Factors affecting vaulting after implantable collamer lens implantation

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.

Long-Term Vault Changes in Different Levels and Factors Affecting Vault Change After Implantation of Implantable Collamer Lens with a Central Hole

INTRODUCTION

This study evaluated vault changes in eyes implanted with an implantable Collamer lens (ICL) with a central hole (ICL V4c) for myopia and astigmatism correction as well as factors related to vault changes over time.

METHODS

This retrospective study enrolled 169 myopic eyes from 169 patients (137 women and 32 men) who underwent ICL V4c implantation to correct myopia and astigmatism. Vault values were measured quantitatively using a rotating Scheimpflug camera. Each patient underwent at least four postoperative follow-up visits at 1 month, 6 months, 1 year, and more than 2 years. We compared postoperative values between groups and identified factors affecting vault changes over time.

RESULTS

The mean vaults at 1 month (baseline), 6 months, 1 year, and the last follow-up time following ICL implantation were 540.83 ± 186.13, 520.00 ± 196.08, 503.79 ± 198.30, and 471.42 ± 211.35 μm, respectively. Eyes with baseline vaults of 250-750 and ≥ 750 μm exhibited a trend of vault decrease over time, and the differences were statistically significant (P < 0.05) at 6 months and 1 year postoperatively, respectively. The variables relevant to the value of vault decrease between baseline and last follow-up time were anterior chamber depth (ACD) and ICL power (adjusted R² = 0.121, P < 0.001).

CONCLUSIONS

We found a trend of decreased mean objective vault values over time, which was more obvious in eyes with higher baseline vault values. The vault value of the ICL decreased more in eyes with shallower ACDs, higher ICL power, or both. Moreover, the decrease in vault values became statistically significant earlier in eyes with higher baseline vaults or shallower ACDs.

Analysis of perioperative problems related to intraocular Implantable Collamer Lens (ICL) implantation

PURPOSE

To introduce a modified procedure of ICL implantation, to summarize the perioperative problems and their corresponding treatment after myopia correction with Implantable Collamer Lens (ICL), and to compare the difference of complications between the no-hole ICL and hole ICL.

METHODS

We searched all articles on ICL-related perioperative problems and their corresponding treatment in Scopus, Embase, PubMed and Web of Science databases for the last 22 years.

RESULTS

ICL implantation is safe, effective, stable and predictable in the correction of myopia, hyperopia and astigmatism, but can also cause a series of perioperative problems, including intraoperative and postoperative complications.

CONCLUSION

There are many kinds of complications related to ICL, but the common intraoperative and postoperative complications mainly include abnormality of arch height, abnormal position of ICL, loss of corneal endothelial cells and corneal decompensation, high intraocular pressure and secondary glaucoma, cataract and night vision symptoms. Compared with ICL without central pore, the incidence of complications such as loss of corneal endothelial cells and corneal decompensation, high intraocular pressure and secondary glaucoma and cataract was relatively lower in central hole ICL, while postoperative complications such as night vision symptoms were obvious.

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.

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.].

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.

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.

Prediction of the trabecular iris angle after posterior chamber phakic intraocular lens implantation

PURPOSE

To create an equation for predicting the trabecular iris angle (TIA) and to verify its accuracy after implantable collamer lens (ICL) implantation.

SETTING

Nagoya Eye Clinic, Nagoya, Japan.

DESIGN

Retrospective evaluation of a screening approach.

METHODS

The subjects included 174 eyes (174 patients) that underwent ICL implantation. Patients were randomly assigned to the prediction equation group (116 eyes) or verification group (58 eyes). Anterior segment optical coherence tomography (AS-OCT; CASIA2 TOMEY) was performed before and 3 months after ICL surgery. For the prediction group, a prediction equation was created with the preoperative AS-OCT parameters and ICL size as independent variables and the postoperative anterior chamber depth (ACD) as dependent variables. Then, by applying the predicted post-ACD and preoperative AS-OCT parameters as independent variables and TIA after ICL surgery as the dependent variable, a prediction equation was created to predict the postoperative TIA (post-TIA) after ICL surgery. Each prediction equation was created using stepwise multiple regression analysis, and its accuracy was verified by a Bland-Altman plot in the verification group.

RESULTS

The explanatory variables (standardized partial regression coefficient) selected in the post-TIA prediction equation were post-ACD (0.629), TIA750 (0.563), iris curvature (0.353), pupil diameter (-0.281), iris area (-0.249), and trabecular iris space area 250 (-0.171) (R2 = 0.646). There were no clinically significant systematic errors between measured and predictive post-TIA values in the verification group. The average absolute prediction error was 3.43° ± 2.22°.

CONCLUSIONS

Post-TIA can be accurately predicted from the predicted post-ACD and other preoperative AS-OCT parameters.

Optimization of implantable collamer lens sizing based on swept-source anterior segment optical coherence tomography

PURPOSE

To optimize the implantable collamer lens (ICL) sizing method using anterior segment optical coherence tomography (AS-OCT).

SETTING

Nagoya Eye Clinic, Nagoya, Japan.

DESIGN

Interventional case series.

METHODS

A stepwise multiple regression analysis was performed using the optimal ICL size as a dependent variable and preoperative AS-OCT parameters as explanatory variables for 81 eyes of 41 patients, and the NK-formula version 2 (NK-formula V2) was obtained. Thereafter, 68 eyes of 42 patients were implanted with the ICLs selected as closest to the optimal ICL size calculated by the NK-formula V2. At 3 months postoperatively, the achieved vault was measured by AS-OCT to evaluate the optimization of the sizing method.

RESULTS

The anterior chamber width (ACW) and crystalline lens rise were selected as significant parameters for the regression model (R = 0.61, P < .001), as with the previous NK-formula. Of the 68 eyes, 36 patients/62 eyes (91.2%), 5 patients/5 eyes (7.3%), and 1 patient/1 eye (1.5%) were in the moderate, high, and low vault categories, respectively. In the 68 eyes, the vault showed no correlation with the optimal ICL size (R = 0.0185, P = .269), whereas the vault showed a negative correlation with the optimal ICL size in both the 12.6 mm ICL subgroup (R = -0.409, P = .0088) and the 13.2 mm ICL subgroup (R = -0.818, P = .0013).

CONCLUSIONS

This optimization approach showed excellent ability to select an appropriate ICL to be implanted regardless of the value of other ocular parameters and age, except ACW.

Vault changes after cyclopentolate instillation in eyes with posterior chamber phakic intraocular lens

Posterior chamber phakic intraocular lens (pIOL) implantation is a common option for correcting moderate-to-high ocular refractive defects. Because this pIOL is implanted on ciliary sulcus, the distance between the back surface of the pIOL and the anterior surface of the crystalline lens, that it is known as vault, should be measured in different conditions to ensure the technique's safety. Cyclopentolate is a drug that dilates the pupil and relaxes accommodation (cycloplegia). It is often used for different ocular examinations and for other medical purposes. However, there is no evidence of the effect of this drug on vault. This study quantified central vault changes associated with cyclopentolate instillation. We measured the vault under normal conditions (pre-cycloplegic instillation) and after instilling cyclopentolate on 39 eyes of 39 patients with implanted pIOL. Our results suggest that cyclopentolate instillation may induce changes to vault in eyes with implanted pIOL. These changes seem safe and are mainly associated with vault under normal conditions, but also with anterior chamber depth, pupillary diameter and pIOL size.

Comparative study of anterior segment measurements using 3 different instruments in myopic patients after ICL implantation

Background

To compare and correlate anterior segment measurements of myopic eyes implanted with Implantable Collamer lens (ICL V4c) by using anterior segment optical coherence tomography (AS-OCT), Pentacam and ultrasound biomicroscopy (UBM).

Methods

Anterior chamber depth (ACD), distance between corneal endothelium and anterior surface of ICL(C-ICL) and central vault were measured in 82 phakic myopic eyes of 82 patients who underwent ICL surgery, by using AS-OCT, Pentacam and UBM consecutively at 3 months follow up. The correlation and agreement of instruments were accessed by using Intraclass correlation coefficient (ICC) and the Bland-Altman plot.

Results

AS-OCT showed higher ACD, C -ICL and central vault measurements than both of Pentacam and UBM (P < 0.001), while Pentacam showed lower measurements than UBM (P < 0.05). The Pearson correlation coefficient (r) was 0.91 to 0.96, and ICC was 0.95 to 0.98 for all measurements between difference devices (all P < 0.001). The 95% limits of agreement of ACD, C-ICL, vault measurements were 0.13 to 0.38 mm, − 0.07 to 0.27 mm, 0.08 to 0.34 mm between AS-OCT and Pentacam, − 0.03 to 0.33 mm, − 0.16 to 0.31 mm, − 0.10 to 0.26 mm between AS-OCT and UBM, and − 0.29 to 0.07 mm, − 0.25 to 0.20 mm, − 0.31 to 0.05 mm between Pentacam and UBM, respectively.

Conclusions

AS-OCT demonstrated significantly higher value, while Pentacam demonstrated significantly lower value than UBM for ACD, C-ICL and central vault measurements in myopic eyes after ICL surgery. Measurements with these instruments were highly correlated, but could not replace each other especially for vault. This study provided valuable information about how to judge the results of anterior segment parameters of eyes implanted with ICL V4c from different devices.

Trial registration

Registration number: ChiCTR-OOC-16008987. Retrospectively registered: 08 August 2016.

Posterior chamber phakic intraocular lens for the correction of high myopic anisometropic amblyopia in adults

This study aims to evaluate the clinical results of posterior chamber implantable collamer lens (ICL) implantation in adults with high myopic anisometropic amblyopia. Thirteen patients aged 27.04±7.24y (range 19.2 to 42.5) were studied. ICL implantation was performed in 13 amblyopic eyes. The mean myopic anisometropia was significantly dropped from -10.70±3.02 D preoperatively to +0.09±1.67 D at 1mo postoperatively. The logMAR CDVA at 3d, 1, 3 and mean 9mo postoperatively improved by a mean of 1.69, 2.50, 3.01 and 3.00 lines and gained more than 2 lines accounted for 23.08% (3 eyes), 41.67% (5 eyes), 63.63% (7 eyes) and 55.56% (5 eyes), respectively. The contrast sensitivity of amblyopic eyes was significantly increased after surgery. Four patients partially recovered near stereopsis (400″ to 100″). There was no severe complications were observed. ICL implantation alone can improve vision, contrast sensitivity, and partial restoration of binocular vision in adult patients with high myopic anisometropia.

Implantable collamer lens surgery in patients with primary iris and/or ciliary body cysts

BACKGROUND

The prevalence of primary iris and/or ciliary body cysts is common in myopia, though asymptomatic in nearly all cases. It's a very valuable thing to study the clinical safety and reliability of implantable collamer lens (ICL) surgery in patients with primary iris and/or ciliary body cysts.

METHODS

A total of 108 patients (201 eyes) were included in this retrospective study. All eyes had been implanted with V4c implantable collamer lens (ICLV4c). According to the eyes with or without primary iris and/or ciliary body cysts, all eyes were divided into two groups. We observed preoperative and postoperative uncorrected distance visual acuity (UDVA), corrected distance visual acuity)(CDVA), intra-ocular pressure(IOP), anterior chamber volume(ACV), anterior chamber depth(ACD), trabecular-iris angle (TIA), angle opening distance at 500 μm (AOD500),vertical central distance between the corneal endothelium and the front surface of ICL(CE-ICL), and the central vault. The follow-up periods covered 12 months.

RESULTS

Among all the 201 eyes, primary iris and/or ciliary body cysts were detected in 54 eyes (26.87%),but the prevalence was account to 36.11%(18males,21females).There were 30 eyes (55.56%) with unilateral single cyst, 12 eyes (22.22%) with unilateral double cysts, 12 eyes (22.22%) eyes with unilateral multiple and/or multi-quadrants cysts, the mean size of cysts was (0.714 ± 0.149)mm(range from 0.510 to 1.075 mm).30.4% of the cysts were located at iridociliary sulcus, 65.5% in pars plicata, and 4.1% in midzonal iris, which showed a characteristic distribution pattern, with cysts found predominantly in the inferior and temporal quadrants.The postoperative size and the number of cysts showed nearly no changes. The postoperative ACV, AOD500 and TIA showed a statistical reduction in both two groups (P < 0.05), but with no statistical significant between the two groups (P > 0.05), the parameters of postoperative IOP,CE-ICL and central vault also showed the same results as which. We did not observe serious complication and IOP elevating in the whole follow-up periods.

CONCLUSION

Primary iris and/or ciliary body cysts are not absolutely contraindication for ICL surgery. For some single cyst smaller than 1.075 mm or single quadrant cysts located at ciliary body are rare to lead some serious complications. But, for some multiple cysts, especially multi-quadrants cysts located at iridociliary sulcus, we still should remain cautions.

Two-Year Outcomes of Visian Implantable Collamer Lens with a Central Hole for Correcting High Myopia

Purpose

To investigate two-year outcomes of Visian Implantable Collamer Lens with a central hole (ICL V4c) implantation for correcting high myopia.

Methods

Sixty-one eyes of 32 patients went through ICL V4c implantation. Safety, efficacy, predictability, and intraocular pressure were evaluated 2 years postoperatively. Anterior chamber volume (ACV), anterior chamber depth (ACD), anterior chamber angle width (ACAW), and vault were measured using a Scheimpflug tomography imaging system.

Results

At 2 years, the spherical equivalent refraction decreased from preoperative −14.62 ± 4.29 D to −0.90 ± 0.95 D, with 79% of the eyes within ±0.50 D and 98% within ±1.00 D of the intended correction. The efficacy index was 1.03 ± 0.23, and the safety index was 1.24 ± 0.26. Corrected distance visual acuity (CDVA) remained unchanged in 23% of the eyes, 75% gained one or more lines of CDVA, and 2% lost one line. The ACV, ACD, and ACAW, respectively, decreased from 193.28 ± 29.15 mm³, 3.15 ± 0.23 mm, and 36.51 ± 6.54 degree to 112.48 ± 17.01 mm³, 2.99 ± 0.23 mm, and 22.54 ± 5.27 degree (p=0.0008, 0.008, and  0.0003, resp.). Intraocular pressure was 15.39 ± 2.88 mmHg before surgery and was 15.86 ± 4.11 mmHg at 2 years (p=0.11).

Conclusion

Implantation of ICL V4c is a safe, effective, and predictable procedure for correcting high myopia. Reduction of anterior chamber space after surgery did not induce intraocular pressure increase during the 2-year follow-up.

Analysis of intraocular positions of posterior implantable collamer lens by full-scale ultrasound biomicroscopy

Background

To analyze the positions of intraocular posterior Implantable Collamer Lens (ICL) and its possible relationship with vault.

Methods

This cross-sectional study included 72 patients with high myopia (134 eyes) who were followed up after phakic intraocular lens implantation. The postoperative time ranged from 1 week to 7 years. We obtained the images of ICL by using Compact Touch STS UBM and observed the position of ICL in posterior chamber and ciliary sulcus. The horizontal lines vault was measured and recorded.

Results

There were various positions in the posterior chamber as observed by full-scale ultrasound biomicroscopy and the haptics were inserted at different positions. -Eight seven eyes (64.9%) that obtained ideal vault, 29 eyes (21.6%) had insufficient vaults and 18 eyes (13.4%) had excessive vault. The vault with various positions of haptics was in ideal range (250 μm–750 μm) almost in each group. Three eyes in this study with haptics on the top of ciliary sulcus obtained excessive vault (mean vault, 850.00 ± 70.71 μm) and one eye appeared one side haptics pushing forward the iris. Among five eyes (3.7%) with iridociliary body cysts, three eyes (60%) obtained ideal vault. One eye (0.7%) with ICL decentralization after implantation surgery had an ideal vault, but the patient had serious glare.

Conclusions

Though ICL in the posterior chamber had different positions and the haptics in most cases were not in the ciliary sulcus, the postoperative vault was almost in the ideal range.

Iridociliary cysts do not impact on posterior phakic intraocular lens implantation for high myopia correction: A prospective cohort study in 1569 eyes

Purpose

To investigate the clinical characters and effect of iridociliary cysts among patients who had undergone posterior phakic intraocular lens implantation.

Methods

A total 1569 eyes of 866 high myopia patients, who underwent phakic intraocular lens implantation from 1 September 2011 to 31 August 2016, was included in this prospective cohort study. These patients were followed up for more than 12 months postoperatively.

Results

During the study period, 218 eyes (14%) of 154 patients were diagnosed with iridociliary cysts by ultrasound biomicroscopy. There were 74.3% patients with unilateral cysts and the cysts tended to have occurred in patients ages 20 to 30 years old (22%). The location of the cysts varied with temporal position as the most (50%) and superior position as the least (9.6%). After 1 week postoperative follow-up, there were no significant differences in clinical outcomes between the cysts group and no cysts group, but the proportion of 20/20 or better uncorrected visual acuity (UCVA), best corrected visual acuity (BCVA), and the 2 types of vector astigmatism. Intraocular pressure (IOP), refraction, and vault remained stable at different time points of the follow-up period, while vault of cysts patients tend to be lower than patients without cysts at more than 12 months.

Conclusions

Iridociliary cysts were more common than estimated and it had no impact on Phakic Intraocular Lens implantation because there was no clue to show significantly difference on postoperative clinical outcomes between the patients with and without iridociliary cysts in this study.

Anterior segment optical coherence tomography angle and vault analysis after toric and non-toric implantable collamer lens V4c implantation in patients with high myopia

OBJECTIVE

To assess anterior segment changes, including iridocorneal angle and vault, after toric and non-toric implantable collamer lens (ICL) V4c (STAAR Surgical AG) implantation under different lighting conditions.

METHODS

Longitudinal, prospective, case series. Patients with high myopia (>6 dioptres) underwent toric and non-toric ICL V4c implantation. Optical coherence tomography measurements were taken under different lighting conditions preoperatively and at 1 week and 1, 6 and 12 months of follow-up.

RESULTS

Seventy-six eyes of 42 patients underwent ICL V4c implantation. Mean age was 27.4 years (±5.14 years, range 20 to 39 years). The average iridocorneal angle showed a statistically significant decrease (p<0.05) in all mesopic, scotopic and photopic conditions after 1 week of surgery compared with the preoperative measurements; in mesopic conditions, it decreased 14.1°, in photopic conditions 14.8° and scotopic conditions 13.2°. The angle measurement had a statistically significant change only in mesopic conditions (p=0.01) over the 1-year follow-up. The average vault under mesopic conditions was 0.661±0.21 mm at week 1. The vault measurement change was statistically significant over the 1-year follow-up in mesopic conditions (p=0.01). Refractive results showed a significant improvement in both uncorrected and corrected distance visual acuity (p<0.001).

CONCLUSION

There is a significant reduction in the iridocorneal angle after ICL V4c implantation. Furthermore, there is a change under mesopic conditions in both the iridocorneal angle and vault during long-term follow-up.

Phakic posterior chamber intraocular lens for unilateral high myopic amblyopia in Chinese pediatric patients

AIM

To assess the outcomes of posterior chamber implantable collamer lens (ICL) implantation in Chinese pediatric patients with unilateral high myopic amblyopia.

METHODS

Eleven eyes of 11 amblyopic patients aged 11.02±3.34y underwent ICL (model V4, Staar Surgical Inc.) implantation to treat unilateral anisometropia were studied. Visual acuity, cycloplegic refraction, contrast sensitivity, stereopsis, intraocular pressure (IOP), vaulting, corneal endothelial cell count and complications were evaluated. Patients completed follow-up at 3d, 1, 3mo and the last follow-up time (mean 8.18±2.82mo) after surgery.

RESULTS

The mean myopic anisometropia was -13.70±3.25 D preoperatively and +0.69±2.63 D at 8mo postoperatively. The logMAR corrected distance visual acuity (CDVA) of the amblyopic eye was 1.51±0.72 preoperatively and 0.75±0.40 at 8mo postoperatively. The logMAR CDVA at 3d, 1, 3 and 8mo postoperatively improved by a mean of 0.64, 1.55, 1.82 and 2.64 lines and gained more than 2 lines accounted for 18%, 45%, 45%, 64%, respectively. The contrast sensitivity of 0.5, 1 and 2 cpd in amblyopic eyes was significantly increased after surgery. No patient had near stereopsis recovery. The vaulting at 3 and 8mo was significantly lower than that at 1mo postoperatively. No other intraoperative or postoperative complications were observed, except an acute pupillary block glaucoma happened in a patient at two weeks postoperatively.

CONCLUSION

This short-term results indicate that ICL implantation can be a promising alternative therapy for high myopic anisometropic amblyopia in pediatric patients who have failed with conventional treatments and not suitable to corneal refraction surgery.

In Vivo Positional Analysis of Implantable Collamer Lens Using Ultrasound Biomicroscopy

Purpose. To evaluate the anterior segment, the anatomical position of the implantable collamer lenses (ICL), and its relationship to adjacent ocular structures using Ultrasound Biomicroscopy (UBM). Methods. In a prospective study, 142 myopic eyes of 93 patients implanted with Visian ICL were subjected to UBM examination between March 2010 and January 2015. The relative position of ICL to the adjacent structure and the overall iris configuration were evaluated. The machine calibers were used to measure the minimum central distance between the ICL and anterior lens capsule (vault) and the vertical central distance between the corneal endothelium and the ICL (E-ICL). Results. The mean ICL vault was 376 ± 105 μm. The mean E-ICL was 2826 ± 331 μm. Contact between ICL and the posterior epithelium of the iris was present in all eyes. The overall iris configuration was flat in 89 eyes. Central anterior convexity was present in 41 eyes and mild peripheral iris bombe in 12 eyes. The haptics could be imaged in the ciliary sulcus in 112 eyes and at least one haptic resting on the lens periphery and zonules in 30 eyes. Conclusion. UBM can provide valuable anatomical information that allows detailed postoperative in vivo assessment of ICL.

Comparison of early changes in and factors affecting vault following posterior chamber phakic Implantable Collamer Lens implantation without and with a central hole (ICL V4 and ICL V4c)

Background

To objectively compare the early changes in vault over time following implantation of an Implantable Collamer Lens without (ICL V4) and with (ICL V4c) a central hole and the respective factors affecting vault change in moderate to high myopia.

Methods

This prospective study comprised of 38 eyes of 38 patients implanted with ICL V4 and 39 eyes of 39 patients implanted with ICL V4c intraocular lenses. We quantitatively assessed the postoperative values of vault and pupil size at 1 day, 1 week, and 1 month following implantation using a rotating Scheimpflug camera (Pentacam). We compared these postoperative values within and between the two groups and identified the factors affecting vault change.

Results

The mean vaults at 1 day, 1 week, and 1 month following ICL V4 implantation were 303.68 ± 185.11, 517.89 ± 160.07 and 521.32 ± 155.72 μm respectively, and those following ICL V4c were 316.67 ± 186.89, 495.13 ± 180.84 and 510.77 ± 175.51 μm, respectively. There was a significant difference in vault between 1 day and 1 week postoperatively. There was a significant association between the vault change and the pupil size change in both groups from 1 day to 1 month postoperatively (Pearman correlation coefficient; ICL V4: r = 0.585, P = 0.001; ICL V4c: r = 0.588, P <0.001). The vault value 1 month after implantation of ICL V4 and ICL V4c was associated with the preoperative anterior chamber depth, horizontal corneal diameter, horizontal and vertical sulcus-to-sulcus.

Conclusions

Pupil movement is a critical factor in vault change, with increasing vault observed postoperatively from 1 day to 1 week associated with the declining effects of pharmacological miosis and increasing pupil size. The anterior chamber depth, horizontal corneal diameter, horizontal and vertical sulcus-to-sulcus show some correlation with vault.

Electronic supplementary material

The online version of this article (doi:10.1186/s12886-016-0336-8) contains supplementary material, which is available to authorized users.

Comparison of anterior section parameters using anterior segment optical coherence tomography and ultrasound biomicroscopy in myopic patients after ICL implantation

AIM

To compare the agreement of anterior chamber depth (ACD) and central vault measurements obtained by anterior segment optical coherence tomography (AS-OCT) and ultrasound biomicroscopy (UBM) of post surgical high myopic eyes with posterior chamber phakic intraocular lens (Visian ICL; STAAR Surgical) implantation.

METHODS

Fifty-two phakic eyes of 28 high myopic patients who underwent implantable Collamer lens (ICL) surgery for the correction of high myopia were studied. The postoperative ACD, the distance between the corneal endothelium and the anterior surface of ICL (cornea-ICL) and the central vault were measured with the AS-OCT system and the UBM system. Intraclass correlation coefficient (ICC) and the Bland-Altman plot were used to evaluate the repeatability and agreement of two devices.

RESULTS

The mean ACD, cornea-ICL and central vault in the 52 phakic eyes after ICL surgery was 3.19±0.28 mm, 2.47±0.28 mm, 0.50±0.19 mm by AS-OCT and 3.13±0.25 mm, 2.49±0.25 mm, 0.44±0.19 mm by UBM, respectively. Pairwise comparison of ACD and central vault measurements showed significant differences between AS-OCT and UBM (P<0.05). However, no statistically significant difference was found between these imaging techniques in cornea-ICL (P>0.05). The Pearson correlation coefficient (r) between AS-OCT and UBM measurements for ACD, cornea-ICL and vault was 0.88, 0.80 and 0.89, respectively (P<0.001). The ICC was 0.89-0.94 for the measurements of AS-OCT and UBM. Bland-Altman analysis showed the 95% limits of agreement of ACD, cornea-ICL, central vault measurements between these two devices were -0.20 to 0.32 mm, -0.36 to 0.32 mm and -0.12 to 0.24 mm, respectively.

CONCLUSION

Central ACD and vault measurements using AS-OCT demonstrated a slight significantly higher value than using UBM in phakic eyes after ICL surgery. These two devices should not be used interchangeably for measurements of central ACD and vault in patients after phakic intraocular lens implantation.

Implantable collamer lens versus iris-fixed phakic intraocular lens implantation to correct myopia: a meta-analysis

This study is a meta-analysis comparing the efficacy, predictability, and safety of correcting myopia via implantation of two types of phakic intraocular lens (PIOLs): the implantable collamer lens (ICL) and iris-fixed PIOL. The Cochrane library, Pubmed, and EMBASE were searched. Study selection, data exclusion, and quality assessment were performed by two independent observers. The pooled relative risk (RR), pooled standardized mean difference (SMD), and their 95% confidence intervals (CIs) were used to compare lenses. Seven studies, involving 511 eyes, were included. The pooled SMD in postoperative uncorrected distance visual acuity (UDVA) comparing ICLs to iris-fixed PIOLs was −0.22 (95% CI, −0.58 to 0.13; P = .22). The pooled RR values of UDVA of 20/20 or better and of 20/40 or better comparing ICLs to iris-fixed PIOLs were 1.15 (95% CI, 0.89 to 1.47; P = .29) and 1.01 (95% CI, 0.95 to 1.08; P = .75), respectively. The pooled RR of loss of best spectacle-corrected visual acuity (BSCVA) and gain in BSCVA comparing ICLs to iris-fixed PIOLs were 1.20 (95% CI, 0.24 to 6.00; P = .82) and 1.14 (95% CI, 0.89 to 1.48; P = .31), respectively. The pooled RR comparing ICLs to iris-fixed PIOLs was 0.78 (95% CI, 0.29 to 2.12; P = .63) for all reported complications and 2.80 (95% CI, 1.04 to 7.52; P = .04) for severe complications. The pooled RR of achieving a result within ±0.5 D (diopter) of the intended target comparing ICLs to iris-fixed PIOLs was 1.35 (95% CI, 1.04 to 1.77; P = .03). Overall, there is no significant difference in efficacy between the two types of PIOLs or in safety, except that the ICL is associated with a greater incidence of severe complications, especially anterior subcapsular cataract, primarily in the Version 2 and Version 3 groups. However, ICL has better predictability.

Central vault after phakic intraocular lens implantation: correlation with anterior chamber depth, white-to-white distance, spherical equivalent, and patient age

PURPOSE

To compare the central postoperative vault of a phakic intraocular lens (pIOL) to correct myopia, myopic astigmatism, and hyperopia and identify ocular and lens parameters that might predict the vault amount.

SETTING

Fernández-Vega Ophthalmological Institute, Oviedo, Spain.

DESIGN

Cohort study.

METHODS

Three months after implantation of Implantable Collamer Lens pIOLs to correct myopia, hyperopia, and myopic astigmatism, central vault was measured using optical coherence tomography. Patients were divided into groups according to the preoperative anterior chamber depth (ACD) to compare the effects of ACD, white-to-white (WTW) distance, and lens diameter on postoperative pIOL vault.

RESULTS

Hyperopic pIOLs had statistically significantly lower vault followed by myopic pIOLs and toric pIOLs, which had a higher mean value and narrower range (260 to 860 μm). Measured vaults had a positive correlation with preoperative ACD (r = .32, P<.001) and WTW (r = .29, P<.001) and a negative correlation with preoperative spherical equivalent (SE) (r = -0.21, P<.001) and patient age (r = -0.12, P=.025). Eyes with a vault of 250 μm or less had a shallower ACD than eyes with a vault between 250 μm and 750 μm (mean difference -0.11 mm; P=.012) and those with a vault greater than 750 μm (mean difference -0.25 mm; P<.001).

CONCLUSIONS

Central vaulting was lower in hyperopic eyes. Current nomograms for pIOL diameter selection based on ACD and WTW might yield ideal vault and may have to be adjusted for older patients, shallower ACD, lower WTW, and lower SE.