Meta-analysis and review: effectiveness, safety, and central port design of the intraocular collamer lens

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.

Long term efficacy and safety profiles following posterior chamber phakic intraocular lens implantation in eyes with ≥ 10-year follow-up

PURPOSE

Evaluate long-term efficacy, safety, predictability and stability of a posterior chamber phakic intraocular lens (Visian ICL) in eyes with ≥10-year follow-up.

SETTING

Instituto de Microcirugía Ocular, Barcelona, Spain.

DESIGN

Retrospective study.

METHODS

Eyes undergoing ICL implantation from 2008-2011 with ≥10-year follow-up were included. Variables analyzed were: preoperative, 1-month, 1-year, 5-years and last follow-up uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), manifest refraction, spherical equivalent (SE), endothelial cell count (ECC) and intraocular pressure (IOP). Descriptive statistics were performed and results reported following the Standard for Reporting Refractive Surgery Outcomes.

RESULTS

45 eyes (26 patients) were analyzed, mean follow-up 11.35 ± 1.30 years. Mean preoperative SE was -10.06 ± 3.40D and mean preoperative cylinder -1.55 ± 1.45D. At last follow-up, efficacy and safety indices were 0.79 and 1.12, respectively. In total, 32 (71%) eyes achieved an UDVA of ≥20/40. 22 (49%) eyes gained ≥1 line of CDVA, and 2 (4%) eyes lost ≥2 lines of CDVA. At final follow-up, 19 (42%) and 29 (64%) eyes were within ±0.50D and ±1.00D of attempted SE correction, respectively. 31 (69%) eyes had ≤1.00D of postoperative astigmatism and 29 (74%) eyes were within ±15° from the intended correction axis. At the last visit, a statistically significant myopic progression of -0.75 ± 1.20D was observed (p=0.01). ECC loss at last follow-up was 9.85 ± 11.35%. IOP remained stable. There were no intraoperative complications. 3 eyes (7%) developed cataract after 10 years.

CONCLUSIONS

Long-term results demonstrate that ICL is effective, predictable, stable and safe.

Comparison of Horizontal Corneal Diameter Measurements Using Orbscan IIz, OPD Scan III, and IOLMaster 700

PURPOSE

To compare three automated devices for measuring the horizontal corneal diameter (white to white [WTW]).

METHODS

In 65 eyes of 38 patients, the WTW distance was measured independently by three examiners using the following techniques: Orbscan IIz tomography system (Bausch & Lomb), IOLMaster 700 (Carl Zeiss Meditec), and OPD Scan III (NIDEK). We tested for systematic differences in measurements and estimated the limits of agreement (LoA) using linear mixed-effects models.

RESULTS

The mean WTW distance was 11.8±0.40 mm with Orbscan IIz, 12.1±0.5 mm with IOLMaster 700 and 12.0±0.4 mm with OPD Scan III. The mean difference between IOLMaster 700 and Orbscan IIz was 0.33 (95% CI, 0.28 to 0.38; P<0.001), between OPD Scan III and Orbscan IIz was 0.24 mm (95% CI, 0.21 to 0.28; P<0.001), and between IOL Master 700 and OPD Scan III was 0.09 (95% CI, 0.05 to 0.12; P<0.001). The 95% LoA for Orbscan IIz versus IOLMaster 700 was -0.69 to 0.03 mm, Orbscan IIz versus OPD Scan III was -0.52 to -0.03 mm, and OPD versus IOLMaster 700 was -0.39 to 0.22 mm.

CONCLUSIONS

The data suggest that these devices are not interchangeable for usual clinical practice. Adjustments based on mean differences were not enough to compensate for interinstrument discrepancy in WTW measurements.

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.].

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.

Effect of pupil size on posterior chamber phakic intraocular lens vault measurements

Purpose

The aim of this study was to measure the implantable collamer lens (ICL) vault changes with anterior segment optical coherence tomography (AS-OCT) after the implantation of the Visian posterior chamber phakic ICL with a central hole (V4c) in relation to the pupil size.

Methods

This retrospective observational pilot study included 32 eyes of 16 patients, who underwent V4c ICL implantation. ICL vault was measured with AS-OCT in undilated and fully dilate state of the pupil. Primary outcome measure was the change in the vault of V4c ICL at the maximum and minimum pupil size.

Results

Median (IQR) undilated and post-dilated vault measurement was 393.00 (335.50-493.50) microns and 421.00 (338.50-503.75) microns, respectively, which was not statistically significant (P = 0.44).

Conclusion

No statistically significant difference was observed between the undilated and post-dilated ICL vault measurements. Hence, the postoperative vault can be measured either in resting, undilated state or fully dilated state of the pupil and would be similar irrespective of the pupil size.

Visual and Refractive Outcomes With the Eyecryl Phakic Toric IOL Versus the Visian Toric Implantable Collamer Lens: Results of a 2-Year Prospective Comparative Study

PURPOSE

To compare the 2-year visual and refractive outcomes with the Eyecryl Phakic Toric IOL (EP TIOL) (Biotech Vision Care Pvt Ltd) and Visian Toric ICL (TICL) (STAAR Surgical) for correction of high myopic astigmatism.

METHODS

This prospective, interventional, non-randomized comparison study included eligible patients who underwent toric phakic IOL surgery in one or both eyes with either the EP TIOL or TICL for myopic astigmatism. Two years postoperatively, both lenses were compared for their safety, efficacy, stability, and patient satisfaction. Vector analysis of astigmatism was performed using the Alpins method with the ASSORT software (ASSORT Party Ltd).

RESULTS

A total of 50 eyes were included, of which 25 eyes received EP TIOL implantation and the remaining 25 received TICL implantation. Preoperative mean ± standard deviation of spherical equivalent (SE) and cylinder was -10.15 ± 4.04 and -2.08 ± 0.86 diopters (D) in the EP TIOL group and -10.21 ± 3.97 and -2.17 ± 0.95 D in the TICL group, respectively. At 2 years of follow-up, there was no significant difference between the mean uncorrected distance visual acuity, corrected distance visual acuity, spherical equivalent, and residual astigmatism between the two groups (P > .05 for all parameters). Ninety-two percent of eyes in the EP TIOL group and 88% of eyes in the TICL group were within ±0.50 D of refractive astigmatism. Vector analysis of astigmatism showed a comparable Correction Index of 0.98 in the EP TIOL group and 0.94 in the TICL group, signifying a mild undercorrection of 2% and 6%, respectively. Two eyes in the TICL group underwent exchange for high vault and one eye required realignment due to significant postoperative rotation.

CONCLUSIONS

At least for the first 2 years postoperatively, both toric phakic IOLs were safe and effective in managing high myopic astigmatism with comparable visual results and patient satisfaction. [J Refract Surg. 2021;37(1):7-15.].

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.

Clinical results of Visian implantable collamer lens implantation according to various sizes and implantation angles

PURPOSE

To investigate the clinical outcomes of Visian implantable collamer lens (ICL) implantation according to lens size and implantation angle.

SETTING

Onnuri Smile Eye Clinic, Seoul, Republic of Korea.

DESIGN

Retrospective case series.

METHODS

This study included 566 eyes of 283 patients treated with ICL implantation. Patients were divided into three groups: horizontally implanted same-sized ICL (group A), horizontally implanted different sized-ICL (group B: large ICL and small ICL) and same sized-ICL implanted with a different implantation angle (group C: horizontal and vertical).

RESULTS

At 12-month follow-up, the mean vault was 0.78 ± 17, 0.48 ± 0.13, 0.71 ± 0.18 and 0.44 ± 0.16 mm when large and small sized ICL was used in group B (p < 0.001), and when ICL was horizontally and vertically implanted in group C (p = 0.021), respectively. And the mean SE was -0.11 ± 0.30, -0.34 ± 0.42, -0.3 ± 0.56 and -0.64 ± 0.66 dioptres (D), when the large and the small sized ICL was used group B (p = 0.039), and when the ICL was horizontally and vertically implanted in group C (p = 0.036), respectively. No significant difference in UDVA, IOP and ECD between both eyes in groups B and C was observed. No statistical difference was found in the vault between both eyes for groups B and C.

CONCLUSIONS

The vault was significantly higher and the SE was significantly more hyperopic when a larger-sized ICL was used or the ICL was horizontally implanted compared to when the ICL was vertically implanted.

Occlusion of AquaPORT Flow in a Case of Toxic Anterior Segment Syndrome Following Implantable Collamer Lens Surgery Causing Severe Pupillary Block

PURPOSE

To present a case where following Implantable Collamer Lens (ICL) implantation the patient developed toxic anterior segment syndrome (TASS) with a subsequent pupillary block as a consequence of the occlusion of the AquaPORT (STAAR Surgical) flow hole.

METHODS

Case report and literature review.

RESULTS

A V4c toric ICL (STAAR Surgical) was implanted in the left eye of a 32-year-old woman. After 1 week, the lens was 15° off axis and uneventful lens alignment correction was performed. At postoperative day 1, an intraocular pressure (IOP) of 11 mm Hg and mild corneal edema were observed. At postoperative day 7, there was an uncorrected distance visual acuity of 20/800, an IOP of 44 mm Hg, diffuse corneal edema, and fibrin strands in the anterior chamber. TASS was diagnosed and topical steroids, cycloplegia, antiglaucoma drops, and oral acetazolamide were prescribed. At postoperative day 9, dispersed endothelial pigment with a fixed mid-dilated pupil were identified. Anterior segment optical coherence tomography showed strands of fibrin blocking the central ICL hole and angle closure. Pupillary block related to the fibrin occluding the AquaPORT hole consecutive to TASS was diagnosed. The patient underwent ICL removal, but had a persistent atonic, hyporeflexive pupil as a complication.

CONCLUSIONS

This case demonstrates that an AquaPORT hole may not be enough to prevent pupillary block in cases with postoperative intraocular inflammation, causing severe postoperative complications such as Urrets-Zavalia syndrome. Clinicians should consider this diagnosis in cases with corneal edema in the early postoperative period following AquaPORT ICL insertion. [J Refract Surg. 2020;36(12):856-859.].

Long-term assessment of crystalline lens transparency in eyes implanted with a central-hole phakic collamer lens developing low postoperative vault

PURPOSE

To assess long-term crystalline lens transparency in eyes implanted with phakic collamer intraocular lens (pIOL) with a central port and low postoperative vault for correction of myopia.

SETTING

Clinica Baviera, Madrid, Spain.

DESIGN

Retrospective cross-sectional single-center study.

METHODS

Using a noninvasive Fourier-domain swept-source anterior segment optical coherence tomography system, shifts in myopic and astigmatic myopic eyes implanted with a pIOL with vaulting lower than 100 μm in miosis and more than 4 years of follow-up were dynamically evaluated. Main outcome measures were pIOL dynamic vault (vault interval and vault range [VR]), crystalline lens density, and anterior subcapsular lens opacities. Crystalline lenses were examined under slitlamp microscopy, and lens density was evaluated using quantitative Scheimpflug images. Scheimpflug images were compared with those of a control group comprising eyes that were candidates for pIOL implantation.

RESULTS

The study population comprised 24 eyes from 16 patients previously implanted with a pIOL (5.82 ± 0.9 years) with central vault lower than 100 μm under photopically induced miosis. The mean vault value was 52 ± 19 µm under photopic light conditions and 113 ± 37 µm under scotopic conditions. The mean VR was 58 ± 24 μm. Anterior subcapsular lens opacities were found in only 1 eye (4.17%). The mean lens density was 7.94 ± 0.43, and no statistically significant differences were observed compared with the control group.

CONCLUSIONS

Long-term low vaulting in eyes implanted with a pIOL with a central port for correction of myopia was associated with a low risk for developing anterior crystalline lens opacities.

Use of neural networks to predict vault values after implantable collamer lens surgery

Background

Appropriate sizing of the implantable collamer lens (ICL) and accurate prediction of the vault are crucial prior to surgery. However, sometimes, the vault value is higher or lower than predicted, necessitating reoperation. The present study aimed to develop neural networks for improving predictions of vault values following ICL implantation based on preoperative biometric data.

Methods

This retrospective study included 137 eyes of 74 patients with ICLs. Linear regression and neural network analyses were used to examine the relationship between vault values at the 6-month follow-up and preoperative parameters (e.g., ICL characteristics and biometrics).

Results

Linear regression analysis revealed that vault values were correlated with five variables: ICL size, anterior chamber depth (ACD), angle-to-angle (ATA), white-to-white (WTW), and lens thickness (LT) (adjusted R² = 0.411). Inclusion of more input variables was associated with better performance in the neural network analysis. The degree of fit when all 11 variables were included in the neural network model was close to 1 (R² = 0.98). R² values for the quaternary neural network model enrolling four input variables (ICL size, ATA, ACD, and LT) reached 0.90.

Conclusions

A neural network equation including the ICL size and biometric parameters of the anterior segment (ATA, ACD, and LT) can be used to predict the postoperative vault, aiding in the selection of an appropriate ICL size and reducing the need for reoperation after surgery.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00417-021-05294-x.

Determining vault size in implantable collamer lenses: preoperative anatomy and lens parameters

PURPOSE

To determine patient preoperative anatomical features and the parameters of implantable collamer lenses (ICLs) relevant in explaining vault variability.

SETTING

Ophthalmology Clinic Vista Sánchez Trancón, Badajoz, Spain.

DESIGN

Retrospective case series.

METHODS

This study comprised 360 eyes of 360 patients implanted with myopic or toric ICLs. Pentacam imaging was used for assessing white-to-white (WTW) diameter, central keratometry, and central corneal thickness. Anterior-segment optical coherence tomography was used to measure the horizontal anterior chamber angle distance (ATA), internal anterior chamber (ACQ), crystalline lens rise (CLR), anterior chamber angle (ACA), and vault. The sample was divided according to the implanted lens size (12.6 mm, 13.2 mm, and 13.7 mm). Vault predictors were identified from the variables above using multivariate regression analysis.

RESULTS

The groups showed significant statistical differences for WTW, ATA, ACQ, ACA, and vault (P < .007 for all). In general, bigger lenses were implanted in eyes with larger transverse sizes (WTW and ATA) and deeper ACQ. Also, larger ICL diameters were associated with higher vaults. Multivariate regression analysis identified the lens size (13.2 mm as reference; 12.6 mm: β [standardized coefficients] = -0.33; 13.7 mm: β = 0.42), ATA (β = -0.42), and CLR (β = -0.25), ICL spherical equivalent (β = -0.22) and patient age (β = -0.12) as predictors of the vault size (adjusted-R = 0.34 P < .001).

CONCLUSIONS

The multivariate model explained 34% of vault variability. The predictors indicated the presence of different mechanisms regulating the vault. These involved the difference between the transverse size of the eye and the ICL, the crystalline lens protrusion, and the ICL properties, such as power and size.

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.

Biometric and ICL-related risk factors associated to sub-optimal vaults in eyes implanted with implantable collamer lenses

Background

To identify biometric and implantable collamer lens (ICL)-related risk factors associated with sub-optimal postoperative vault in eyes implanted with phakic ICL.

Methods

This study reports a retrospective case series of the first operated eye in 360 patients implanted with myopic spherical or toric ICL. Preoperatively, white-to-white (WTW), central keratometry (Kc) and central corneal thickness (CCT) were measured using the Pentacam. Anterior-segment optical coherence tomography (AS-OCT, Visante) was applied preoperatively for measuring the horizontal anterior-chamber angle-to-angle distance (ATA), internal anterior chamber depth (ACD), crystalline lens rise (CLR), anterior-chamber angle (ACA) and postoperatively the vault. Eyes were divided into three vault groups: low (LVG: ≤ 250 μm), optimal (OVG: > 250 and < 1000 μm) and high (HVG: ≥ 1000 μm). Multinomial logistic regression (MLR) was used to find the sub-optimal vault predictors.

Results

MLR showed that CLR, ICL size minus the ATA (ICL size-ATA), age, ICL spherical equivalent (ICLSE) and ICL size as contributing factors for sub-optimal vaults (pseudo-R² = 0.40). Increased CLR (OR: 1.01, CI: 1.00–1.01) and less myopic ICLSE (OR: 1.22, CI: 1.07–1.40) were risk factors for low vaults. Larger ICL size-ATA (OR: 41.29, CI: 10.57–161.22) and the 13.7 mm ICL (OR: 7.08, CI: 3.16–15.89) were risk factors for high vaults, whereas less myopic ICLSE (OR: 0.85, CI: 0.76–0.95) and older age (OR: 0.92, CI: 0.88–0.98) were protective factors.

Conclusion

High CLR and low ICLSE were the major risk factors in eyes presenting low vaults. In the opposite direction, ICL size-ATA was the major contributor for high vaults. This relationship was more critical in higher myopic ICLSE, younger eyes and when 13.7 mm ICL were used. The findings show that factors influencing the vault have differentiated weight of influence depending on the type of vault (low, optimal or high).

Supplementary Information

The online version contains supplementary material available at 10.1186/s40662-021-00250-6.

Intraoperative Versus Postoperative Vault Measurement After Implantable Collamer Lens Implantation in a Large Cohort of Patients

PURPOSE

To compare intraoperative and postoperative central vault measurement after implantable Collamer lens (ICL; STAAR Surgical) implantation using optical coherence tomography (OCT).

METHODS

A total of 574 eyes of 338 consecutive patients undergoing myopic ICL implantation were evaluated (mean age of 30.8 ± 5.7 years, 117 men and 221 women). Central ICL vault was measured both intraoperatively using the microscope-integrated iOCT (Optomedical Technologies GmbH) mounted on a standard surgical microscope (HS Hi-R NEO 900A; Haag-Streit Surgical GmbH), and postoperatively using the CASIA2 swept-source OCT (Tomey GmbH) at 4 and 24 hours.

RESULTS

Mean differences between intraoperative and postoperative vault values were 11.5 ± 29.0% of the mean value 4 hours postoperatively (P < .001) and 2.7 ± 33.5% of the mean value 24 hours postoperatively (P < .001). Correlation analysis shows significant agreement between vault values obtained intraoperatively and at the two postoperative times, 4 hours (Spearman Rho = 0.850, P < .001) and 24 hours (Spearman Rho = 0.745, P < .001). In 73% of cases, postoperative vault values 4 hours after the surgery could be predicted from intraoperative vault values, and so were 56% of vault values 1 day after surgery. Significant differences in vault were found at the different times, grouping cases by ICL size (Kruskal-Wallis, P = .028 for intraoperative vault, and P < .001 for both postoperative vault times), with smaller vault values for the smaller ICL size.

CONCLUSIONS

Intraoperative determination of ICL vault using iOCT is an effective method for predicting postoperative ICL vault and minimizing postoperative vault surprises that could require surgical retouching. [J Refract Surg. 2021;37(7):477-483.].

Long-term evaluation of anterior lens density after implantable collamer lens V4c implantation in patients with myopia over 40 years old

Purpose

To investigate the long-term safety and efficacy of implantable collamer lens (ICL) V4c implantation and changes in the anterior lens density (ALD) in patients with myopia ≥40 years of age.

Methods

This prospective study included 104 eyes of 52 patients >40 years of age before ICL V4c implantation. Spherical equivalent (SE), uncorrected distance visual acuity, corrected distance visual acuity (CDVA), intraocular pressure, endothelial cell density, anterior chamber depth, anterior chamber volume and anterior chamber angle preoperatively, at 1 and 3 months, and at 3 years postoperatively were recorded. Pentacam HR was used to analyse ALD changes at a depth of 0.5, 1.0 and 1.5 mm within a 3 mm diameter range around the pupil’s centre.

Results

The overall follow-up was uneventful at 42±7.1 months; the safety index at last follow-up was 1.26±0.35 and the efficacy index was 0.91±0.41. No eye lost the Snellen line of CDVA, 76% of the eyes had an increase in CDVA for ≥1 line and 62% had an SE within ±0.50 dioptre. The increase in ALD at 0.5, 1 and 1.5 mm was 16.52%±10.46%, 16.72%±9.85% and 17.28%±11.93%, respectively. Preoperative, 1-month and 3-month postoperative ALDs showed correlations with SE and age, and ALD at last follow-up was correlated only with age. There was no correlation between ALD and any other parameters.

Conclusion

ICL V4c shows long-term safety and efficacy in people ≥40 years of age. ALD increased in such patients, which may be related to age and SE.

Seven-year follow-up of posterior chamber phakic intraocular lens with central port design

BACKGROUND

To assess the clinical outcomes of the Visian Implantable Collamer Lens (ICL) with a central port throughout 7 years of follow-up.

METHODS

Eighty-four eyes of 52 patients were evaluated over a follow-up period of 7 years after V4c ICL implantation. Uncorrected (UDVA) and corrected (CDVA) distance visual acuities, refraction, intraocular pressure (IOP), endothelial cell density (ECD) and vault were analysed.

RESULTS

The mean postoperative UDVA (logMAR) was 0.04 ± 0.11, 0.13 ± 0.19 and 0.17 ± 0.23 at 1-, 5- and 7-years, respectively (P < 0.0001). The mean CDVA (logMAR) remains unchanged throughout a 7-year follow-up period (0.02 ± 0.08 and 0.02 ± 0.08, at 5- and 7-years, respectively, P = 0.2). At all follow-up visits, more than 95% of the eyes achieved a CDVA of 20/25 or better and more than 85% a CDVA of 20/20. At the end of the follow-up (7 years), no eye lost more lines of CDVA, 56 eyes (66.7%) and 28 eyes (33.3%) gained lines of CDVA. At 7-years, the spherical equivalent was - 0.62 ± 0.62 D. No significant increase in IOP (> 20 mmHg or an increase higher than 5 mmHg) occurred in any case throughout the 7-year of follow-up. The loss in ECD from the preoperative baseline at the last follow-up visit was 2.6%. No intraoperative or postoperative complications or adverse events occurred during the follow-up period.

CONCLUSIONS

The outcomes of this study show the long-term viability of the V4c ICL implantation as a surgical option for the correction of myopia.

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.

Changes in anterior lens density after Implantable Collamer Lens V4c implantation: a 4-year prospective observational study

PURPOSE

To investigate the changes in anterior lens density with a Pentacam after Implantable Collamer Lens (ICL) V4c implantation in patients with myopia.

METHODS

This prospective case series examined 62 eyes of 32 patients (mean age, 28.5 ± 5.73 years) with myopia or myopic astigmatism after ICL V4c implantation. Uncorrected distance vision acuity, corrected distance vision acuity (CDVA), manifest refraction, intraocular pressure, anterior chamber depth (ACD), anterior chamber volume (ACV), anterior chamber angle (ACA), endothelial cell density and Pentacam images of lens density were obtained pre- and postoperatively. The vault was obtained during the follow-ups.

RESULTS

Patients were followed up for an average of 51 ± 2.7 months (range, 48-57 months). All surgeries were uneventful, without any complication. The efficacy and safety indices at the last follow-up were 1.03 ± 0.2 and 1.22 ± 0.22, respectively. No eye had decreased CDVA, and 66% eyes gained ≥1 line. Furthermore, refractive error in 90% eyes was within ±0.50 D and that of 100% was within ±1.0 D of the attempted refraction. Anterior average lens density (a-ALD) in the 0.5-, 1.0- and 1.5-mm depth zones increased by 10.41 ± 11.51%, 17.1 ± 11.09% and 16.76 ± 10.4%, respectively, compared to preoperative values (all p < 0.05). The change in a-ALD between two different age groups was not significant. Moreover, there were no significant correlations between the change in a-ALD and age, preoperative spherical equivalent, ACD, ACA, ACV or vault.

CONCLUSIONS

Implantable Collamer Lens (ICL) V4c implantation demonstrates safety and efficacy for myopia correction. Although a-ALD increased slightly at 4 years postoperatively, no cataract developed during the follow-up. Further studies should investigate the reason for the postoperative increase in a-ALD.

Clinical Prediction of Excessive Vault After Implantable Collamer Lens Implantation Using Ciliary Body Morphology

PURPOSE

To determine the factors related to the ciliary body that are predictive of outcomes of excessive vault (> 1,000 µm) after Implantable Collamer Lens (ICL V4c; STAAR Surgical) implantation.

METHODS

In this retrospective case-control study, 27 eyes of 27 patients who presented with excessive vault (> 1,000 µm) following implantation of an ICL V4c were matched in a 1:2 ratio with those who presented with a normal vault (250 to 1,000 µm) on white-to-white distance, anterior chamber depth, and ICL size. The preoperative biometric parameters and clinical outcomes were compared between the two groups. The relationship between the postoperative vault and various variables was assessed by multiple linear regression analysis. Conditional logistic regression models were used to estimate odds ratios (ORs) and 95% CIs for excessive vault.

RESULTS

The vault value 1 month postoperatively was associated with preoperative anterior chamber volume, iris-ciliary angle, and crystalline lens rise (P < .05). In the conditional regression logistic analysis, every 1° reduction in iris-ciliary angle was associated with 4% increased odds of vault greater than 1,000 µm (OR = 0.96; 95% CI = 0.93 to 0.99; P < .001) and the anteriorly positioned ciliary body was associated with an increased risk of excessive vault after ICL implantation (OR = 3.57; 95% CI = 1.67 to 7.63; P < .001). In the excessive vault group, 1 eye underwent the ICL extraction and 3 eyes had an ICL exchange for a smaller ICL. After the ICL exchange, the mean value of postoperative vault decreased from 1,525.67 ± 468.22 to 810.33 ± 254.92 µm.

CONCLUSIONS

Eyes with an anteriorly positioned ciliary body were associated with a higher rate of excessive vault after ICL implantation, so the size of the ICL may need to be adjusted in these patients. Assessment of ciliary body characteristics adds significant information to the prediction of excessive vault after surgery. [J Refract Surg. 2020;36(6):380-387.].

A Case of Implantable Collamer Lens (ICL) with Reverse Orientation for 10 Years

Background

Implantable collamer lens (ICL) might rarely cause complications that warrant explantation. Here, we presented a case of inverted ICL that has undergone explantation after a 10-year duration. Case Presentation. A 49-year-old male with past ocular history of ICL implantation 10 years ago presented complaining of progressive decrease of visual acuity in the left eye for a long time. On examination, decreased visual acuity, anterior subcapsular cataract, and low ICL vault were noted. The anterior segment optical coherence tomography (AS OCT) showed inverted ICL. The ICL was explanted, and cataract surgery was done.

Conclusion

Inverted ICL should be kept in mind as a rare cause of long-term poor visual acuity in patient with a history of ICL surgery.

A four-year observation of corneal densitometry after implantable collamer lens V4c implantation

Background

To observe the changes in corneal densitometry (CD) with a Pentacam after implantable collamer lens (ICL) V4c implantation in myopia patients, and to investigate potential influencing factors.

Methods

We reviewed 65 eyes of 33 patients (mean age, 29.08±5.54 years) with myopia or myopic astigmatism who underwent ICL V4c implantation. Clinic parameters and Pentacam images of corneal topography and CD were obtained pre- and postoperatively.

Results

After an average of 52±2.2 months follow-up, the efficacy and safety indexes assessed at the last follow-up were 1.03±0.18 and 1.21±0.21, respectively. Except in the central annular zone of 0-2 mm, the CD values increased significantly at postoperative day 1 and decreased significantly until postoperative 1 year (P<0.05). The increase in CD values at different annular zones at postoperative day 1 was ranked as: 0-2 mm <2-6 mm < 6-10 mm. No significant difference was observed in corneal density at 1 week, 1 month, and 1-year follow-up when compared with the preoperative value (P>0.05). The CD value at 4 years follow-up increased significantly and correlated positively with age and preoperative uncorrected distance visual acuity, and negatively with preoperative spherical equivalent and intraocular pressure (IOP) (P<0.05).

Conclusions

ICL V4c implantation demonstrated safety and efficacy for myopia correction. The CD value increased at 4 years postoperatively and correlated with age, preoperative spherical equivalent, uncorrected distance visual acuity, and IOP.

Repeated rotation of a toric implantable collamer lens: A case report

INTRODUCTION

Implantable collamer lens have been used widely worldwide, and have been accepted by more and more doctors and patients due to good safety, stability, and effectiveness. However, there is still a problem of crystal rotation. The large angle rotation (over 10°) would weaken the original astigmatism correction effect and even induce irregular astigmatism, seriously affecting the visual quality of patients. Herein, we reported a case who had 2 times of crystal rotations after toric implantable collamer lens (TICL) implantation.

PATIENT CONCERNS

The patient was a 38-year-old man who underwent TICL implantation for the correction of high myopic astigmatism in eyes. He presented a sudden decrease in the visual acuity (VA) of the left eye 4 months after the TICL implantation. The uncorrected visual acuity (UCVA) was 8/20 (refraction, +2.25 -5.25 × 68).

DIAGNOSIS

Rotation of TICL was diagnosed. The toric marks with a rotation of 75° counter-clockwise from the original position were observed.

INTERVENTIONS

The TICL was re-set to the original position, leading to the UCVA of 12/20 in the left eye (refraction, -0.00 -0.75 × 131), with the vaulting of 589 μm. Ten months after the TICL relocation, the patient again presented a sudden decrease in the VA of the left eye, with the UCVA of 2/20 (refraction, +2.25 -5.00 × 66). Again, the toric marks with a rotation of 75° counter-clockwise from the original position was observed, just at the same position as the last rotation. This time, the TICL was removed. The axis and power were recalculated, and a new TICL was implanted, with the rotation of 73° counter-clockwise from the horizontal line of the temporal side.

OUTCOMES

The patient obtained a final UCVA of 12/20 in the left eye (refraction, +0.50 -0.50 × 26), which remained stable in the 6-month follow-up period, with the vaulting of 602 μm.

LESSONS

Rotation is a common complication after TICL surgery. Relocation or replacement of TICL are safe and efficient ways to recover VA due to TICL rotation.

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

PURPOSE

To compare the safety, efficacy, and patient-reported quality of vision of small incision lenticule extraction (SMILE) and implantable Collamer lens (ICL) implantation for the treatment of high myopia.

METHODS

A database of 1,634 SMILE (Carl Zeiss Meditec AG, Jena, Germany) and 225 ICL implantation (STAAR Surgical, Monrovia, CA) procedures was screened for patients with a binocular preoperative manifest refraction spherical equivalent between -6.00 and -10.00 diopters (D) and plano target refraction. One-to-one matching was performed by preoperative manifest refraction spherical equivalent, age, and pupil size. All identified patients were then prospectively examined at their next regular postoperative follow-up visit and presented with the standardized and clinically validated Quality of Vision questionnaire to gauge patient-reported postoperative visual quality.

RESULTS

A total of 80 eyes (40 patients) were eligible for 1:1 matching. Mean postoperative follow-up was 27.8 ± 14.3 months in the SMILE group and 26.6 ± 17.7 months in the ICL group (P = .44). Regarding the percentage of eyes within ±0.50 D of plano target, refractive predictability was better in eyes treated with ICL implantation (90%) than SMILE (72.5%) (P = .045). Mean UDVA was comparable (ICL: -0.09 ± 0.10 logMAR; SMILE: -0.06 ± 0.09 logMAR; P < .09), but the efficacy (1.28 vs 1.05; P < .001) and safety (1.31 ± 0.22 vs 1.10 ± 0.25; P < .001) indices were higher after ICL implantation. ICL implantation induced significantly fewer higher order aberrations (total higher order aberrations: SMILE 0.724 ± 0.174 µm vs ICL 0.436 ± 0.114 µm; P < .01). Regarding subjective quality of vision, patients who had ICL implantation were significantly less bothered by visual disturbances, which were mainly halos after ICL and starbursts and fluctuations of vision after SMILE (P < .05).

CONCLUSIONS

In this refraction-matched comparative study, ICL implantation for high myopia yielded better refractive accuracy, better uncorrected distance visual acuity, fewer higher order aberrations, and better subjective quality of vision than SMILE. [J Refract Surg. 2020;36(3):150-159.].

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.

Comparison of anterior chamber angle changes following phakic intraocular lens with and without a central hole implantation for moderate to high myopic eyes

The aim of this study was to compare the anterior chamber angle changes after implantation of phakic intraocular lens with and without a central hole for moderate to high myopic eyes in Chinese people.This study enrolled 106 eyes of 54 people with intraocular lens V4 implantation and 105 eyes of 53 people with intraocular lens V4c implantation. Postoperative vault, intraocular pressure, and anterior chamber angle changes were assessed using noncontract tonometer and ultrasound biomicroscope, respectively, at 1, 3, 6, and 12months after the surgery.There were no significant differences (all P > .05) between the 2 groups in the depth of the central vault, intraocular pressure, or the width of anterior chamber angle at any time point post-surgery. The anterior chamber angle width in degree had a baseline of 54.40 ± 10.51 in V4c group, and decreased to 27.80 ± 5.62, 26.95 ± 5.56, 27.32 ± 5.66, 27.04 ± 5.47 at 1, 3, 6, and 12 months post-surgery, respectively. Mean preoperative value of 50.62 ± 11.77 decreased to 27.28 ± 6.53, 26.82 ± 6.03, 26.61 ± 5.80, 26.83 ± 5.76 at 1, 3, 6, 12 months, respectively, in V4 group. It had sufficient evidence (P < .001) that anterior chamber angle will narrow done after surgery, but there were no statistically significant differences within groups at any time point after surgery.The anterior chamber angle changes of the V4c group was essentially equivalent to that of conventional V4 group, although implantation of both models will lead to the decrease in anterior chamber angle width.

Phakic intraocular lens: Getting the right size

Phakic intraocular lenses (IOL) are a boon for patients who want spectacle independence but are unable to get refractive correction through laser platforms due to high refractive error or certain corneal contraindications. Phakic IOL's (PIOL) have their own set of complications and challenges, the most important being getting the sizing right. This paper attempts to solve the problem of accurate sizing of PIOL's. Parameters needed for calculating the ideal size of PIOL's have been studied in a step by step manner using all possible tools depending upon the availability and preference of the surgeon. The pros and cons of using a particular tool for measurements have been highlighted along with illustrative case examples to help surgeons who are starting PIOL implantation surgery.

Phakic intraocular lens implantation for the correction of hyperopia

The prevalence of myopia is much higher than hyperopia. Hence, there are relatively few studies investigating phakic intraocular lens (pIOL) implantation for the correction of hyperopia. This review aimed to summarize the available relevant literature on the efficacy and safety of pIOL implantation for the correction of hyperopia and hyperopic astigmatism. At present, two types of pIOLs are used to correct hyperopia and hyperopic astigmatism: anterior chamber iris-fixated pIOLs and posterior chamber implantable collamer lenses. Both have been found to be safe and effective. No serious events (eg, retinal or choroidal detachment, endophthalmitis) were reported in the reviewed articles. Implantation of pIOLs might be the optimal refractive surgery for the correction of high hyperopia.

Long-term In Vivo Stability of Posterior Chamber Phakic Intraocular Lens: Properties and Light Transmission Characteristics of Explants

PURPOSE

To evaluate the in vivo durability of the surface and optical properties of the implantable Collamer lens (ICL).

DESIGN

Retrospective case series.

METHODS

We included patients who developed cataracts after having undergone ICL implantation from March 2003 to May 2014 and underwent ICL explantation followed by cataract surgery from March 2017 to December 2019 at the Nagoya Eye Clinic. ICL explants were submitted to Chukyo Medical Co, Ltd (Nagoya City, Japan) for laboratory analysis using ultraviolet-visible light spectroscopy, light microscopy (LM), and scanning electron microscopy. Patients' demographic and clinical data were collected and reviewed.

RESULTS

Thirteen eyes from 10 patients were studied. The average age at ICL explantation was 50.5 ± 8.5 years (range, 34.5-66.3 years). The average length of ICL stay in the eye (from implantation to explantation) was 10.5 ± 2.7 years (range, 4.4-13.7 years). No opacification or coloring of the ICL explants was observed by LM. The ICL explants showed almost the same light transmittance as that of unused ICLs. Scanning electron microscopy revealed no irregularities at the surface of the center and periphery of the optic and haptic footplate. The positioning holes did not show any deposition.

CONCLUSION

The ICLs remained in-eye for >10 years without any deterioration in the surface and optical properties of the ICL, despite their contact with the ciliary body and iris tissues and the continuous interaction with the aqueous humor components. The present study shows long-term in vivo stability of the ICL.

Application of a Partial Least Squares Regression Algorithm for Posterior Chamber Phakic Intraocular Lens Sizing and Postoperative Vault Prediction

PURPOSE

To develop and validate a new algorithm for predicting the postoperative vault of the myopic EVO Visian Implantable Collamer Lens (ICL) V4c (STAAR Surgical AG).

METHODS

This study included 81 eyes of 43 patients who had undergone ICL implantation. Preoperative data obtained by swept-source optical coherence tomography, Scheimpflug camera, and anterior segment optical coherence tomography were applied to develop a new partial least squares (PLS) regression algorithm. ICL sizing was performed using the standard white-to-white method with the online calculation and ordering system. The postoperative vault was assessed based on anterior segment optical coherence tomography. The PLS approach was applied to create the calibration model for predicting the postoperative vault. The new PLS model was cross-validated using the leave-one-out method and compared to a recently published linear regression model. Agreement between the actual and predicted vault values for the two methods was assessed by the Bland-Altman method.

RESULTS

There was a statistically significant correlation (P < .001, r = 0.73) between the postoperative vault values and those predicted by the PLS algorithm. Validation of the PLS model yielded lower mean differences and limits of agreement (0 and 410 µm, respectively) than the linear regression method (400 and 750 µm, respectively).

CONCLUSIONS

The PLS algorithm increases the precision of ICL vault prediction. However, it shows a tendency to overestimate small vault values and underestimate high vaults. [J Refract Surg. 2020;36(9):606-612.].

Refractive surgery beyond 2020

Refractive surgery refers to any procedure that corrects or minimizes refractive errors. Today, refractive surgery has evolved beyond the traditional laser refractive surgery, embodied by the popular laser in situ keratomileusis or 'LASIK'. New keratorefractive techniques such as small incision lenticule extraction (SMILE) avoids corneal flap creation and uses a single laser device, while advances in surface ablation techniques have seen a resurgence in its popularity. Presbyopic treatment options have also expanded to include new ablation profiles, intracorneal implants, and phakic intraocular implants. With the improved safety and efficacy of refractive lens exchange, a wider variety of intraocular lens implants with advanced optics provide more options for refractive correction in carefully selected patients. In this review, we also discuss possible developments in refractive surgery beyond 2020, such as preoperative evaluation of refractive patients using machine learning and artificial intelligence, potential use of stromal lenticules harvested from SMILE for presbyopic treatments, and various advances in intraocular lens implants that may provide a closer to 'physiological correction' of refractive errors.

A systematic review about the impact of phakic intraocular lenses on accommodation

Phakic intraocular lenses (pIOL) are the main treatment for patients who have either high ametropia or contraindications for laser refractive surgery. The main feature that makes this kind of lenses suitable for its implantation in young adults searching for independence of optical prescription is the conservation of accommodation, since lens extraction is not required. A systematic review has been performed to evaluate the scientific literature on the effect of pIOL implantation on accommodation. Critical assessment of the articles included in the review was achieved using the tool Critical Appraisal Skills Programme in its Spanish form (CASPe). After revising the complete text of 10 articles pre-selected, two quasi-experimental pre-post studies evaluating the outcomes of a specific model of posterior chamber pIOL were included in the systematic review. The CASPe scoring of both studies were 5/11. According to this outcome, the evidence describing the impact of the pIOL implantation on the accommodative function can be defined poor. Some trends are reported as the decrease in the amplitude of accommodation, a decrease positive relative accommodation and improvement of accommodation. However, these results should be confirmed in future controlled studies.

Short-time evaluation on intraocular scattering after implantable collamer lens implantation for correcting high myopia

Background

To compare the intraocular scattering before and after implantation of implantable collamer lens (ICL) V4c for correction of high myopia in a short term.

Methods

In this study, 38 eyes of 19 patients who underwent the implantation of ICL V4c were followed up for 3 months. Uncorrected visual acuity (UCVA), best corrected visual acuity (BCVA), objective scattering index (OSI), modulation transfer function cutoff frequency (MTF cutoff), strehl ratio (S/R), OV100%, OV20% and OV9% were measured pre- and postoperatively. Meantime, the Pseudophakic Dysphotopsia Questionnaire (PDQ) was scored to evaluate the subjective satisfaction of intraocular scattering pre- and postoperatively.

Results

The UCVA were − 0.02 ± 0.06, − 0.03 ± 0.07 and − 0.04 ± 0.07 logMAR at 1 week, 1 month and 3 months postoperatively which were significantly better than those preoperatively (P < 0.05). The BCVA were − 0.09 ± 0.09, − 0.09 ± 0.1 and − 0.1 ± 0.11 logMAR at 1 week, 1 month and 3 months after surgery, which were better than those before surgery significantly (t = 15.64, P < 0.05). The mean OSI were 2.37 ± 1.6, 1.63 ± 0.94, 1.5 ± 0.86 and 1.43 ± 1.05 preoperatively, 1 week, 1 month and 3 months postoperatively which was found significant difference (F = 12.92 P < 0.05). No significant differences were found in MTF cut off (F = 0.61, P = 0.62), S/R (F = 0.58, P = 0.36), OV100% (F = 0.966, P = 0.65), OV20% (F = 0.121, P = 0.96) and OV9% (F = 1.01, P = 0.30) between pre- and postoperatively. The PDQ results indicated that intraocular scattering reduced at 3 months after surgery significantly (P < 0.05).

Conclusions

The ICL V4c implantation for correcting high myopia induced less intraocular scattering and visual disorder than spectacle correction.

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

Background

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

Methods

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

Results

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

Conclusions

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

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.

Femtosecond laser assisted cataract surgery in a cataract patient with a "0 vaulted" ICL: a case report

BACKGROUND

Femtosecond laser assisted cataract surgery (FLACS) combined with implantable collamer lenses (ICLs) extraction has been shown to be a feasible method for patients developing cataracts after the ICL implantation. All reported cases had shallow vaults, ranging from 47 μm (μm) to 100 μm. We report for the first time, a case in which the FLACS was performed on the "0" vault eye.

CASE PRESENTATION

A 38-year-old man with anterior subcapsular cataracts underwent the FLACS combined with ICLs extraction 6 years after ICLs implantation in both eyes. In his left eye, the ICL touched the anterior capsule, existing "0" vault. During the capsulotomy, cavitation bubbles were trapped in the shallow space beneath the ICL, developing from small bubbles into big ones, which resulted in the incomplete capsulotomy. Comparatively, in the right eye, the ICL vault was measured 72 μm, and the capsulotomy was complete and no big cavitation bubbles formed. In both eyes, capsulotomy zones were manually assigned to the anterior capsule surface in the process of laser identification. However, the nuclear pre-fragmentations were unsuccessful in both eyes. Other steps of surgeries were performed uneventfully. Depending on the design of monovision, the uncorrected distance visual acuity (UDVA) was 20/32, and the near uncorrected visual acuity (UCVA) was 20/25 in both eyes postoperatively.

CONCLUSIONS

This case suggested that the surgeon should pay attention to the incomplete laser capsulotomy when using a femtosecond laser in cataractous cases with "0" vaulted ICLs, and manual adjustment was required in the process of laser identification.

Optical quality after posterior chamber Phakic implantation of an intraocular Lens with a central hole (V4c implantable Collamer Lens) under different lighting conditions

Background

The current study compared optical quality before and after implantation of a posterior chamber phakic intraocular lens with a central hole [V4c implantable collamer lens (ICL)] under bright and dark lighting conditions by means of the Optical Quality Analysis System™ (OQAS; Visiometrics, Terrassa, Spain).

Methods

This prospective study involved 91 eyes of 46 consecutive high myopia patients (15 males and 31 females, average spherical equivalent − 10.50 ± 0.33D) undergoing implantation of a V4c ICL. The modulation transfer function (MTF) cutoff frequency, Strehl ratio, objective scattering index (OSI), and predicted visual acuities (PVAs; 100, 20, and 9%), under different lighting conditions, were measured before and 1 week, 1 month, and 3 months after surgery.

Results

All optical parameters showed significant improvements, at all time points, under dark condition after surgery. We observed no significant changes in PVA 9% at 1 week (mean value 0.539, P = 0.12) or 1 month after surgery (mean value 0.573, P = 0.08) under bright condition; but all other postoperative parameters improved significantly. Comparing the two lighting conditions, the OSI decreased more under dark conditions at 1 week (P = 0.02), 1 month (P = 0.004), and 3 months (P = 0.002), but there was no significant difference in any other parameter. In addition, patients were divided into super high myopia (group S, spherical equivalent greater than − 10 D) and high myopia (group H, spherical equivalent from − 6 D to − 10 D), the group S improved significantly more than group H in all parameters, under both bright and dark conditions.

Conclusions

V4c ICL implantation improved optical quality under both bright and dark lighting conditions, and had a better ability to reduce the extent of scattering in the dark. Furthermore, group S achieved greater improvement in visual quality, which should be considered by physicians before surgery.

One-year natural course of corneal densitometry in high myopic patients after implantation of an implantable collamer lens (model V4c)

BACKGROUND

Corneal densitometry, which is also known as corneal backscattering, is a surrogate measure of corneal clarity. The purpose of the study was to investigate the changes in corneal densitometry (CD) after implanting an implantable collamer lens (ICL-V4c).

METHOD

Twenty-six high myopic patients (aged 29.3 ± 6.6 years, 6 males and 20 females) who underwent ICL-V4c implantation were enrolled. Intraocular pressure (IOP), corneal topography, corneal densitometry, uncorrected distance visual acuity (UCDVA), manifest refraction, and best corrected distance visual acuity (BCDVA) were evaluated pre-operatively and at 1 day, 1 week, and 1, 3, 6, and 12 months post-operatively. Endothelial cell density (ECD) was measured pre-operatively and at 3, 6, and 12 months post-operatively. The efficacy index (mean post-operative UCDVA / mean pre-operative BCDVA) and the safety index (mean post-operative BCDVA / mean pre-operative BCDVA) were evaluated at 1 month, 3 months, 6 months and 12 months post-operatively.

RESULTS

Over the annular diameters of 0-2 mm, the pre-operative densitometry values of the anterior layer, central layer, posterior layer, and total layer were 20.1 ± 2.8, 11.8 ± 1.1, 10.5 ± 0.9 and 14.1 ± 1.5, respectively. From pre-operatively to post-operative Month 12, the values changed insignificantly (P = 0.177, P = 0.153, P = 0.543 and P = 0.207, respectively). Over the annular diameters of 2-6 mm, the pre-operative mean densitometry values were 17.9 ± 2.2, 10.5 ± 0.9, and 12.6 ± 1.2, respectively. From pre-operatively to post-operative Month 12, the values decreased to 16.5 ± 2.1, 10.0 ± 0.9, and 11.9 ± 1.2, respectively, which were similar to the pre-operative values (all P > 0.05) but significantly lower than the values obtained at post-operative Day 1 (P = 0.013, P = 0.002 and P = 0.010, respectively). The densitometry value of the posterior layer over the annular diameters of 2 to 6 mm remained unchanged (from 9.4 ± 0.7 to 9.1 ± 0.7) over time (P = 0.372). The efficacy and safety indices assessed at 12 months post-operatively were 1.04 ± 0.27 and 1.19 ± 0.23, respectively. The changes in IOP and ECD values were statistically insignificant (P = 0.896 and P = 0.968, respectively).

CONCLUSION

ICL-V4c implantation may be safe and efficient for high ametropia correction. The corneal densitometry values obtained over the annulus of 0-6 mm increased slightly from before the operation to post-operative Day 1 and then decreased gradually, which indicates that ICL-V4c implantation may not compromise corneal clarity.

Transient crystalline lens deposits following the insertion of a phakic sulcus-fixated collamer intraocular lens in a hyperopic eye

Purpose

The purpose of this study was to report crystalline lens deposit formation following ICL implantation for the correction of hyperopia.

Observations

A 23-year-old male presented at the American University of Beirut Medical Center in 2008 seeking refractive surgery for hyperopia. His cycloplegic refraction was +7–1.25 × 115° and +7–1.00 × 115° in the right and left eyes, respectively, yielding a vision of 20/20 bilaterally. The patient underwent right eye insertion of a non-toric phakic sulcus-fixated collamer lens 2 weeks after undergoing peripheral iridotomies. The early postoperative course was complicated by anterior chamber inflammation and the appearance of diffuse whitish precipitates on the anterior surface of the crystalline lens, hypotony, and a mid-dilated mildly reactive pupil. With the prompt administration of topical and systemic steroids, the anterior chamber reaction subsided, and the anterior capsular deposits gradually resolved peripherally with some remaining centrally over the course of several weeks. The patient's visual acuity at 6 months was 20/20.

Conclusionsand importance

Adequate viscoelastic removal and minimal iris stimulation seem to be essential to avoid this condition in hyperopic implants that lack a central port. Additionally, prompt treatment can minimize visual impairment and hasten visual recovery.