Secondary IOL implantation for an aphakic patient with congenital cataract living in Bonin Islands; follow-up study.

Introduction: We previously reported a case of a patient with bilateral congenital cataract identified in the Ogasawara village, Bonin Islands, Japan, on a visit by an ophthalmologist and describe its course over 17 years from initial surgery. Here, we report on a secondary intraocular lens (IOL) implantation that was subsequently performed at 22 years and 5 months of age. Methods: After cataract surgery at 7 months, the aphakic patient began amblyopia treatment using extended-wear soft contact lenses (SCLs). After 10 years of age, SCLs were chosen to achieve crossed monovision considering the cosmetic appearance when facing other people. At 22 years of age, a secondary IOL implantation was performed. Secondary implant in the patient considered appearance and postoperative vision without glasses, we selected the crossed monovision method using a monofocal IOL. The postoperative targeted refraction for the right (non-dominant eye) and left eyes (dominant eye) planed - 0.33D and - 2.25D, respectively. Results: At 3 months after surgery, the corrected distance visual acuity (CDVA) with IOLs for the right and left eyes was 20/16 and 20/60, respectively, and the binocular visual acuity was 20/16 for distant vision and 20/25 for near vision. The CDVA for the right eye was: 20/13 × IOL = sph-0.25D and that for the left eye was: 20/13 × IOL = sph -1.75D D/cyl -0.50D/Ax170°. Although the exotropia was complicated by dissociated horizontal deviation and dissociated vertical deviation, there were no significant changes in ocular position before and after surgery. The patient was satisfied with achieving independence from spectacles and SCLs. Conclusion: The use of the crossed monovision method with monofocal IOLs in this patient and defective binocular function created a visual environment with no inconvenience in everyday life after secondary IOL implantation. In terms of secondary implant after amblyopia treatment, the IOL type or postoperative targeted refraction must be chosen to maintain or improve the visual environment obtained with the amblyopia treatment.

Reply to Cione et al. Comment on "Iida et al. Development of a New Method for Calculating Intraocular Lens Power after Myopic Laser In Situ Keratomileusis by Combining the Anterior-Posterior Ratio of the Corneal Radius of the Curvature with the Double-K Method. J. Clin. Med. 2022, 11, 522".

We appreciate the insightful comments [...].

A Nationwide Multicenter Study on 1-Year Outcomes of Posterior Chamber Phakic Intraocular Lens Implantation for Low Myopia.

Purpose: To assess the nationwide multicenter outcomes of posterior chamber phakic intraocular lens implantation with a central hole (EVO-ICL, STAAR Surgical) for patients with low myopia. Methods: This multicenter study comprised 172 eyes of 111 consecutive patients undergoing hole ICL implantation to correct low myopia and myopic astigmatism [manifest spherical equivalent (MSE);-3 diopters (D) or less] at seven nationwide major surgical facilities. We retrospectively determined safety, efficacy, predictability, stability, and adverse events at 1 week, 1, 3, 6, and 12 months postoperatively, and at the final visit. Results: The mean follow-up period was 1.4 ± 1.0 years. Uncorrected and corrected visual acuities at 1 year postoperatively were -0.17 ± 0.12 and -0.24 ± 0.07 logarithm of the minimal angle of resolution (logMAR), respectively. At 1 year postoperatively, 91% and 100% of eyes were within 0.5 and 1.0 D of the target correction, respectively. No significant manifest refraction changes of -0.07 ± 0.26 D occurred from 1 week to 1 year. No vision-threatening complications occurred at any time in this series. Conclusions: According to our experience, the EVO-ICL performed well without significant complications throughout the 1-year observation period, even for the correction of low myopia. It is suggested that current ICL implantation is one of the viable surgical options for correcting low myopia.

Posterior chamber phakic intraocular lens implantation after laser in situ keratomileusis.

BACKGROUND: To assess the multicenter outcomes of posterior chamber phakic intraocular lens implantation with a central hole (EVO-ICL, STAAR Surgical) for patients undergoing previous laser in situ keratomileusis (LASIK). METHODS: This case series enrolled 31 eyes of 21 consecutive patients undergoing EVO-ICL implantation to correct residual refractive errors after LASIK at 7 nationwide major surgical sites. We investigated safety, efficacy, predictability, stability, and adverse events at 1 week, 1, 3, and 6 months postoperatively, and at the final visit. RESULTS: The mean observation period was 1.6 ± 1.8 years. Uncorrected and corrected visual acuities were - 0.14 ± 0.11 and - 0.22 ± 0.09 logMAR at 6 months postoperatively. At 6 months postoperatively, 81% and 100% of eyes were within ± 0.5 D and ± 1.0 D, respectively, of the targeted correction. We found neither significant manifest refraction changes of 0.05 ± 0.38 D from 1 week to 6 months nor apparent intraoperative or postoperative complications in any case. CONCLUSIONS: Our multicenter study confirmed that the EVO-ICL provided good outcomes in safety, efficacy, predictability, and stability, even in post-LASIK eyes. Therefore, EVO-ICL implantation may be a viable surgical option, even for correcting residual refractive errors after LASIK. Trial registration University Hospital Medical Information Network Clinical Trial Registry (000045295).

Multicenter clinical outcomes of hole implantable collamer lens implantation in middle-aged patients.

To assess the multicenter clinical outcomes of the implantation of hole implantable collamer lens (Hole ICL, ICL KS-AquaPORTTM; STAAR Surgical, Nidau, Switzerland) in patients of 45 years or more. We retrospectively assessed the surgery's safety, efficacy, predictability, stability, and adverse events before surgery and after the surgery at 1 week; 1, 3, and 6 months; and 1 year, followed by once every year for approximately 2.2 years. A total of 118 eyes of 65 patients aged 45-65 years with myopic refractive errors ranging from - 2.13 to - 18.75 diopters (D) underwent hole ICL implantation and routine postoperative examinations. The average observation period was 2.2 ± 1.0 years. The safety and efficacy indices were 1.08 ±  0.21 and 0.87 ± 0.25, respectively. Manifest refraction changes of - 0.20 ± 0.43 D occurred from 1 month to the final visit after ICL implantation. Eight eyes (6.8%) developed asymptomatic anterior subcapsular cataract (ASC) immediately after surgery, and three eyes (2.5%) developed clinically significant symptomatic nuclear cataracts during the follow-up period. According to our experience, hole ICL implantation offered favorable outcomes in all measures of safety, efficacy, predictability, and stability, even in middle-aged patients, during the 2.2-year observation period.

Development of a New Method for Calculating Intraocular Lens Power after Myopic Laser In Situ Keratomileusis by Combining the Anterior-Posterior Ratio of the Corneal Radius of the Curvature with the Double-K Method.

BACKGROUND: A new method, the Iida-Shimizu-Shoji (ISS) method, is proposed for calculating intraocular lens (IOL) power that combines the anterior-posterior ratio of the corneal radius of the curvature after laser in situ keratomileusis (LASIK) and to compare the predictability of the method with that of other IOL formulas after LASIK. METHODS: The estimated corneal power before LASIK (Kpre) in the double-K method was 43.86 D according to the American Society of Cataract and Refractive Surgery calculator, and the K readings of the IOL master were used as the K values after LASIK (Kpost). The factor for correcting the target refractive value (correcting factor [C-factor]) was calculated from the correlation between the anterior-posterior ratio of the corneal radius of the curvature and the refractive error obtained using this method for 30 eyes of 30 patients. RESULTS: Fifty-nine eyes of 59 patients were included. The mean values of the numerical and absolute prediction errors obtained using the ISS method were -0.02 ± 0.45 diopter (D) and 0.35 ± 0.27 D, respectively. The prediction errors using the ISS method were within ±0.25, ±0.50, and ±1.00 D in 49.2%, 76.3%, and 96.6% of the eyes, respectively. The predictability of the ISS method was comparable to or better than some of the other formulas. CONCLUSIONS: The ISS method is useful for calculating the IOL power in eyes treated with cataract surgery after LASIK.

Multicenter survey on implantable collamer lens dislocation.

This study aimed to investigate the incidence, patient background, and postoperative prognosis of implantable collamer lens (ICL) dislocation. We retrospectively reviewed all cases of ICL dislocation at four major refractive surgery centers in Japan until December 2019. The incidence, patient background, cause of dislocation, complications of repositioning surgery, and postoperative visual function were investigated. Seven ICL dislocations [0.072% of total ICL-implanted eyes (9775 eyes)] occurred at an average of 28.6 months (11-82 months) postoperatively. All patients were male. Five eyes were injured during sports activities, one due to a fall from a bicycle, and another due to ocular blunt trauma caused by a mortuary tablet. Two patients had re-dislocation in the same eye. Retinal detachment occurred after repositioning surgery in one patient, and scleral buckling surgery was performed without ICL removal. ICL dislocation is a rare complication of ICL surgery; repositioning surgery is effective, but retinal complications may occur.

Assessment of the Vault After Implantable Collamer Lens Implantation Using the KS Formula.

PURPOSE: To examine the vault size after Implantable Collamer Lens (ICL) (KS-AquaPORT; STAAR Surgical) surgery using the KS formula. METHODS: In this prospective study, the postoperative vault was examined using the KS formula in 121 eyes of 65 patients (28 men and 37 women) who underwent ICL implantation for myopia and myopic astigmatism. The mean horizontal angle-to-angle (ATA), anterior chamber depth, and axial length before surgery were 11.83 ± 0.40, 3.25 ± 0.34, and 26.52 ± 1.17, respectively. Anterior segment optical coherence tomography (CASIA2; Tomey Corporation) was used for ATA measurement. RESULTS: Multiple regression analysis of the potential factors influencing the predicted vault error (postoperative vault - predicted vault by KS formula) showed that only ICL size was a significant factor (P < .001, r = 0.36). At an ICL size of 12.1 mm, the postoperative vault was smaller than the predicted vault, and the postoperative vault tended to be larger than the predicted vault at ICL sizes of 13.2 and 13.7 mm. CONCLUSIONS: Vault prediction by the KS formula was generally good, but the ICL size influenced the vault prediction error; therefore, a modified KS formula was created to reduce the error in measurements of the postoperative vault. [J Refract Surg. 2021;37(9):636-641.].

Evaluation of Eye Alignment before and after Cataract Surgery.

Purpose: To assess changes in eye alignment before and after cataract surgery.Subjects and methods: The medical records of 786 cataract patients without eye movement limitation who underwent bilateral cataract surgery under topical anesthesia with monofocal IOL placement were retrospectively reviewed at the Eye Center of Sanno Hospital in Japan.Results: Before cataract surgery, 121 of the 786 patients (15.4%) had constant strabismus, 263 (33.5%) had intermittent strabismus, and 402 (51.1%) had phoria. Among the 121 patients with constant strabismus on the preoperative exam, 64 (52.9%) had exotropia without vertical strabismus, 7 (5.8%) had esotropia without vertical strabismus, and 6 (5.0%) had vertical strabismus without a horizontal component. After surgery, 98 of the 786 patients (12.5%) had constant strabismus, 126 (16.0%) had intermittent strabismus, 562 (71.5%) had phoria. The rate of eye alignment agreement before and after surgery was 72.3% overall. We found that 17 patients (2.2%) who did not have constant strabismus preoperatively developed constant strabismus postoperatively, and all of these patients experienced binocular diplopia. Characteristics of patients at risk for constant strabismus and diplopia postoperatively included patients with vertical deviation preoperatively (intermittent or phoria).Conclusions: Uncomplicated cataract surgery under topical anesthesia did not influence eye alignment classification in 72.3% of patients; however, patients with vertical deviation preoperatively were more likely to transition to constant strabismus after surgery.

Eight-Year Outcomes of Implantation of Posterior Chamber Phakic Intraocular Lens With a Central Port for Moderate to High Ametropia.

Purpose: To assess the 8-year clinical outcomes of implantation of an implantable collamer lens (ICL) with a central port (KS-Aquaport; EVO-ICL) for moderate to high myopia and myopic astigmatism. Methods: This retrospective study comprised a total of 177 eyes of 106 patients with spherical equivalents of -7.99 ± 3.33 D [mean ± standard deviation], who underwent EVO-ICL implantation. We evaluated the safety, efficacy, predictability, stability, and adverse events of the surgery, at 1 month, and 1, 2, 4, 6, and 8 years postoperatively. Results: The logarithm of the minimal angle of resolution (LogMAR) uncorrected distance visual acuity (UDVA) and corrected distance visual acuity (CDVA) were -0.07 ± 0.17 and -0.20 ± 0.09, respectively, at 8 years postoperatively. The safety and efficacy indices were 1.18 ± 0.24 and 0.89 ± 0.28, respectively. At 8 years, 83 and 93% eyes were within ± 0.5 D and ± 1.0 D of the targeted correction, respectively. Change in manifest refraction from 1 month to 8 years postoperatively was -0.13 ± 0.30 D. Three eyes (1.7%) that developed cataracts had a slight pre-existing peripheral anterior subcapsular cataract formation required simultaneous ICL extraction and cataract surgery at 2 or 3 years or ICL size change (1 size up) at 7 years postoperatively. We found that neither significant intraocular pressure (IOP) rise (including pupillary block) nor significant endothelial cell loss occurred in any case throughout the 8-year observation period. Conclusions: Current ICL implantation with central port technology offered good continuous outcomes for all measures of safety, efficacy, predictability, and stability for correcting moderate to high myopic errors over a long period, thereby suggesting its long-term viability as a surgical approach for the treatment of such eyes.

Assessment of low-vault cases with an implantable collamer lens.

This study aimed to examine clinical results in low-vault eyes after implementation of a Hole implantable collamer lens (KS-AquaPORT™, STAAR Surgical Company) in terms of visual outcomes and complications over a one-year follow-up period. This was a retrospective cohort study of subjects who underwent Hole implantable collamer lens surgery at Sanno Hospital, exhibited low vault, and were followed up for 1 year. Patients were included if they met the following criteria: 20≤ age ≤55 years; stable refraction ≥6 months; -1.0 to -20.0 diopters of myopia; endothelial cell density ≥1800 cells/mm2; and no history of ocular surgery, progressive corneal degeneration, cataract, glaucoma, or uveitis. Main outcome measurements were the safety and efficacy indices, predictability, and vault. Values were indicated as the mean ± standard deviation. Subjects included 16 patients (age: 38 ± 8 years; 6 males; 25 eyes). Toric lenses were utilized for 10 eyes. Implantable collamer lens size was 12.1, 12.6, and 13.2 mm for 18, 6, and 1 eye(s), respectively. One year postoperatively, the safety index was 1.07; for 22 eyes with a target refraction of that of emmetropic eyes, the efficacy index was 0.90; and 96% of eyes were within ± 0.50 diopters of attempted versus achieved spherical equivalent correction. Postoperative vault was 142 ± 60 µm. One year postoperatively, no additional surgery was required for rotation of toric implantable collamer lens, and no advanced cataracts, increased intraocular pressure, or decreased endothelial cells were observed. In conclusion, Hole implantable collamer lens yielded satisfactory visual outcomes and no postoperative complications for low-vault eyes, suggesting its suitability for such cases.

Development of a new intraocular lens power calculation method based on lens position estimated with optical coherence tomography.

A new method is developed and validated for intraocular lens (IOL) power calculation based on paraxial ray tracing of the postoperative IOL positions, which are obtained with the use of anterior segment optical coherence tomography. Of the 474 eyes studied, 137 and 337 were grouped into training and validation sets, respectively. The positions of the implanted IOLs of the training datasets were characterized with multiple linear regression analyses one month after the operations. A new regression formula was developed to predict the postoperative anterior chamber depth with the use of the stepwise analysis results. In the validation dataset, postoperative refractive values were calculated according to the paraxial ray tracing of the cornea and lens based on the assumption of finite structural thicknesses with separate surface curvatures. The predicted refraction error was calculated as the difference of the expected postoperative refraction from the spherical-equivalent objective refraction values. The percentage error (within ±0.50 diopters) of the new formula was 84.3%. This was not significantly correlated to the axial length or keratometry. The developed formula yielded excellent postoperative refraction predictions and could be applicable to eyes with abnormal proportions, such as steep or flat corneal curvatures and short and long axial lengths.

Kinetic visual acuity, stereopsis, and ocular deviation with an implantable collamer lens.

PURPOSE: To compare kinetic visual acuity, stereopsis, ocular deviation, and fusion amplitude before and after implantable collamer lens (ICL) surgery. SETTING: Sanno Hospital. DESIGN: Retrospective analysis. METHODS: The charts of adult patients who underwent implantation of an ICL with a central aquaport (V4c) for emmetropia were reviewed. The mean preoperative spherical equivalent and subjective astigmatism were -7.87 diopters (D) ± 3.13 (SD) and -0.75 ± 0.78 D, respectively. All measurements were obtained with full refraction before surgery and without spectacle correction after surgery. The kinetic visual acuity was measured with the AS-4D device. Stereopsis and ocular deviation were measured with the Titmus Stereotest and an alternate prism cover test, respectively. Fusion amplitude was determined from breakpoints measured using a prism. RESULTS: The study comprised 29 adult patients (58 eyes). One month postoperatively, the mean safety and efficacy indices were 1.13 ± 0.20 and 0.96 ± 0.25, respectively, and 57 eyes (98.7%) were within ±0.5 D of the target correction. The mean kinetic visual acuity (logarithm of the minimum angle of resolution) was 0.30 ± 0.21 preoperatively and 0.20 ± 0.15 (Snellen 20/40 versus 20/32) postoperatively and the mean stereopsis (seconds of arc), 48.5 ± 1.6 versus 41.5 ± 1.1; both improved significantly (P < .001 and P = .012, respectively). The mean distance ocular deviation (-4.0 ± 3.8 prism diopters [Δ] versus 2.8 ± 3.6 Δ; P = .002) and near ocular deviation (-6.5 ± 6.7 Δ versus 5.4 ± 6.9 Δ; P = .04) decreased significantly. The fusion amplitude increased for near vision only. CONCLUSIONS: ICL implantation improved kinetic visual acuity and stereopsis, decreased ocular deviation, and increased near fusion amplitude.

Relationship between Crystalline Lens Thickness and Shape and the Identification of Anterior Ocular Segment Parameters for Predicting the Intraocular Lens Position after Cataract Surgery.

PURPOSE: This study was performed to investigate the relationships among crystalline lens shape, actual intraocular lens (IOL) position, and crystalline lens thickness (LT), as measured by anterior segment optical coherence tomography (AS-OCT), and to determine anterior ocular segment parameters that predict postoperative IOL position. METHODS: Seventy-nine eyes of 79 patients who underwent uneventful cataract surgery were enrolled. For crystalline lens preoperative anterior segment data, the LT, and anterior, equatorial, and posterior surface depths (ASD, ESD, and PSD, respectively) of crystalline lenses were quantitatively determined. For postoperative anterior segment data, the actual IOL position was quantified. Moreover, the following correlations were analyzed: LT with the ASD, ESD, PSD, and IOL position; IOL position with the ASD, ESD, and PSD; and refractive prediction error with the difference between the predicted postoperative anterior chamber depth (ACD) of the SRK/T formula and the IOL position, ASD, ESD, and PSD (each depth minus the predicted postoperative ACD of the SRK/T formula). RESULTS: The LT was significantly correlated with the ASD (r = -0.65) and PSD (r = 0.41), whereas it was not correlated with the ESD or IOL position. The IOL position was significantly correlated with the ASD (r = 0.67), ESD (r = 0.72), and PSD (r = 0.74). The refractive prediction error was significantly correlated with the difference between the predicted postoperative ACD of the SRK/T formula and the IOL position (r = 0.65), ASD (r = 0.46), ESD (r = 0.54), and PSD (r = 0.58). CONCLUSIONS: The ESD and PSD obtained using AS-OCT were highly correlated with the IOL position and significantly correlated with the refractive prediction error. These findings suggest that the ESD and PSD may enhance the accuracy of actual IOL position prediction.

Predictability of the vault after posterior chamber phakic intraocular lens implantation using anterior segment optical coherence tomography.

PURPOSE: To determine whether vault measurements after placement of a hole implantable collamer lens (hole ICL) (KS-AquaPORT) can be predicted by angle-to-angle (ATA) and white-to-white (WTW) measurements obtained with anterior segment optical coherence tomography (AS-OCT). SETTING: Sanno Hospital, Tokyo, Japan. DESIGN: Retrospective case series. METHODS: Eyes were observed for 3 months after hole ICL implantation for myopia or myopic astigmatism. Central vault, ATA, and WTW measurements were obtained before and after surgery using the swept-source AS-OCT CASIA2 system. RESULTS: The study included 44 eyes (23 patients). The mean patient age and preoperative spherical equivalent, ATA, and WTW values were 36.2 years ± 8.8 (SD), -6.23 ± 3.41 diopters (D), 12.03 ± 0.40 mm, and 11.72 ± 0.40 mm, respectively. The safety index and efficacy index 3 months postoperatively were 1.13 ± 0.21 and 0.91 ± 0.30, respectively. Regarding predictability, 93.2% of eyes were within ±0.50 D of the attempted correction and all eyes were within ±1.00 D. The reproducibility coefficients for the ATA distance and WTW distance were 0.998 and 0.960, respectively. The mean postoperative central vault was 491.6 ± 189.5 µm. There was a significant correlation between postoperative vault and the ICL size and ATA distance (Spearman rank correlation coefficient r = 0.59, P < .001) but not between the ICL size and WTW distance (r = 0.27, P = .08). CONCLUSION: The ATA measurements had higher reproducibility than the WTW measurements on AS-OCT, making it is a more important predictor of postoperative vault.

Prediction of pupil size under binocular open-view settings using the new CASIA2 device.

PURPOSE: Pupillometry should be performed under conditions as close to natural viewing as possible. The present study aimed to determine whether pupil size in binocular open-view settings can be predicted based on pupil size measured using the CASIA2 device. METHODS: The present study included 61 participants (25 men and 36 women; mean age, 49 ± 15 years; age range, 22-69 years) with no history of ophthalmic disease other than refractive errors and cataract. We measured pupil size using the new CASIA2 device and a binocular open-view digital pupillometer (FP-10000II, TMI Co., Ltd., Saitama). Intra-class and inter-class reliabilities were evaluated by measuring pupil times three times with each device (two independent examiners) in 21 of the 61 participants. Reproducibility was analyzed using intra-class and inter-class correlation coefficients (ICCs). Regression formulae for calculating FP10000II pupil size based on CASIA2 pupil size were developed via simple linear regression analyses. RESULTS: Both devices exhibited high ICC values (> 0.80). The regression formulae for calculating the FP10000II pupil size for the distant and near views based on CASIA2 pupil size were y = 0.5702x + 0.4611 (determination coefficient, 0.67) and y = 0.502x + 0.445 (determination coefficient, 0.64), respectively. CONCLUSIONS: Pupil size under binocular open-view settings can be predicted based on simultaneous measurement of pupil size during evaluation of the anterior segment using the CASIA2 device. The calculated pupil size may represent a useful index for determining the most appropriate treatment strategy in candidates for cataract and refractive surgery.

Vault Changes Caused by Light-Induced Pupil Constriction and Accommodation in Eyes With an Implantable Collamer Lens.

PURPOSE: An appropriate vault after implantation of a posterior chamber phakic intraocular lens with a central hole (ICL KS-AP) is important for successful long-term outcomes. In the present study, we used anterior segment optical coherence tomography (AS-OCT) to examine dynamic pupil and vault changes under photopic and scotopic conditions and during accommodation in eyes with ICL KS-AP. METHODS: This retrospective study included patients at an outpatient ophthalmology clinic who underwent ICL KS-AP implantation >1 month before enrollment. All patients underwent dynamic AS-OCT imaging under photopic and scotopic conditions. Patients aged <40 years also underwent imaging in the accommodative and nonaccommodative states. Primary outcome measures were the pupil size and vault at the maximum and minimum pupil sizes. RESULTS: This study included 91 eyes of 47 patients (35.5 ± 8.6 years, 21 men). Accommodation was examined in 51 eyes of 26 patients (28.9 ± 5.0 years, 10 men) younger than 40 years. The pupil size was significantly smaller under photopic conditions (3.64 ± 0.77 mm) than under scotopic conditions (4.91 ± 0.75 mm, P < 0.001) and during accommodation (3.88 ± 0.64 vs. 4.10 ± 0.61 mm, P < 0.001). Vault was also significantly lower under photopic conditions (476.1 ± 219.6 µm) than under scotopic conditions (521.1 ± 220.4 µm, P < 0.001) and during accommodation (454.8 ± 224.9 vs. 481.6 ± 219.1 µm, P < 0.001). CONCLUSIONS: Vault can be significantly lowered by light-induced pupil constriction and accommodation in eyes with ICL KS-AP.

Prospective Randomized Multicenter Comparison of the Clinical Outcomes of V4c and V5 Implantable Collamer Lenses: A Contralateral Eye Study.

PURPOSE: To compare the visual and refractive outcomes and night vision performance questionnaire results between V4c and V5 implantable Collamer lenses in a prospective, randomized, multicenter study. SETTINGS: Four refractive surgery centers. DESIGN: Prospective randomized multicenter single-masked comparative study. METHODS: Twenty-three patients were enrolled in this study. A conventional V4c model (EVO Visian ICL) was implanted in one eye, and a V5 model (EVO+ Visian ICL), which has a larger optic diameter than the V4c model, was implanted in the contralateral eye. The uncorrected distance visual acuity (UDVA) and corrected distance visual acuity (CDVA) were evaluated before and 6 months after surgery. At 6 months after surgery, a questionnaire on night vision disturbances was administered. The efficacy, safety, and predictability of the two implanted ICL models were compared. RESULTS: There were no significant differences in the postoperative UDVA and CDVA between the two ICL models. The mean efficacy indexes for the V4c and V5 lenses were 1.16 ± 0.22 and 1.03 ± 0.23, respectively. The mean safety indexes of the V4c and V5 lenses were 1.21 ± 0.20 and 1.19 ± 0.20, respectively. The night vision performance questionnaire revealed that 7 patients (37%) noticed a difference in visual performance between the eyes, and all of them reported that they could see better at night with the V5-implanted eye compared with the V4c-implanted eye. CONCLUSION: The V4c and V5 ICL models achieved similar visual and refractive outcomes, whereas the V5 model showed a possible advantage in reducing night vision disturbances.