SMILE Versus Implantable Collamer Lens Implantation for High Myopia: A Matched Comparative Study

Epithelial Remodeling and Epithelial Wavefront Aberrometry after Spherical vs. Cylindrical Myopic Small Incision Lenticule Extraction (SMILE)

Background/Objectives: To compare the epithelial thickness changes and the changes in epithelial wavefront aberrometry following spherical versus astigmatic myopic small incision lenticule extraction (SMILE). Methods: Eighty-six eyes of 86 patients who underwent SMILE were included in this retrospective study. A total of 43 eyes underwent myopic spherical correction (spherical group) and 43 eyes underwent myopic cylindrical correction (cylindrical group). The groups were matched according to the spherical equivalent of surgically corrected refraction. Subjective manifest refraction as well as high-resolution anterior segment optical coherence tomography (MS-39; CSO; Florence, Italy) were obtained preoperatively as well as 3 months postoperatively. The latter was utilized for computing epithelial wavefront aberrometry in addition to epithelial thickness mapping. Results: Epithelial thickness increased significantly in both groups after SMILE (p < 0.01). In the cylindrical group, epithelial thickening was more pronounced on the flat meridian compared to the steep meridian (p = 0.04). In both groups, epithelial wavefront aberrometry showed a significant postoperative increase in the epithelium's spherical refractive power, causing a myopization of -0.24 ± 0.42 diopters (D) in the spherical group (p < 0.01) and -0.41 ± 0.52 D in the cylindrical group (p < 0.0001). While no significant changes in epithelial cylindrical refractive power were observed in the spherical group, a significant increase was noted in the cylindrical group from -0.21 ± 0.24 D to -0.37 ± 0.31 D (p = 0.01). In both groups, epithelial higher-order aberrations increased significantly (p < 0.001). Conclusions: Postoperative epithelial remodeling after SMILE alters lower-order (sphere and cylinder) and higher-order aberrations of the corneal epithelial wavefront and might contribute to refractive undercorrection, especially in astigmatic corrections. Epithelial wavefront aberrometry can be used to quantify the refractive effect of epithelial remodeling processes after keratorefractive surgery.

Meridional analysis for calculation of the toric power of phakic IOLs

PURPOSE

To present a reproducible method to calculate the toricity needed at the intraocular lens (IOL) plane with toric phakic IOLs (ICL, Staar Surgical) and compare its results with those obtained with the online calculator provided by the manufacturer.

DESIGN

Retrospective case series.

SETTING

Private practice, Buenos Aires, Argentina.

METHODS

The formula originally described by Holladay to calculate the IOL power in phakic eyes was used to calculate the required spherical power along the less refractive meridian and along the more refractive meridian. Meridional analysis was applied to calculate the required toricity at the IOL plane and the surgically induced corneal astigmatism was incorporated into the calculations. The refractive cylinder predicted by this method and by the online calculator of the manufacturer were compared to the postoperative refractive cylinder by means of vector analysis. The possible changes in the ratio of toricity in patients with different amounts of astigmatism and anterior chamber depth are assessed in a theoretical section.

RESULTS

In 35 eyes, the measured mean postoperative refractive cylinder was 0.09 D @ 99°, the mean predicted postoperative refractive astigmatism was 0.04 D @ 102° according to the manufacturer's online calculator and 0.09 D @100° according to our method. With both methods, 91.43% of eyes had an absolute cylinder prediction error within ±0.50 diopters.

CONCLUSIONS

The method described in this article to calculate the toricity of phakic IOLs has a refractive accuracy similar to that of the original calculator developed by the manufacturer.

Comparative Analysis of Visual Outcomes and Complications in Intraocular Collamer Lens, Small-Incision Lenticule Extraction, and Laser-Assisted In Situ Keratomileusis Surgeries: A Comprehensive Review

This review provides a comparative analysis of visual outcomes and complications associated with three prominent refractive surgical techniques: intraocular collamer lens (ICL) implantation, small-incision lenticule extraction (SMILE), and laser-assisted in situ keratomileusis (LASIK). Refractive surgeries aim to correct myopia, hyperopia, and astigmatism, offering patients an alternative to corrective lenses. The review highlights the importance of comparing these procedures to guide clinical decision-making effectively. Each technique is described, emphasizing its unique advantages and considerations. While LASIK remains widely favored for its rapid visual recovery and high patient satisfaction, ICL is suitable for patients with higher refractive errors or corneal irregularities. Although relatively newer, SMILE shows promise with potential benefits such as corneal biomechanical stability and a reduced risk of dry eye syndrome. However, each procedure carries its distinct complications, reinforcing the need for personalized patient care and informed decision-making. Understanding these techniques' relative efficacy and safety profiles is essential for optimizing outcomes and enhancing patient satisfaction. Continued advancements in technology and surgical techniques promise further improvements in refractive surgery outcomes, underscoring the importance of ongoing research and innovation.

The rate of vault changes after ICL V4c implantation and its correlation with anterior segment parameters

Purpose

To investigate the rate of vault changes after implantation of ICL V4c and the correlation with anterior segment parameters.

Methods

A total of 64 eyes were studied from the 37 myopic subjects recruited. CASIA2 was used to record the vault at 1 week, 1 month, 3 months and 6 months after the operation as well as the preoperative anterior segment parameters including pupil diameter, lens vault, anterior chamber depth, anterior chamber width, iris area (IA), iris thickness, angle opening distance, angle recess area, trabecular iris space area, and trabecular iris angle. The rates of vault change in different time intervals were compared and the correlations between the rates and anterior segment parameters were analyzed. P < 0.05 was considered statistically significant.

Results

The rate of vault decrease was -19.53 ± 111.28 μm/month between 1 week and 1 month, -19.90 ± 29.71 μm/month between 1 month and 3 months and -4.25 ± 18.10 μm/month between 3 months and 6 months; hence the rate was shown to slow down significantly from 3 months post-operation (P = 0.024). The average rate of vault changes showed a significant positive correlation with IA (R2 = 0.140, F = 4.980, P = 0.01). No significant correlation was found with other anterior segment parameters (all P > 0.05).

Conclusion

The rate of decreasing vault significantly slowed down from 3 months post-operation. A larger IA may imply a lower decreasing rate of vault change.

Four-year visual outcomes and optical quality of SMILE and implantable collamer lens V4c (EVO-ICL) implantation for high myopia: a retrospective study

BACKGROUND

To compare the 4-year visual outcomes of implantable collamer lens V4c (EVO-ICL) implantation and small incision lenticule extraction (SMILE) for high myopia and astigmatism.

METHODS

This retrospective case study included 64 eyes of 40 patients. These patients with preoperative manifest refraction spherical equivalent (SE) between - 6.00 and - 10.00 diopters (D) were screened from the database of SMILE and EVO-ICL implantation procedures in 2015. The ICL group [32 eyes of 19 patients (mean age, 29.6 ± 6.3 years); mean SE, -8.71 ± 1.06 D] and SMILE group [32 eyes of 21 patients (mean age, 27.7 ± 5.6 years); mean SE, -8.35 ± 0.65D] were compared. All patients were then prospectively examined at a four-year follow-up for routine postoperative examinations, higher-order ocular aberrations, retinal image quality and a questionnaire.

RESULTS

The safety indexes were 1.15 ± 0.14 and 1.22 ± 0.21 (P = 0.36) for the SMILE and ICL groups, respectively. No eyes lost two or more lines of CDVA in either group. The efficacy indexes were 0.97 ± 0.16 and 0.96 ± 0.19 (P = 0.87), respectively. Twenty-three eyes (72%) in ICL and 26 eyes (81%) in SMILE groups were within ± 0.5 D of the attempted SE (P < 0.01). ICL-treated eyes had significantly less spherical aberration and coma (P < 0.01 and < 0.05, respectively) postoperatively. Halos were the prevalent visual disturbance in both groups.

CONCLUSION

SMILE and EVO-ICL implantation provided safe and effective correction of high myopia. SMILE showed slightly better long-term predictability. Mild postoperative visual disturbances were observed after ICL and SMILE at 4-year follow-up.

TFOS Lifestyle: Impact of elective medications and procedures on the ocular surface

The word "elective" refers to medications and procedures undertaken by choice or with a lower grade of prioritization. Patients usually use elective medications or undergo elective procedures to treat pathologic conditions or for cosmetic enhancement, impacting their lifestyle positively and, thus, improving their quality of life. However, those interventions can affect the homeostasis of the tear film and ocular surface. Consequently, they generate signs and symptoms that could impair the patient's quality of life. This report describes the impact of elective topical and systemic medications and procedures on the ocular surface and the underlying mechanisms. Moreover, elective procedures performed for ocular diseases, cosmetic enhancement, and non-ophthalmic interventions, such as radiotherapy and bariatric surgery, are discussed. The report also evaluates significant anatomical and biological consequences of non-urgent interventions to the ocular surface, such as neuropathic and neurotrophic keratopathies. Besides that, it provides an overview of the prophylaxis and management of pathological conditions resulting from the studied interventions and suggests areas for future research. The report also contains a systematic review investigating the quality of life among people who have undergone small incision lenticule extraction (SMILE). Overall, SMILE refractive surgery seems to cause more vision disturbances than LASIK in the first month post-surgery, but less dry eye symptoms in long-term follow up.

Comparison of higher-order aberrations between implantable collamer lens V4c implantation and simulated spectacle correction in patients with high myopia

PURPOSE

To investigate the differences in higher-order aberrations between non-toric or toric implantable collamer lens (ICL or TICL) V4c implantation and simulated spectacle correction.

METHODS

Patients with high myopia who underwent ICL/TICL V4c implantation were enrolled. The "total no defocus" pattern of iTrace aberrometry to simulate the condition of spectacle correction was measured before ICL/TICL implantation, and higher-order aberrations in this condition were compared to those 3 months after surgery. Related factors with changes in coma were comprehensively analyzed.

RESULTS

A total of 89 right eyes of 89 patients were included. Compared to simulated spectacle correction, total-eye coma (P<0.0001 ICL, P<0.0001 TICL) and internal coma (P<0.0001 ICL, P<0.001 TICL) decreased in the ICL- and TICL-treated groups after surgery. Total-eye secondary astigmatism (P<0.0001 ICL, P=0.007 TICL) and internal secondary astigmatism (P<0.0001 ICL, P=0.009 TICL) were also decreased in both groups postoperatively. Spherical error showed positive correlations with variation in total-eye coma (r=0.37, P=0.004 ICL; r=0.56, P=0.001 TICL) and internal coma (r=0.30, P=0.02 ICL and r=0.45, P=0.01 TICL). Axial length revealed negative correlations with changes in total-eye coma (r=-0.45, P<0.001 ICL; r=-0.39, P=0.03 TICL) and internal coma (r=-0.28, P=0.03 ICL and r=-0.42, P=0.02 TICL).

CONCLUSIONS

Both ICL- and TICL-treated groups demonstrated a decrease in coma and secondary astigmatism after 3 months, postoperatively. ICL/TICL may confer a compensatory effect on coma aberration and secondary astigmatism. Patients with a higher myopia achieved a greater improvement in coma and may benefit more from ICL/TICL implantation than from spectacle correction implantation than from spectacle correction.

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

BACKGROUND

To evaluate anterior segment structural alterations after implantable collamer lens (ICL) implantation in myopic patients using swept-source quantitative optical coherence tomography (SS-OCT).

METHODS

This prospective study included 47 eyes in 24 patients with preoperative spherical equivalent ≥ -3.00 D. Patients underwent ICL implantation at Department of Ophthalmology, Peking University Third Hospital, from May 2021 to December 2022. SS-OCT was used to measure anterior chamber width (ACW), angle opening distance (AOD), angle recess area (ARA), trabecular-iris area (TISA), trabecular-iris angle (TIA), iridotrabecular contact (ITC) area, and ITC Index before ICL implantation surgery and at 1 month follow-up. The correlations among the ITC index, vault, and angle parameters were analysed. Receiver operating characteristic (ROC) analysis was used to explore the ability of the vault to identify eyes with suspected angle-closure.

RESULTS

At one month following ICL implantation, the ITC area was 0.396 ± 0.37 mm², and the ITC index is 8.143 ± 5.439%. All angle parameters, except ACW, showed a statistically significant reduction on SS-OCT (P < 0.05). Mean AOD500, AOD750, ARA500, ARA750, TISA500, TISA750, TIA500, and TIA750 values at one month postoperatively decreased by 60.0%, 60.4%, 58.1%, 59.2%, 57.3%, 58.7%, 48.8%, and 50.7%, respectively. The vault was positively correlated with the ITC index and percent change in anterior chamber angle parameters. A vault of > 0.659 mm was found to be optimal for angle-closure suspect with a sensitivity of 85.2% and a specificity of 53.9%.

CONCLUSIONS

Anterior chamber angle parameters decreased one month after ICL implantation, and their percentage changes and ITC index correlated with the vault. When the vault is larger than 0.659 mm, it is necessary to be alert to possible closed angle suspicion.

Evaluation of phakic intraocular lens power calculation using the new Linz-Homburg-Castrop formula and comparison with four conventional methods

PURPOSE

To evaluate the accuracy of phakic intraocular lens (pIOL) power calculation in a middle European patient cohort.

SETTING

EyeLaser Clinic, Linz, Austria.

DESIGN

Single-center single-surgeon retrospective consecutive case series.

METHODS

Patients were included after uneventful pIOL surgery implanting 91 nontoric and toric Visian implantable collamer lens model V4c. Online Calculation and Ordering System (OCOS) software, JPhakic software, Olsen-Feingold formula, Holladay formula, and Linz-Homburg-Castrop (LHC) formula were compared. When possible, lens constants were optimized for the patient cohort. Data of single eye per patient were included. Outcome measures were mean absolute prediction error, median absolute prediction error, mean prediction error with SD, and median prediction error, as well as the percentage of eyes with an absolute prediction error within limits of 0.25 diopters (D), 0.5 D, 0.75 D, and 1.0 D.

RESULTS

91 eyes of 91 patients were assessed. After application of the Cochran Q test, the Olsen-Feingold formula achieved a significantly lower percentage of eyes within an absolute prediction error of 1.0 D than all other methods.

CONCLUSIONS

In the patient cohort, OCOS software, JPhakic software, and Holladay and LHC formulas showed equal results and can be cross-checked. The LHC formula was not published before. A ready-to-use Excel sheet is available as an addendum.

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.

A meta-analysis of visual outcomes and optical quality after small incision lenticule extraction versus implantable collamer lens for myopia

OBJECTIVE

To evaluate possible differences in visual outcome and optical quality when small incision lenticule extraction (SMILE) versus implantable collamer lens (ICL) is used to correct myopia.

METHODS

PubMed, EMBASE, and the Cochrane Central Register of Controlled Trials were searched up to August 2021 to identify relevant studies. The PRISMA guidelines were followed. Primary outcomes were postoperative efficacy, safety, and predictability at the end of follow-up. Secondary outcomes were changes in modulation transfer function cutoff frequency (MTF _cut-off), objective scatter index (OSI) values, total higher-order aberrations (HOAs), spherical aberrations, and coma aberrations.

RESULTS

Seven studies with a total of 1296 eyes (SMILE: 731 eyes; TECXL: 565 eyes) were included. The ICL group had a better MTF _cut-off (P = 0.007) and less change in the proportion of HOAs (P < 0.001), spherical aberrations (P = 0.009), and coma (P = 0.006) than the SMILE group. For the other outcomes, there were no statistically significant differences.

CONCLUSIONS

SMILE and ICL implantation are comparable in efficacy, safety, and predictability for correcting myopia. Larger studies with longer follow-up times are warranted to provide a better understanding of the benefits of SMILE and ICL implantation.

The Impact of Corneal Epithelial Thickening and Inhomogeneity on Corneal Aberrations After Small Incision Lenticule Extraction

PURPOSE

To investigate the corneal epithelial remodeling profile after small incision lenticule extraction (SMILE), the correlated explanatory variables, and its potential impact on corneal higher order aberrations (HOAs).

METHODS

This single-center study prospectively evaluated 75 right eyes of 75 patients scheduled for SMILE. An anterior segment optical coherence tomography device was used to automatically obtain central 6-mm corneal epithelial thickness (ET), total corneal HOAs, and individual Zernike components before and after surgery. The ET inhomogeneity over the central 3- and 6-mm cornea was quantified with coefficient of variance (CV).

RESULTS

Both ET and CV significantly increased 1 month postoperatively (all P < .05). The stepwise multiple regression analysis showed that ET and CV were significantly correlated with preoperative ET and CV, respectively (all P < .01). The corrected spherical equivalent also significantly influenced ET and CV (all P < .01). Over the central 6-mm zone, the alterations of total corneal HOAs and individual Zernike components such as vertical coma (Z7) and spherical aberration (Z12, Z24) were significantly correlated with ET and CV (all P < .05).

CONCLUSIONS

The SMILE-induced epithelial remodeling involved both ET and ET inhomogeneity. The modulation was associated with preoperative and treatment parameters, and exerted a significant impact on corneal HOA alterations especially over the central 6-mm cornea. Together with the amount of correction and corneal curvature gradient change, preoperative assessment of ET and ET inhomogeneity might help predict postoperative epithelial remodeling. [J Refract Surg. 2023;39(1):23-32.].

Intraocular Implantable Collamer Lens with a Central Hole Implantation: Safety, Efficacy, and Patient Outcomes

This review summarizes the available literature and provides updates on the efficacy, safety, and patient outcomes of phakic intraocular lens implantation using implantable collamer lens (ICL), with a focus on newer models with a central port (EVO/EVO+ Visian Implantable Collamer Lens, STAAR Surgical Inc.). All studies included in this review were identified from the PubMed database and were reviewed for relevancy of their topic. Data on hole-ICL implantation performed between October 2018 and October 2022 in 3399 eyes showed a weighted average efficacy index of 1.03 and a weighted average safety index of 1.19 within an average follow-up of 24.7 months. The incidence of complications such as elevated intraocular pressure, cataract, and corneal endothelial cell loss was low. Moreover, both quality of vision and quality of life improved after ICL implantation, confirming the benefits of this procedure. In conclusion, ICL implantation is a promising refractive surgery alternative to laser vision correction with excellent efficacy, safety, and patient outcomes.

Early Assessment of Circumferential Anterior Segment Structures Following Implantable Collamer Lens V4c Implantation Via SS-OCT

Purpose

To explore early changes in circumferential anterior segment structures following Implantable Collamer Lens (ICL) V4c implantation via swept-source optical coherence tomography (SS-OCT).

Methods

In 103 eyes of 56 myopic patients undergoing ICL V4c surgery, anterior segments were measured via SS-OCT to compute local anterior chamber angle (ACA) parameters on the nasal–temporal (0°–180°), superior–inferior (90°–270°), and superior nasal–inferior temporal (80°–260°) meridians, including angle-opening distance at 500 µm (AOD500), trabecular–iris space area at 500 µm (TISA500), trabecular–iris angle at 500 µm (TIA500), and circumferential ACA parameters, including AOD area at 500 µm (AODA500), trabecular–iris circumference volume at 500 µm (TICV500), and the index and area of iris–trabecular contact (ITC). ACA parameters were compared preoperatively and at 1 week, 1 month, and 3 months postoperatively and compared among quadrants. Mixed-effects model was used to evaluate the parameters correlated with the post-ITC parameters.

Results

The mean AOD500, TISA500, TIA500, AODA500, and TICV500 were decreased by 65.4% to 71%, 64.1% to 69.3%, 53.8% to 61.5%, 69.9%, and 69.2%, respectively, at 1 week postoperatively. The ITC index and area values rose from 1.436% ± 4.427% and 0.070 ± 0.254 mm² to 12.343% ± 13.216% and 0.903 ± 1.304 mm² (all P < 0.05). No further decreases in ACA parameters were observed beyond 1 week postoperatively (all P > 0.05). Significant differences were observed among quadrants, with the narrowest in the superior–nasal quadrant, followed by the superior quadrant. The 3-month vault was significantly correlated with the ITC index and area at 3 months postoperatively.

Conclusions

Anterior segment structures were significantly shallow at 1 week with no further decreases thereafter. In light of anatomical variability, we recommend circumferential meridian scan to assess angle status, with special attention to the superior–nasal and superior quadrants.

Translational Relevance

We investigated the early changes in circumferential anterior segment structures following ICL V4c implantation, thus providing a better perspective for understanding anterior segment structural characteristics after ICL V4c surgery.

Prediction of excessively low vault after implantable collamer lens implantation using iris morphology

Purpose

To identify the iris morphology-related factors for prediction of outcomes of excessively low vault (< 100 μm) after Implantable Collamer Lens V4c (ICL V4c; STAAR Surgical) implantation.

Methods

This retrospective case-control study included 81 eyes from 2,080 patients who underwent ICL implantation. Twenty-seven eyes of 27 patients with excessively low vault (< 100 μm) constituted the case group (excessively low vault group). Patients with vault (250 to 750 μm) were selected as the optimal vault group by matching anterior chamber depth, white-to-white distance and ICL size with cases with excessive low vault (< 100 μm) at a proportion of 1:2. The preoperative biometric parameters and postoperative vault were recorded. Multiple linear regression analysis was performed to assess the relationship between the postoperative vault and various variables. Conditional logistic regression analysis was used to estimate the risk factors for excessively low vault.

Results

The postoperative vault was associated with preoperative pupil diameter (PD), crystalline lens rise, iris concavity and the ratio of the iris concavity to chord length (P < 0.05). The larger iris concavity increased risk of excessively low postoperative vault (< 100 μm) (OR = 81.10; 95%CI = 2.87 to 2296.58; P = 0.01).

Conclusions

Eyes with obviously concave iris were associated with a higher rate of excessively low vault (< 100 μm). Evaluation of iris morphology may provide significant information for predicting excessive postoperative vault.

Implantable collamer lens implantation (ICL) versus small incision lenticule extraction (SMILE) in low to moderate myopia: study protocol for a randomized, non-inferiority trial

BACKGROUND

Implantable collamer lens implantation (ICL) is a form of 'foldable' posterior chamber phakic intraocular lens refractive surgery that generally does not impair cornea and natural accommodation. The potential advantages of the ICL over keratorefractive laser procedures include less induction of higher-order aberrations (HOAs) and enhanced retinal image magnification. On the other hand, small incision lenticule extraction (SMILE), currently, one of the most popular refractive surgery procedures, also offers excellent visual outcomes, particularly for eyes with low to moderate amounts of myopia. The aim of this study is to evaluate whether ICL/TICL (toric ICL) is comparable to SMILE for low to moderate myopia in terms of refractive outcomes at 3 and 18 months post-operatively.

METHODS/DESIGN

This is a prospective randomized study. A total of 300 participants will be randomized into two groups, the ICL/TICL group and SMILE group. Eligible participants with spherical equivalent (SE) less than - 6.0 diopter (D) will be recruited. Following randomization, participants will be followed at 1, 3, 6, 12, and 18 months. The primary outcome is the refractive predictability at every postoperative point after surgery, which is the proportion of the number of eyes achieving a postoperative SE within ± 0.5 D and ± 1.0 D of the intended target. Secondary outcome parameters include visual acuity, refraction, adverse events, and quality of vision measurements.

DISCUSSION

This trial will provide information on whether ICL has comparable, if not superior, refractive outcomes compared to the established SMILE for low to moderate myopia, thus providing evidence for translation into clinical practice.

TRIAL REGISTRATION

Chinese clinical trial registry (ChiCTR) 2200055372. Registered on 08 January 2022.

Influence of Ocular Residual Astigmatism on the Correction of Myopic Astigmatism by Toric Implantable Collamer Lens: A Comparative Study With Femtosecond Laser Small Incision Lenticule Extraction

Purpose

To evaluate the influence of the origin of astigmatism on the correction of myopic astigmatism by toric implantable collamer lens (TICL) and compare it with femtosecond laser small incision lenticule extraction (SMILE).

Methods

Ocular residual astigmatism (ORA) was determined by vector analysis using manifest refraction and Scheimpflug camera imaging of the anterior cornea. One-to-one matching between the TICL and SMILE groups was performed by preoperative manifest refractive astigmatism (RA) and ORA, tolerating a maximum difference of 0.50 diopter (D) for RA and 0.25 D for ORA. Patients of each group were further divided into groups according to ORA (high &gt; 1.0 D; low ≤ 1.0 D). The baseline and 12-month postoperative data were analyzed. Data are expressed as mean ± standard deviation (SD). A value of p less than 0.05 was considered statistically significant.

Results

For the TICL group, no significant differences in the postoperative RA, safety index, efficacy index, index of success (IOS), correction index (CI), and angle of error (AOE) were found between high (n = 36) and low ORA (n = 36) groups (Mann–Whitney U test, p &gt; 0.05). For the SMILE group, the postoperative RA (high: −0.67 ± 0.43 D, low: −0.39 ± 0.29 D, Mann–Whitney U test, p = 0.003) and IOS (high: 0.50 ± 0.43, low: 0.25 ± 0.23, Mann–Whitney U test, p = 0.003) were greater in the high ORA group. When comparing TICL and SMILE groups, the mean postoperative RA (TICL: −0.48 ± 0.29 D, SMILE: −0.67 ± 0.43 D, Mann–Whitney U test, p = 0.03) and IOS (TICL: 0.32 ± 0.23, SMILE: 0.50 ± 0.43, Mann–Whitney U test, p = 0.03) were significantly higher in the SMILE group when the ORA was &gt;1.0 D.

Conclusion

Both TICL and SMILE are effective in correcting myopic astigmatism. ORA has a lesser effect on TICL than on SMILE.

Comparison of Visual Outcomes and Optical Quality of Femtosecond Laser-Assisted SMILE and Visian Implantable Collamer Lens (ICL V4c) Implantation for Moderate to High Myopia: A Meta-analysis

PURPOSE

To compare visual outcomes and optical quality of femtosecond laser-assisted small incision lenticule extraction (SMILE) and Visian Implantable Collamer Lens (ICL V4c; STAAR Surgical) implantation for moderate to high myopia.

METHODS

For this systematic review and meta-analysis, the Cochrane, PubMed, Embase, and Chinese databases (Wan-fang data and CNKI) were comprehensively searched to identify studies comparing SMILE and ICL V4c implantation. Data of interest were extracted and analyzed by Stata V.16.0 software (StataCorp). The weighted mean differences and their 95% confidence intervals were used to assess the strength of the association.

RESULTS

Twelve studies incorporating 1,390 eyes of 822 patients were included. The analysis revealed ICL V4c implantation had a significantly higher safety index and lower high order aberrations, coma, and spherical aberration than SMILE in treating moderate to high myopia (P < .05). Subgroup analysis revealed such differences were more prominent in patients with high myopia who had shorter follow-up duration. When follow-up was longer than 6 months, the differences in safety index and total HOAs became nonsignificant (P > .05). The two procedures had no difference in efficacy index, postoperative visual acuity, spherical equivalent, trefoil, Objective Scatter Index, or modulation transfer function cut-off frequency (P > .05).

CONCLUSIONS

Both SMILE and ICL V4c implantation were safe and efficient for moderate to high myopia. Compared with SMILE, ICL V4c implantation might provide better postoperative visual quality in patients with high myopia in the early postoperative period. [J Refract Surg. 2022;38(6):332-338.].

Determinants of Subjective Quality of Vision After Phakic Intraocular Lens Implantation

PURPOSE

To evaluate postoperative subjective quality of vision in patients who underwent Implantable Collamer Lens (ICL) (STAAR Surgical) implantation for correction of myopia and to identify potential predictive parameters.

METHODS

In this single-center cross-sectional study, a total of 162 eyes of 81 patients (58 women, 23 men) who underwent ICL implantation were analyzed. The Quality of Vision (QOV) questionnaire was used to assess patient-reported outcomes. Baseline characteristics (eg, age), treatment parameters (eg, surgical corrected refraction), and refractive (eg, residual refraction) and visual (eg, uncorrected distance visual acuity) outcomes were analyzed regarding their effect on QOV.

RESULTS

Mean age was 33.3 ± 7.0 years (range: 21 to 51 years) and mean preoperative spherical equivalent was -8.42 ± 2.49 diopters (D) (range: -3.25 to -14.38 D). After a mean postoperative follow-up period of 19 ± 14 months (range: 6 to 54 months), the safety index score was 1.23 ± 0.21 and the efficacy index score was 1.17 ± 0.22. The mean QOV scores were 35.5 ± 11.3, 32.2 ± 11.1, and 23.3 ± 16.1 for frequency, severity, and bothersomeness, respectively. The most frequently experienced symptoms were halos (90.1%) and glare (66.7%). Halos appeared in 66.7% of the patients "occasionally" and 5 of them (6.2%) experienced them "very often." Only 1 patient (1.2%) classified halos as "very bothersome." Patients older than 36 years reported visual symptoms more frequently (P < .05) and showed higher bothersomeness scores (P = .01).

CONCLUSIONS

Halos are the most commonly perceived long-term visual disturbance after myopic ICL implantation with a central hole. Visual symptoms can persist more than 6 months postoperatively, causing only minor disturbances in most cases. Older patients seem more prone to experiencing these symptoms. [J Refract Surg. 2022;38(5):280-287.].

A Comprehensive Investigation of Contrast Sensitivity and Disk Halo in High Myopia Treated With SMILE and EVO Implantable Collamer Lens Implantation

Purpose

To investigate the clinical outcomes in small incision lenticule extraction (SMILE) and EVO implantable Collamer lens (ICL)–treated high myopia.

Methods

Thirty-three SMILE-treated and 32 EVO ICL-treated patients were included and followed up for 6 months. Subjective refraction, contrast sensitivity, and disk halo size were measured preoperatively and postoperatively. Patient-reported outcomes (PROs) were obtained at the final visit.

Results

Significant differences in efficacy and safety indices were observed between the SMILE and EVO ICL groups at 6 months postoperatively (P < 0.05). In the SMILE group, the mesopic contrast sensitivity at 2.2 cycles per degree (cpd) and photopic contrast sensitivity at 0.5, 3.4, and 7.1 cpd were significantly improved. In the EVO ICL group, the mesopic contrast sensitivity at 7.1 cpd and photopic contrast sensitivity at 0.5, 7.1, and 14.6 cpd were significantly improved. The halo radii after SMILE were significantly increased at 1 week, showed a decreasing trend at 1 month, returned to baseline at 3 months, and progressed stably at 6 months. However, it was unchanged in the EVO ICL group. Regarding subjective experience, haloes were the most common disturbance with mild and little bothersomeness after EVO ICL in contrast to starbursts after SMILE.

Conclusions

EVO ICL implantation yielded better visual outcomes, improved contrast sensitivity particularly at high spatial frequencies, had a stabler disk halo size, and increased incidence of haloes, with less influence than that of SMILE.

Translational Relevance

The disk halo and PRO findings will be of benefit for consultations and evaluations in visual performance and disturbances.

Influence of Ocular Residual Astigmatism and Target-Induced Astigmatism on the Efficacy of the Implantation of a Toric Implantable Collamer Lens With Central Hole for Myopic Astigmatism Correction

Purpose

To investigate the effects of ocular residual astigmatism (ORA) and target-induced astigmatism (TIA) on the efficacy of toric implantable collamer lens (TICL) with central hole for myopic astigmatism correction.

Methods

Retrospective case series. One hundred and eighteen eyes implanted with a TICL (V4c) from 118 patients were included. Subjective refraction and corneal topography were examined preoperatively, at 1 and 12 months postoperatively. The eyes were divided into the low-ORA ( ≤ 0.5 D) and high-ORA (&gt;0.5 D) groups based on vector analysis, and into the low-TIA (≥0.75D and &lt;2 D) and the high-TIA (≥2 D and ≤ 4 D) groups according to preoperative refractive astigmatism. Correction index (CI) and index of success (IOS) were compared between different groups.

Results

All surgeries were uneventful, and no complications occurred during follow-up. At 1 and 12 months postoperatively, no significant differences were found in CI or IOS values between the high and low ORA groups, while significantly higher CI and lower IOS were detected in the high-TIA group than in the low-TIA group (P &lt; 0.05). No significant difference was found in CI between 1 and 12 months postoperatively in either group (P &gt; 0.05). However, significantly lower IOS was found at 12 months compared with 1 month postoperatively for each group (P &lt; 0.05).

Conclusions

Toric implantable collamer lens (TICL) implantation is effective in correcting myopic astigmatism and is more effective in eyes with high TIA, while ORA has a minor effect.

Safety of intraocular pressure measurement using air-puff tonometer following implantable Collamer lens implantation

PURPOSE

To determine the safety of intraocular pressure (IOP) measurement using a non-contact tonometer in patients who have undergone implantable collamer lens (ICL) implantation.

SETTING

Eye Ear Nose and Throat Hospital.

DESIGN

Prospective study.

METHODS

Sixty-four eyes of 33 patients (aged 28.4±5.2 years) scheduled for ICL implantation were enrolled. The anterior segment parameters and vault were obtained using an anterior segment analyzer. A non-contact air-puff tonometer was employed before surgery, as well as 1 day and 1 week after surgery, to assess corneal biomechanical properties and intraocular pressure (IOP). Meanwhile, the Corvis ST was applied to evaluate the distance between the corneal endothelial layer and iris (E-Iris Dist), as well as the distance between the corneal endothelial layer and ICL (E-ICL Dist) when the cornea was deformed by the airflow.

RESULTS

The mean anterior chamber depth (ACD), anterior chamber volume (ACV), and anterior chamber angle (ACA) decreased significantly after surgery (all P-values < 0.001). The E-ICL Dists measured 1 day and 1 week postoperatively were similar (P=0.107). However, a contact between the corneal endothelium and ICL was detected in two eyes when the cornea was deformed to the highest concavity. The 1 day postoperative vault, ACV, ACA, and preoperative SSI contributed significantly (P=0.001, P=0.023, P=0.010, and P=0.019, respectively) to determine the distance. The mean E-iris Dists decreased significantly at 1 day and 1 week after operation (P<0.001). The 1-week postoperative vault and ACD contributed significantly (P=0.025 and P=0.039, respectively) to determine the E-Iris Dist value.

CONCLUSIONS

Excessively high vault, shallow ACD, narrow ACA, low ACV, and soft cornea are associated with a lower E-ICL distance, and thus may be risk factors for a contact between the corneal endothelium and ICL during IOP measurement. Although there is no proof that the contact may cause any risks to the endothelium, we recommend avoiding non-contact air-puff tonometry in eyes predicted by our model to be at risk of this occurring. Contact IOP measurements using goldmann applanation tonometers or dynamic contour tonometers may be alternate methods of IOP measurements in extreme cases.

Implantable collamer lens versus small incision lenticule extraction for high myopia correction: A systematic review and meta-analysis

Purpose

To compare the efficacy, safety, predictability and visual quality between implantable collamer lens (ICL) implantation and small incision lenticule extraction (SMILE) for high myopia correction in adults.

Methods

A systematic review and meta-analysis was conducted. A comprehensive literature search was done based on databases including PubMed, Science Direct, Embase, and the Cochrane Central Register of Controlled Trials. The efficacy index, safety index, changes in Snellen lines of corrected distance visual acuity (CDVA), predictability (difference between post-operative and attempted spherical equivalent error, SER), incidence of halos, and change in higher-order aberrations (HOAs) were compared. Mean difference (MD) and 95% confidence interval (CI) was used to estimate continuous outcomes, risk ratio (RR) and 95%CI was used to estimate categorical outcomes.

Results

Five observational studies involving 555 eyes were included in this review. Studies’ sample sizes (eyes) ranged from 76 to 197. Subjects’ refraction ranged from -6 diopter (D) to -12D. Study duration of most researches were 6 months or 12 months. Compared to SMILE, ICL implantation showed better efficacy index (MD=0.09, 95%CI:0.01 to 0.16) and better safety index (MD=0.08, 95%CI: 0.00 to 0.16). Compared with SMILE, more ICL-treated eyes gained one or more Snellen lines of CDVA (RR=1.54, 95%CI:1.28 to 1.86), more gained two or more lines (RR=2.09, 95%CI:1.40 to 3.13), less lost one or more lines (RR=0.17, 95%CI:0.05 to 0.63). There was no difference in predictability between two treatments, RRs of predictability of within ±0.5D and ±1D were 1.13 (95%CI: 0.94 to 1.36) and 1.00 (95%CI: 0.98 to 1.02). Compared with SMILE, ICL implantation came with a higher risk of halos [RR=1.79, 95%CI: 1.48 to 2.16] and less increase in total HOAs (MD=-0.23, 95%CI: -0.42 to -0.03).

Conclusion

Compared with SMILE, ICL implantation showed a higher risk of halos, but equal performance on SER control, and better performance on efficacy index, safety index, CDVA improvement and HOAs control. Overall, ICL implantation might be a better choice for high myopia correction in adults.

Long-term Comparison of Vault and Complications of Implantable Collamer Lens with and without a Central Hole for High Myopia Correction: 5 Years

PURPOSE

To investigate the long-term safety, efficacy, stability, vault, and complications of implantable collamer lens with (ICL V4c) and without (ICL V4) a central hole for correcting high myopia.

METHODS

78 eyes (40 patients) underwent ICL V4c implantation and 78 eyes (48 patients) underwent ICL V4 implantation were enrolled. They were followed up for 5 years of the uncorrected and corrected distance visual acuity, spherical equivalent (SE), axial length, intraocular pressure, endothelial cell density and vault.

RESUITS

The safety indices of the ICL V4c and V4 groups at 5 years were 1.25 ± 0.40 and 1.31 ± 0.40, respectively (P = .353). The efficacy indices were 0.90 ± 0.29 and 1.00 ± 0.44, respectively (P = .098). The preoperative, 1 month and 5 year postoperative logMAR UDVAs were respectively 1.54 ± 0.48, 0.11 ± 0.17, and 0.20 ± 0.26 in the V4c group and 1.56 ± 0.44, 0.14 ± 0.19, and 0.22 ± 0.26 in the V4 group (P = .703, 0.329, 0.585). The logMAR CDVAs were resepectively 0.13 ± 0.18, 0.02 ± 0.11, and 0.05 ± 0.16 in the V4c group and 0.18 ± 0.22, 0.05 ± 0.14, and 0.09 ± 0.21 in the V4 group (P = .128, 0.169, 0.229). The SE were resepectively -15.10 ± 4.32 D, -0.71 ± 1.31 D and -1.65 ± 1.30 D in the V4c group and -15.44 ± 3.51 D, -0.61 ± 1.12 D and -1.40 ± 1.30 D in the V4 group (P = .585, 0.637, 0.296). The mean vault reduced by 97.31 ± 136.61 μm in the V4c group and by 99.74 ± 245.83 μm in the V4 group. Three eyes (3.85%) with mid-periphery anterior subcapsular opacification in the V4c group and two (2.56%) with cataract, one (1.28%) with central anterior subcapsular opacification in the V4 group were observed. The CDVA of 20/40 was obtained in the two cataract eyes after phacoemulcification and intraocular lens implantation.

CONCLUSION

Long-term ICL V4c and ICL V4 implantations are safe, effective, and stable for high myopia correction. ICL V4c can potentially reduce the risk of lens opacification and may be more tolerant to low vault than ICL V4.

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.

Five-year outcomes of EVO implantable collamer lens implantation for the correction of high myopia and super high myopia

Background

To evaluate the long-term safety, efficacy, predictability, and stability of implantable collamer lens with a central hole (EVO ICL) implantation for correcting high myopia (HM) and super high myopia (SHM).

Methods

This prospective study evaluated 83 eyes of 46 patients who were divided into groups based on their spherical equivalent refractive error (SE): HM group (− 12 D ≤ SE < − 6 D) and SHM group (SE < − 12 D). They were followed up for 5 years after ICL implantation; assessments of uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), manifest refractive error, axial length, intraocular pressure, corneal endothelial cell density, and vault were conducted, and a questionnaire was administered.

ResuIts

At 5 years postoperatively, the safety indices of the HM and SHM groups were 1.03 ± 0.10 and 1.32 ± 0.39, and the efficacy indices were 0.83 ± 0.25 and 0.86 ± 0.32, respectively. In the HM group, 60.47% and 79.07% of the eyes were within ± 0.50 D and ± 1.00 D of the attempted correction, while it was achieved for 22.50% and 47.50% of the eyes in the SHM group, respectively. The SE of the HM group decreased from  − 9.72 ± 1.41 D preoperatively to 0.04 ± 0.39 D 1 month postoperatively and − 0.67 ± 0.57 D 5 years postoperatively, while in the SHM group, it decreased from − 15.78 ± 3.06 D preoperatively to  − 0.69 ± 0.97 D 1 month postoperatively and − 1.74 ± 1.19 D 5 years postoperatively.

Conclusion

EVO ICL implantation is safe, effective, and predictable for correcting HM and SHM. CDVA improved more after surgery for SHM, but the growth of axial length still needs attention.

Effect of the Difference Between the White-to-White and Sulcus-to-Sulcus on Vault and the Related Factors After ICL Implantation

INTRODUCTION

To assess the differences between the horizontal white-to-white (WTW) and horizontal sulcus-to-sulcus (STS) diameter measurements, their related factors, and their effects on vault after implantable Collamer lens (ICL) implantation.

METHODS

This retrospective study included 429 eyes of 429 patients (145 men and 284 women with a mean age of 29.22 ± 8.06 years) who underwent ICL implantation. The choice of the ICL size depended on the WTW diameter and anterior chamber depth (ACD). The information of WTW diameter, STS diameters, ACD, and their relationships on vault were analyzed.

RESULTS

Horizontal STS and WTW diameters were correlated (r = 0.71, P < 0.001). The mean difference between the STS and WTW diameters was -0.02 ± 0.33 (-1.36 to 1.11) mm. The average vaults of the ^△STS-WTW < -0.1 group, - 0.1 ≤ ^△STS-WTW ≤ 0.1 group, and ^△STS-WTW > 0.1 group were 558.36 ± 163.58 (250-1100) μm, 513.10 ± 121.42 (190-850) μm, and 469.01 ± 133.23 (120-750) μm, respectively. There were significant differences between these groups (P < 0.05). ^△STS-WTW was correlated with the horizontal STS diameter (r = 0.30, P < 0.001), the WTW diameter (r = -0.17, P = 0.001), and the ACD (r = 0.17, P < 0.001). When the WTW diameter was further away from 11.08 to 12.51 mm or the ACD was further away from 2.81 to 3.74 mm, the difference between the STS and WTW diameters was larger and the correlation between the STS and WTW diameters was weaker.

CONCLUSIONS

The difference between the WTW and STS diameters was larger for cases with a WTW diameter or anterior chamber depth outside a certain range; this may be associated with an undesirable vault after ICL implantation. Special attention should be paid to these patients.

In vivo optical quality of posterior-chamber phakic implantable collamer lenses with a central port

BACKGROUND

The aim of this review is to summarize the optical quality results in patients following the implantation of the V4c implantable collamer lens with a central port (ICL, STAAR Surgical Inc.).

MAIN TEXT

A literature search in several databases was carried out to identify those publications, both prospective, retrospective and/or comparative with other refractive surgery procedures, reporting optical outcomes of patients who were implanted with the V4c ICL model. A total of 17 clinical studies published between 2012 and 2021 were included in this review. A detailed analysis of the available data was performed including number of eyes, follow-up and preoperative spherical equivalent. Specifically, the review focused on several optical parameters including higher-order aberrations (HOAs), modulation transfer function (MTF) cut-off frequency and Strehl ratio. This review encompassed a total of 817 eyes measured using different optical devices based on Hartmann-Shack, retinal image quality measurement and ray-tracing technologies at different follow-ups.

CONCLUSIONS

The outcomes found in this review lead us to conclude that the ICL V4c model provides good optical quality, by means of different metrics, when implanted.

Comparison of visual outcomes after non-toric and toric implantable collamer lens V4c for myopia and astigmatism

PURPOSE

To evaluate the visual quality of myopic patients after non-toric versus toric implantable collamer lens (ICL and TICL, respectively) V4c, and to investigate the potential risk factors of postoperative night vision disturbances.

METHODS

This prospective cohort study included 42 eyes of 21 patients treated with ICL and 46 eyes of 23 patients treated with TICL. Refractive parameters and ocular aberrations were examined before and 6 months after surgery. Subjective quality of vision was scored by a validated questionnaire.

RESULTS

The efficacy index at 6 months was 1.14 ± 0.20 for ICL and 1.17 ± 0.16 for TICL; the safety index was 1.20 ± 0.17 for ICL and 1.20 ± 0.19 for TICL. The root mean square of total higher-order aberrations (HOAs) and trefoil was significantly increased, and no statistical differences between groups were detected in HOA changes. Many patients reported haloes (85.7% for ICL and 100% for TICL) and glare (76.2% for ICL and 65.2% for TICL), but most (94.4% for ICL and 95.5% for TICL) were satisfied or very satisfied with visual outcomes. Implantable collamer lens (ICL) toricity was the risk factor for frequency (OR = 2.81, p = 0.01), severity (OR = 3.85, p = 0.003) and bothering effect (OR = 2.89, p = 0.01) of haloes.

CONCLUSIONS

Implantable collamer lens and TICL provided comparable efficacy, safety and predictability, induced acceptable level of HOAs and achieved high satisfaction in correcting myopia and myopic astigmatism. Although not severe, haloes and glare have a non-negligible prevalence and ICL toricity is a potential risk factor of haloes.

Comparative study of small-incision lenticule extraction and phakic intraocular lens implantation for the correction of high myopia: 6-year results

PURPOSE

To compare the long-term safety, efficacy, and complications of small-incision lenticule extraction (SMILE) and flexible iris-fixated anterior chamber phakic intraocular lens (pIOL) implantation for the treatment of high myopia.

SETTING

University of Health Science Turkey, Beyoğlu Eye Training and Research Hospital, İstanbul, Turkey.

DESIGN

Retrospective comparative case series.

METHODS

Data of patients who underwent SMILE or pIOL (Artiflex) implantation for myopia were retrospectively reviewed. Only patients with preoperative manifest refraction spherical equivalent from -6.00 to -10.00 diopters (D) were included in the study.

RESULTS

There were 47 eyes of 32 patients in the SMILE group and 52 eyes of 29 patients in the pIOL group. The mean postoperative follow-up was 63.75 ± 18.40 months in the SMILE group and 65.38 ± 16.22 months in the p-IOL group (P = .71). At 6 years postoperatively, refractive predictability was slightly better in the pIOL group, and the percentages of eyes within ±0.50 D of the attempted correction were 77% and 83% in the SMILE and pIOL groups, respectively. Although mean uncorrected distance visual acuity was comparable (SMILE, 0.12 ± 0.06 logarithm of the minimum angle of resolution [logMAR]; p-IOL, 0.09 ± 0.05 logMAR), the safety indices (1.08 ± 0.22 vs 1.11 ± 0.20; P = .02) and the efficacy indices (0.92 ± 0.24 vs 1.11 ± 0.22; P = .03) were statistically significantly higher after pIOL implantation. Despite a mean of 11.09% of the endothelial cell being lost at 6 years after pIOL implantation, no pIOL was explanted due to endothelial cell loss.

CONCLUSIONS

In this comparative and long-term study, iris-fixated anterior chamber pIOL implantation for high myopic correction showed slightly better safety and efficacy profiles but with statistically significant endothelial cell loss.

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.

Visual outcomes after small incision lenticule extraction and implantable collamer lens V4c for moderate myopia: 1-year results

PURPOSE

To compare 1-year visual outcomes after implantable collamer lens V4c (EVO-ICL) implantation and small incision lenticule extraction (SMILE) for moderate myopia.

METHODS

In this retrospective study, 67 eyes of 39 patients with a preoperative manifest refraction spherical equivalent between - 3.00 and - 6.00 diopters (D) were selected from a database of SMILE and ICL implantation procedures performed from April 2018 to December 2018. Thirty-two eyes of 20 patients underwent EVO-ICL implantation, and 35 eyes of 19 patients underwent SMILE. At the routine 1-year follow-up appointment, all selected patients were examined for higher-order ocular aberrations, retinal image quality, and a quality of vision (QoV) questionnaire. This data was then analyzed.

RESULTS

No complications were observed. Uncorrected and corrected visual acuities at 1 year after surgery were - 0.13 ± 0.07 and - 0.15 ± 0.06 logMAR in the SMILE group, and - 0.10 ± 0.07 and - 0.16 ± 0.05 logMAR in the ICL group. Twenty-nine eyes (90.6%) which underwent ICL implantation and 34 eyes (97.1%) which underwent SMILE were within ± 0.5 D of the attempted spherical equivalent (P = 0.49). Changes in coma after ICL were significantly less than after SMILE (P = 0.002). The leading complaints after ICL and SMILE were halos (84.4%) and blurred vision (65.7%), respectively.

CONCLUSIONS

Both SMILE and ICL implantation provided good safety, efficacy, and predictability in correcting moderate myopia. The subjective visual complaints consisted mainly of halos after ICL and starbursts and blurred vision after SMILE.

Peripheral Anterior Chamber Depth and Angle Measurements Using Pentacam After Implantation of Toric and Non-toric Implantable Collamer Lenses

Purpose: To evaluate the characteristics of peripheral anterior chamber measurements by Pentacam after posterior implantable collamer lenses (ICL) and toric ICL (TICL) with central hole (V4c) implantation.

Methods: Prospective, non-randomized consecutive case series. Forty-six patients undergoing ICL implantation in one eye (Group A) and identically sized TICL in the contralateral eye (Group B) in the Refractive Surgery Center of Eye and ENT Hospital of Fudan University were prospectively included. According to ICL/TICL size, these eyes were further divided into four subgroups. Peripheral anterior chamber depth (PACD) and angle (ACA) in nasal and temporal sides were measured using Pentacam pre-operatively and 12-month post-operatively.

Results: The safety indices were 1.34 ± 0.32 and 1.25 ± 0.16 and the efficacy indices were 1.20 ± 0.24 and 1.19 ± 0.19 for ICL and TICL groups, respectively. There was no significant difference in pre-operative PACD or ACA between the two groups. Post-operative PACD and ACA were significantly lower than pre-operative values. Variations of PACD and ACA of TICL group were significantly larger than those of ICL group. The change of ACA for 13.2 mm lenses was significantly larger than that of 12.6 mm lenses. Pre-operative CACD and vault were significantly associated with post-operative PACD, while pre-operative ACA and vault were significantly associated with post-operative ACA.

Conclusions: Variations of PACD and ACA were greater in eyes after TICL (V4c) implantation compared with identically sized ICL (V4c) implantation and with larger size than smaller size lens implantation. Pre-operative anterior chamber structure and vault affect post-operative PACD and ACA.