vault performance between implantable collamer lens (ICL) V4c and Toric ICL (TICL) V4c after implantation and to investigate the affecting factors.

METHODS

Sixty-eight eyes from 34 patients with myopia or myopia astigmatism who underwent implantation of TICL in one eye (group A) and identically sized ICL (group B) in the contralateral eye were included. Mean follow-up time were 7.58 ± 1.63 months (range: 6-10 months). Vault was compared between the two groups and correlations between vault and age, preoperative ocular biometric measurements were analysed. Generalized estimating equation (GEE) model of postoperative vault adjusting for within-patient intereye correlations was performed.

RESULTS

The safety indices were 1.27 and 1.35, and the efficacy indices were 1.20 and 1.24 for groups A and B, respectively. Vault of TICL was significantly higher than that of ICL (554.11 ± 219.36 μm vs 449.70 ± 172.47 μm, P < 0.001). The difference between ICL/TICL size and WTW (size-WTW) and STS (size-STS), anterior chamber depth and pupil diameter (PD) were positively correlated with vault. Patient age and clear lens rise measured by Pentacam were negatively correlated with vault. Results of GEE model showed preoperative PD, age, cylindrical power of TICL and size-WTW were influencing factors for postoperative vault.

CONCLUSIONS

Vault after TICL implantation is higher than that with ICL. PD, age, cylindrical power of TICL and size-WTW could affect postoperative vault.

Development of a Web-Based Ensemble Machine Learning Application to Select the Optimal Size of Posterior Chamber Phakic Intraocular Lens

Purpose

Selecting the optimal lens size by predicting the postoperative vault can reduce complications after implantation of an implantable collamer lens with a central-hole (ICL with KS-aquaport). We built a web-based machine learning application that incorporated clinical measurements to predict the postoperative ICL vault and select the optimal ICL size.

Methods

We applied the stacking ensemble technique based on eXtreme Gradient Boosting (XGBoost) and a light gradient boosting machine to pre-operative ocular data from two eye centers to predict the postoperative vault. We assigned the Korean patient data to a training (N = 2756 eyes) and internal validation (N = 693 eyes) datasets (prospective validation). Japanese patient data (N = 290 eyes) were used as an independent external dataset from different centers to validate the model.

Results

We developed an ensemble model that showed statistically better performance with a lower mean absolute error for ICL vault prediction (106.88 µm and 143.69 µm in the internal and external validation, respectively) than the other machine learning techniques and the classic ICL sizing methods did when applied to both validation datasets. Considering the lens size selection accuracy, our proposed method showed the best performance for both reference datasets (75.9% and 67.4% in the internal and external validation, respectively).

Conclusions

Applying the ensemble approach to a large dataset of patients who underwent ICL implantation resulted in a more accurate prediction of vault size and selection of the optimal ICL size.

Translational Relevance

We developed a web-based application for ICL sizing to facilitate the use of machine learning calculators for clinicians.

Optical and visual quality comparison of implantable collamer lens and femtosecond laser assisted laser in situ keratomileusis for high myopia correction

AIM

To compare clinical outcomes and refractive stability of implantable collamer lens (ICL) implantation and femtosecond laser assisted laser in situ keratomileusis (FS-LASIK) for high myopia correction.

METHODS

The Optical Quality Analysis System (OQAS) was used to evaluate clinical outcomes objectively after operation for high myopia correction. We compared the two procedures in terms of 1-year changes in uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), safety index, efficacy index, spherical equivalent, modulation transfer function (MTF) cutoff frequency, strehl ratio (SR) and objective scatter index (OSI).

RESULTS

At 1y postoperatively, the safety indices were 1.33±0.27 in ICL group, and 1.17±0.24 in FS-LASIK group. 39.58% in the ICL group and 27.59% in the FS-LASIK group gained CDVA in 2 lines or better than that in preoperative CDVA. The efficacy indices were 1.28±0.22 in ICL group, and 1.13±0.26 in FS-LASIK group. The changes of spherical equivalent from 1wk to 1y postoperatively was -0.12±0.37 D in ICL group, and -0.79±0.58 D in FS-LASIK group (P<0.05). Spherical equivalent within ±0.50 D was achieved in 97.92% in ICL group and 68.97% in FS-LASIK group. MTF cutoff frequency were higher with ICL as compared to FS-LASIK (P<0.05) at each postoperative follow-up stage; for postoperative 1mo later, SR was statistically significant difference between two groups (P<0.05); with no statistically significant difference in OSI between two groups (P>0.05) in postoperative 3mo later.

CONCLUSION

ICL implantation and FS-LASIK procedures both provide good safety and predictability in high myopia correction. ICL implantation provides better clinical outcomes and refractive stability than FS-LASIK.

Short-term changes in and preoperative factors affecting vaulting after posterior chamber phakic Implantable Collamer Lens implantation

Background

To describe the very early vault changes in the first month after Implantable Collamer Lens (ICL) implantation and to evaluate the effect of preoperative biometric factors on vault.

Methods

Eighty-three eyes from eighty-three subjects with complete data who met follow-up requirements were recruited in this retrospective study between May 2019 and March 2020. We quantitatively assessed the postoperative vault at 2 h, 1 day, 1 week, and 1 month following implantation. Associations between the postoperative vault and age, ICL size, spherical equivalent (SE), axial length (AL), central corneal thickness (CCT), flat keratometry (K), steep K, mean K, anterior chamber depth (ACD), crystalline lens thickness (LT), white-to-white (WTW) diameter obtained by three devices, horizontal and vertical sulcus-to-sulcus (STS) diameter, bright and dark pupil sizes (BPS and DPS) and DPS-BPS were investigated using Spearman’s correlation analysis and stepwise multiple regression analysis.

Results

The mean vault values at 2 h, 1 day, 1 week, and 1 month after ICL implantation were 672.05 ± 30.72, 389.15 ± 28.33, 517.23 ± 30.76 and 530.12 ± 30.22 μm, respectively. Significant differences were found in the vault values at 2 h, 1 day and 1 week after the operation. The ICL size (β = 0.942; p < 0.001), followed by horizontal STS (β = -0.517; p < 0.001), crystalline LT (β = -0.376; p < 0.001) and vertical STS (β = -0.257; p = 0.017), significantly influenced the vault at 1 month after the operation. The multiple regression equation was expressed as follows: central vault (µm) = -1369.05 + 657.121 × ICL size- 287.408 × horizontal STS − 432.497 × crystalline LT − 137.33 × vertical STS (adjusted R² = 0.643).

Conclusions

After ICL implantation, the vault decreased and then increased, but it did not return to the vault value 2 h after surgery. The ICL size, horizontal and vertical STS and crystalline LT are key factors for predicting postoperative vaulting.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12886-021-01963-x.

Posterior-chamber phakic implantable collamer lenses with a central port: a review

We aimed to summarize the outcomes reported following the implantation of the V4c implantable collamer lens with a central port (ICL, STAAR Surgical Inc) for myopia correction. A literature search in PubMed, Web of Science and Scopus was carried out to identify publications reporting clinical outcomes of patients who were implanted with the V4c ICL model and had a follow‐up period of at least 6 months. A total of 35 clinical studies published between 2012 and 2020 were included in the present review. A comprehensive analysis of the available data was performed, focusing on visual and refractive outcomes at different time‐points post‐surgery. In addition, adverse events and other parameters such as endothelial cell density, intraocular pressure and vault measurements—which were evaluated in some of the studies—were also compared. This review encompassed a total of 2904 eyes. The outcomes reported in this review lead us to conclude that ICL V4c implantation for myopia correction is a safe and efficient procedure, with stable visual and refractive outcomes and low adverse event rates. The patient’s anterior segment should be thoroughly characterized, and the ICL parameters should be carefully selected so as to achieve good outcomes and avoid complications.

Long-Term Outcomes of Retinal Detachment in Phakic Eyes After Implantation of Implantable Collamer Lens V4c for High Myopia Correction

Aim: To estimate whether implantable collamer lens (V4c ICL) implantation increases the risk of retinal detachment in high myopia comparing with myopes with Rigid Gas-Permeable (RGP) correction.

Methods: This prospective study was comprised of an ICL group (704 eyes) and an RGP group (628 eyes). Patients were enrolled according to the inclusion criteria and exclusion criteria, then divided into the ICL group and RGP group. Patients in the ICL and RGP groups received V4c ICL implantation and RGP fitting respectively. Retinal details, spherical equivalent refraction (SE), uncorrected distance visual acuity (UDVA), corrected distance vision acutivity (CDVA), axis length (AL), anterior chamber depth (ACD) and other relevant parameters were recorded at different time points. Rhegmatogenous retinal detachment (RRD) morbidity and incidence, RRD morphology and relevant parameters were analyzed.

Results: All enrolled patients were followed for 3–6 years. Patients characteristics before the refractive procedure did not show a statistical difference. At the end of the follow up, all the RD cases were RRD. The RRD morbidity of the ICL group and RGP group was 1.99% (14 eyes) and 0.96% (6 eyes) respectively, which did not show statistical difference (P = 0.12). During the first year after refractive procedure, the RRD incidence of the ICL group was 0.85% (6/704), while this number of the RGP group was 0.16% (1/628). It did not show statistical difference (P = 0.08).

Conclusion: Compared with RGP fitting, V4c ICL implantation for high myopia correction does not add RRD risk in the long term. V4c ICL implantation is a safe method for high myopia correction.

Phakic intraocular lenses: An overview

Phakic intraocular lenses (pIOLs) are a common solution for the surgical correction of high myopia and myopia in thin corneas. Global trends result in increasing rates of patients with high myopia which will result in increased rates of pIOL implantation. Three types of lenses can be distinguished: anterior chamber angle-supported, anterior chamber iris-fixated, and posterior chamber phakic IOLs. The efficacy of phakic intraocular lenses is generally very good, but pIOLs have undergone many changes over the years to improve the safety profile and decrease pIOL-related complications such as endothelial cell loss, corneal decompensation and cataract formation. This article describes the efficacy and safety profiles of the most recent pIOLs, as well as suggests gaps of knowledge that are deserve additional research to optimize the results of pIOLs.

One-year visual outcomes and optical quality of femtosecond laser small incision lenticule extraction and Visian Implantable Collamer Lens (ICL V4c) implantation for high myopia

PURPOSE

To compare one-year visual outcomes and optical quality after femtosecond laser small incision lenticule extraction (SMILE) and Visian Implantable Collamer Lens with a central hole (ICL V4c) implantation for high myopia.

METHODS

This prospective non-randomized study included 37 eyes of 20 patients who underwent SMILE (G-S) and 39 eyes of 20 patients who underwent ICL V4c implantation (G-V). Spherical equivalent (SE), uncorrected distance visual acuity, corrected distance visual acuity, retinal image quality and intraocular scattering were evaluated at one year after surgery. Each model was adjusted for age, gender, eye and preoperative SE during treatment.

RESULTS

At the one-year follow-up, G-S and G-V showed similar safety index (1.13 ± 0.13 and 1.11 ± 0.15, respectively) and efficacy index (1.05 ± 0.14 and 1.06 ± 0.15, respectively). All 21 eyes with Toric ICL (TICL) had a postoperative astigmatism of ≤0.5 dioptres (D), while the astigmatism was ≤0.5 D in all G-S eyes. Thirty-six G-S eyes (97%) and 35 G-V eyes (90%) were within ± 0.5 D of the target SE. The changes in the modulation transfer function cut-off frequency (MTF_cut-off ) and the objective scatter index from before operation to one year following the operation were not significantly different between the groups (p = 0.523 and 0.826, respectively).

CONCLUSION

Both SMILE and ICL V4c implantation provide good safety, efficacy, predictability, and stability in correcting high myopia. Optical quality including intraocular scattering was great and relatively stable in both groups during the one-year observation period.

Posterior-Chamber Phakic Intraocular Lens Implantation in Patients over 40 Years of Age

Purpose

To assess the efficacy, safety, and predictability of the Visian Implantable Collamer Lens (ICL) model having a central port in patients over 40 years of age.

Methods

This study included 33 eyes from 21 patients who underwent V4c ICL implantation for the correction of myopia and myopic astigmatism. We assessed uncorrected (UDVA) and corrected (CDVA) distance visual acuity, refraction, intraocular pressure (IOP), endothelial cell density (ECD), vault, and adverse events occurring over a 1-year period.

Results

Mean age of the patients at the time of implantation was 43.52 ± 4.49 years (range: 40 to 56 years). Efficacy and safety indexes were 1 and 1.09, respectively. Surgical outcomes for CDVA were as follows: no eye lost any lines, 19 eyes (57.58%) showed no CDVA changes, 7 eyes (21.21%) gained 1 line, 4 eyes (12.12%) gained 2 lines, and 3 eyes (9.09%) gained ≥3 lines. Mean postoperative spherical equivalent (SE) was −0.09 ± 0.47 D. A total of 29 eyes (87.8%) were within ±0.50 D and 31 eyes (93.9%) were within ±1.00 D of the desired SE. At 1-year, mean IOP was 15.27 ± 3.03 mmHg (range: 9 to 20 mmHg, p=0.12 pre vs. post) and mean ECD was 2516 ± 234 cells/mm² (p=0.29 pre vs. post). Mean postoperative vault was 320 ± 136 μm, with 201–300 μm being the most prevalent vault range for 9 eyes (31.03%). None of the eyes showed a vault >701 μm. There were neither intraoperative nor postoperative complications; in fact, all ICL implantation procedures were uneventful.

Conclusions

Our study's findings support the use of this lens in patients over 40 years of age. A long follow-up period is advisable to monitor ICL position relative to the crystalline lens.

Four-year observation of the changes in corneal endothelium cell density and correlated factors after Implantable Collamer Lens V4c implantation

Background

To evaluate the changes in corneal endothelium cell density (ECD) and the correlated factors after Implantable Collamer Lens (ICL) V4c implantation.

Methods

In this retrospective, consecutive study, 48 eyes of 25 patients with myopia who underwent ICL V4c implantation were enrolled. Patients were followed up for at least 4 years, during which manifest refraction, uncorrected distance visual acuity, corrected distance visual acuity (CDVA), intraocular pressure, ECD, anterior chamber depth, anterior chamber volume (ACV), anterior chamber angle (ACA), vault and distance from the corneal endothelium to the central ICL (C-ICL) were measured. Spearman’s correlation analysis was used to identify variables correlated with changes in ECD, and generalised estimating equation model adjusting within-patient intereye correlations was used to predict changes in ECD.

Results

All surgeries were performed safely with no complications during follow-up (average 52±2.9 months). Safety and efficacy indices were 1.23±0.22 and 1.04±0.16, respectively. No eyes had decreased CDVA, and 67% gained one or more lines. Further, 79% were within ±0.50 D, and 100% were within ±1.0 D of the attempted refraction. Additionally, a 4.03%±2.2% reduction in ECD compared with the preoperative value was observed at the last follow-up visit. Changes in ECD were significantly correlated with vault, C-ICL, change in ACA and change in ACV. Vault was the most significant factor for changes in ECD.

Conclusions

ICL V4c implantation is safe and effective for myopia correction. Anterior segment biometric parameters including the vault, ACA and C-ICL may influence changes in ECD; specifically, the vault plays a major role.

Evaluation of Disk Halo Size after Implantation of a Collamer Lens with a Central Hole (ICL V4c)

Purpose

To investigate disk halo size changes produced by a glare source after surgical insertion of an implantable collamer lens with a central hole (ICL V4c) for myopia correction.

Methods

In this prospective study, disk halo size and pupillary light response with a vision monitor were measured preoperatively and at 1 week, 1 month, and 3 months postoperatively. Pupillary light response parameters included contraction amplitude, latency, duration, and velocity; dilation latency, duration, and velocity; and initial, maximum, minimum, and average pupil diameters.

Results

Forty-two right eyes of 42 patients were enrolled. Postoperative uncorrected distance visual acuity was better than or equal to 20/20 in all eyes. Compared to preoperative values, disk halo size showed no significant difference at 1 week postoperatively (P > 0.05) and then decreased significantly at 1 and 3 months postoperatively (both P < 0.001). Contraction amplitude and velocity, as well as dilation velocity, decreased significantly at all postoperative time points (all P < 0.001). Disk halo size at 3 months postoperatively was significantly correlated with initial (r = 0.446, P=0.003), maximum (r = 0.483, P=0.001), minimum (r = 0.425, P=0.005), and average pupil diameters (r = 0.474, P=0.002).

Conclusions

After ICL V4c implantation, disk halo size was reduced in the short term. Patients with smaller pupil sizes during pupillary response to light experienced smaller halos after ICL V4c implantation.