Implantable Collamer Lens Vault Research Articles

Prediction of footplate position after implantable collamer lens implantation based on iris and ciliary body morphologies.

To investigate the factors affecting footplate position and its influence on vault characteristics after implantable collamer lens (ICL) implantation. Hunan Provincial People's Hospital, Changsha, China. Retrospective case series. This study included 124 patients (124 eyes). Ultrasound biomicroscopy (UBM) was performed to assess the iris and ciliary body morphologies and observe the footplate position. Using multiple linear regression, the relationship between various ocular and ICL parameters and the vault as well as the factors affecting the footplate distance (FD) were analyzed. Based on the FD, 3 groups were formed: group 1 (<500 μm), group 2 (500 to 1000 μm), and group 3 (>1000 μm). The distribution of the vault range postoperatively was observed for the 3 groups. Ciliary sulcus angle and FD significantly affected the vault (adjusted R2 = 0.190, F = 6.763, P < .001), with FD being the most important factor influencing the vault (β = -0.383, P < .001). Postoperative UBM revealed that the footplate was located at different positions in the posterior chamber, with the majority (52%) being located on the ciliary body. The mean size of the 4 footplate orientations was 0.88 ± 0.24 mm. Multiple linear regression analysis revealed that ciliary body thickness (CBT), iris curvature (IC), and ICL iris contact length (IRCL) significantly influenced the FD (adjusted R2 = 0.373, F = 11.432, P < .001). The vault range differed significantly among the 3 groups (X 2 = 32.33, P < .001). Different postoperative ICL footplate positions significantly affect the vault. CBT, IC, and IRCL can alter the position of the footplate from the expected position. This study provides reference for ICL size selection and vault prediction.

Enhancing the Automated Detection of Implantable Collamer Lens Vault Using Generative Adversarial Networks and Synthetic Data on Optical Coherence Tomography.

To investigate the efficacy of incorporating Generative Adversarial Network (GAN) and synthetic images in enhancing the performance of a convolutional neural network (CNN) for automated estimation of Implantable Collamer Lens (ICL) vault using anterior segment optical coherence tomography (AS-OCT). This study was a retrospective evaluation using synthetic data and real patient images in a deep learning framework. Synthetic ICL AS-OCT scans were generated using GANs and a secondary image editing algorithm, creating approximately 100,000 synthetic images. These were used alongside real patient scans to train a CNN for estimating ICL vault distance. The model's performance was evaluated using statistical metrics such as mean absolute percentage error (MAPE), mean absolute error (MAE), root mean squared error (RMSE), and coefficient of determination (R2) for the estimation of ICL vault distance. The study analyzed 4,557 AS-OCT B-scans from 138 eyes of 103 patients for training. An independent, retrospectively collected dataset of 2,454 AS-OCT images from 88 eyes of 56 patients, used prospectively for evaluation, served as the test set. When trained solely on real images, the CNN achieved a MAPE of 15.31%, MAE of 44.68 µm, and RMSE of 63.3 µm. However, with the inclusion of GAN-generated and algorithmically edited synthetic images, the performance significantly improved, achieving a MAPE of 8.09%, MAE of 24.83 µm, and RMSE of 32.26 µm. The R2 value was +0.98, indicating a strong positive correlation between actual and predicted ICL vault distances (P < .01). No statistically significant difference was observed between measured and predicted vault values (P = .58). The integration of GAN-generated and edited synthetic images substantially enhanced ICL vault estimation, demonstrating the efficacy of GANs and synthetic data in enhancing OCT image analysis accuracy. This model not only shows potential for assisting postoperative ICL evaluations, but also for improving OCT automation when data paucity is an issue. [J Refract Surg. 2024;40(4):e199-e207.].

Anterior Segment Biometry During Accommodation After Posterior Chamber Phakic Implantable Collamer Lens Implantation.

To evaluate the dynamic changes in anterior segment parameters during accommodation following Implantable Collamer Lens (ICL) implantation with swept-source optical coherence tomography (SS-OCT). Under the accommodation of 0.00 diopters (D), 3.00 D, and maximum amplitude, SS-OCT was used to examine the anterior segment parameters, including ICL vault, ICL depth (the distance between the corneal endothelium and the posterior surface of ICL), crystalline lens thickness, anterior chamber depth, and various parameters of the anterior chamber angle, comprising angle opening distance, angle recess area, trabecular iris space area, and trabecular iris angle. During accommodation, the ICL vault showed a significant decrease from baseline (536 ± 278 μm) to 3.00 D (522 ± 281 μm), followed by an increase from 3.00 D to maximum amplitude (548 ± 306 μm) (analysis of variance [ANOVA], P < .001). Four eyes (2.61%) exhibited a decrease in ICL vault to less than 100 μm (47 ± 32 μm) at maximum accommodation. The ICL depth decreased significantly as accommodation increased (ANOVA, P < .001). Crystalline lens thickness increased, whereas anterior chamber depth decreased during accommodation (ANOVA, P < .001). The anterior chamber angle widened during 3.00 D of accommodation but narrowed at maximum accommodation, leading to significant changes in the angle opening distance, angle recess area, trabecular iris space area, and trabecular iris angle during accommodation (ANOVA, P < .001 for all). The anterior segment, including ICL vault and anterior chamber angle, undergo significant dynamic changes during accommodation. These accommodative changes may require careful monitoring for the surgery design of ICL implantation. [J Refract Surg. 2024;40(3):e164-e172.].

Clinical management of a nonoptimal vault and unexpected postoperative refraction in a patient implanted with a phakic intraocular lens

Introduction: This case reports the management of a bilateral toric implantable collamer lens (ICL) surgery with low vaulting and unilateral reduction in visual acuity (VA) associated with a combined effect of surgically induced astigmatism (SIA) and toric-ICL rotation. This case expands the common management of toric-ICL rotation, by adding surgically induced corneal changes. Patient and Clinical Findings: The patient presented with moderate myopia and high astigmatism and was implanted with a toric-ICL, resulting in bilateral low vault &lt;150 μm and unilateral VA reduction (20/40) because of postoperative oblique astigmatism, observed at the 4-week follow-up. Diagnosis, Intervention and Outcomes: The low ICL vaulting was associated with a high crystalline lens rise and underestimation of the sulcus-to-sulcus distance. The VA reduction resulted from a combined effect of ∼1.0 diopter SIA and 8-degree ICL rotation. The authors associate the high SIA to abnormal corneal biomechanics indexes and the toric-ICL rotation to a lack of stability resultant from a small ICL size. The left eye toric-ICL has exchanged with one with larger size and the power recalculated using vectorial analysis. The toric-ICL exchange increased the vault 75 μm and improved VA. Conclusions: Detailed anterior chamber morphometry and corneal biomechanics may assist in improving the refractive outcome in toric-ICL surgery.

Comparison of formulas in the implantable collamer lens vault prediction.

To compare the predictability of different formulas in the postoperative vault of an implantable collamer lens (ICL) surgery and assist physicians for formula selection in ICL implantation. This is a retrospective study. Patients who underwent ICL implantation between August 31, 2021 and October 29, 2021 at our clinic were reviewed. The clinical data, predicted ICL sizes and vaults, actual ICL size implanted and vaults at 1 month after surgery, and corresponding prediction formulas used were collected and analyzed. This study included 140 eyes from 72 patients (15 males and 57 females). Differences between ICL sizes recommended by the Visian ICL Online Calculation & Ordering System (OCOS) and NK formula (Version. 3) or KS formula (Version. 4) were statistically significant (P < .0001), except for the recommended ICL sizes between the NK and KS formulas (P > .05). Better consistency between predicted ICL vaults and achieved ICL vaults was observed when using the KS formula compared to the NK formula. The actual ICL vaults were 250 to 750 μm at 1 month after surgery in 66.4%, 76.5%, and 80.5% eyes of the OCOS, NK, and KS groups, respectively. There was significant difference between the OCOS and KS groups (P < .05), especially in the 12.6 mm ICL group. The KS formula is the most accurate formula for recommending an ICL size and vault prediction when compared to the NK formula and OCOS. Further studies for a more accurate formula are warranted.

Vertical rotation of phakic intraocular lens to achieve optimal vaulting in a myopic eye

Optimal implantable collamer lens (ICL) sizing and normal postoperative ICL vault are important to avoid adverse events. Spherical phakic intraocular lens (PIOL) implantation was done for a case of both eye myopia. Both eyes had similar ocular biometry, hence the same size PIOL was ordered. The right eye had postoperatively, a high posterior vault of 2000 μ on POD1, which reduced to 1000 μ on POD2. Re-evaluation confirmed similar ocular and PIOL parameters in both eyes. The PIOL was rotated 90° to a vertical rotation after which a reduction in the vault from 1000 to 700 μ was achieved. Satisfactory refractive outcome and optimal vault were maintained during subsequent visits. The left eye course was uneventful.

Presumed Unindicated Implantation of Posterior Chamber Phakic Intraocular Lens.

BACKGROUND Refractive surgery is one of the most frequently performed ocular surgeries worldwide. Implantation of the posterior chamber phakic intraocular lens has advantages over laser vision correction, especially in high refractive error cases. We present a case of a young adult women with poor vision who underwent bilateral posterior chamber phakic intraocular lens explantation due to high vault, shallow anterior chambers, and a picture of cone-rod dystrophy. CASE REPORT A 23-year-old woman was referred for poor vision following an implantation of bilateral toric implantable collamer lens (ICL) implantation when she was 18 years old for high myopic astigmatism and anisometropia. On presentation, the best corrected visual acuity was 4-6/200 and 2-3/200 in the right eye and left eye, respectively. Slit lamp examination indicated a clear cornea with pigment deposition on the endothelium, high ICL vault, shallow anterior chamber, and bowing of the iris bilaterally. The patient underwent bilateral removal of the ICLs on separate visits, yet the vision remained unchanged. Diagnostics revealed that the patient had bull's eye maculopathy with atrophy due to her cone-rod dystrophy, which caused the poor vision. CONCLUSIONS This report emphasizes the need for careful and appropriate patient and intraocular size selection for refractive surgery. It indicates the importance of thorough medical examination, including genetic testing, fundus examination, and optical coherence tomography when retinal dystrophy is suspected. Generally, close follow-up is crucial in the setting of high vaulting following ICL implantation to prevent secondary complications.

Deep Learning–Based Estimation of Implantable Collamer Lens Vault Using Optical Coherence Tomography

To develop and validate a deep learning neural network for automated measurement of implantable collamer lens (ICL) vault using anterior segment optical coherence tomography (AS-OCT). Cross-sectional retrospective study. Multicentric. A total of 2,647 AS-OCT anonymized eye scans were used from 139 eyes of 82 subjects who underwent ICL surgery in 3 different centers. Using transfer learning, a deep learning neural network algorithm was trained and validated for the regression task of estimating the ICL vault on the MS-39 OCT (CSO, Florence, Italy). A trained operator separately reviewed all OCT scans and measured the central vault using a built-in OCT caliper tool. The model was then separately tested on 191 AS-OCT scans. A Bland-Altman plot was constructed and the mean absolute percentage error (MAPE), the mean absolute error (MAE), the root mean squared error (RMSE), the Pearson correlation coefficient (r), and the determination coefficient (R2) were calculated to evaluate the strength and validity of the model. On the test set, the model achieved a MAPE of 3.42%, an MAE of 15.82 µm, an RMSE of 18.85 µm, a Pearson correlation coefficient r of +0.98 (P-Value < .00001), and a coefficient of determination R2 of +0.96. There was no significant difference between the vaults of the test set labeled by the technician versus those estimated by the model: 478 ± 95 µm versus 475 ± 97 µm, respectively, P-Value = 0.064). Using transfer learning, our deep learning neural network was able to accurately compute the ICL vault from AS-OCT scans, overcoming the limitations of an imbalanced dataset and limited training data. Such an algorithm can assist the postoperative assessment in ICL surgery. PRéCIS: This study develops and validates a deep learning model to accurately estimate implantable collamer lens vault on optical coherence tomography using transfer learning, convoluted neural networks, and regression.

Nine Years' Follow-up of Bilateral Extremely Low Vaulting of Implantable Collamer Lens: Case Report

Purpose: To present a patient with bilateral implantable Collamer lens (ICL) implantation with extremely low vault who was followed up over 9 years and in whom no cataract was detected. Methods: A 56-year-old woman underwent uneventful bilateral ICL implantation and her postoperative ICL vaulting was 10 and 8 µm in the right and left eye, respectively. After consultation with the patient, it was decided to withhold surgical intervention and follow up closely. Results: Nine years postoperatively, the patient had normal ophthalmological examination results: uncorrected distance and near visual acuity of 20/20, normal intraocular pressure and open angle, stable ICL with low vaulting of 8 to 12 µm, clear lens with stable Objective Scatter Index scores, and normal posterior segment. Conclusions: This case report shows that even though low ICL vault is a risk factor for cataract development, withholding surgical intervention should be considered depending on the patient's age, characteristics, and compliance with close follow-up. [ Journal of Refractive Surgery Case Reports. 2023;3(1):e5–e9.]

ICL Postimplantation Decentration and Tilt in Myopic Patients with Primary Iridociliary Cysts.

To observe the decentration and tilt of implantable collamer lens (ICL) as well as possible visual effects postimplantation in primary iridociliary cysts. The present investigation was a retrospective cohort study. All 48 patients (91 eyes) who underwent ICL surgery at the Center of Refraction Surgery of Tianjin Medical University Eye Hospital between July 2018 and May 2020 were split into two groups based on the absence or presence of primary iridociliary cysts established by ultrasonic biological microscopy (UBM) examination. Intraocular pressure (IOP), corrected distance visual acuity (CDVA), uncorrected distance visual acuity (UDVA), anterior chamber angle (ACA), anterior chamber volume (ACV), and anterior chamber depth (ACD) were recorded preoperatively and postoperatively at 1, 6, and 12 months. Additionally, we performed an analysis of the ICL vault, decentration, and tilt using a rotating Scheimpflug Oculus Pentacam camera system at 1, 6, and 12 months after surgery. No serious complications were observed. Significant postoperative improvement (P < 0.05) of UDVA was established in the two studied groups; however, we did not observe statistically significant intergroup differences (P > 0.05) throughout the entire research period. In each group, the preoperative ACA, ACV, and ACD were statistically significantly reduced (P < 0.05), but no such decrease was established between their postoperative values (P > 0.05). We observed no statistical differences between both groups with regard to their values of IOP, ACA, ACV, ACD, ICL vault, ICL decentration, and tilt at 1, 6, and 12 months after surgery. Similarly, no statistically significant within-group correlation (P > 0.05) of the decentration of ICL and the tilt and the CDVA values was established. No postimplantation effect of ICL with a central hole on vision was established in myopia patients with primary iridociliary cysts, within certain limits of ICL decentration and tilt values.

Descriptive Analysis of Footplate Position After Myopic Implantable Collamer Lens Implantation Using a Very High-Frequency Ultrasound Robotic Scanner.

To assess the position of the haptics of the implantable collamer lens (ICL) in myopic eyes using a high-frequency ultrasound robotic scanner. This was a prospective, single-arm, observational study carried out at the Instituto Zaldivar SA (Mendoza, Argentina) in a sample of 52 eyes who have been submitted to successful ICL implantation prior to enrollment. Images of the eyes were obtained using a very-high frequency digital ultrasound robotic scanner (VHFDU) to establish the position of the ICL in the posterior chamber and its relation to the ciliary sulcus. New parameters for lens position analysis were also described. In 81% of cases (42 eyes), the ICL rests on the ciliary body (CB) in both temporal and nasal sides, being slightly lower than 6% (3 eyes) those that rest on the sulcus in both sides, with significant correlations between ICL position and vault values (p<0.05). Cases in which the ICL position was CB-CB yielded central vault values across the whole range determined within the sample, but most of the eyes where the ICL rests on both the sulcus in one side and the CB in the other yield greater central vault values. Correlation was significant between ICL position and retroposition distance on the temporal side (Spearman's rho -0.487, p<0.001). A significant but weaker correlation was also found between ICL position and retroiridian space (p<0.05). ICL for myopia footplates tend to locate outside of the sulcus in a significant percentage of patients after successful implantation. VHFDU assessment in eyes implanted with an ICL to properly study the lens footplate position and posterior anatomical relations provides important additional information besides post-surgery vault.

Intraoperative adjustment of implantable collamer lens vault by lens rotation aided by intraoperative OCT.

To assess the use of intraoperative optical coherence tomography (OCT) to detect high vault during implantation surgery and guide intraoperative vault adjustment by implantable collamer lens (ICL) rotation. Instituto Zaldivar SA. Mendoza, Argentina. Prospective single-arm observational study. 25 eyes of 25 consecutive patients showing high intraoperative vault who had undergone ICL rotation from horizontal to vertical or oblique position were evaluated. Central ICL vault was measured both intraoperatively using the microscope-integrated iOCT mounted on a standard surgical microscope (HS Hi-R NEO 900A NIR) and postoperatively using the Casia 2 swept-source OCT at 4 hours, 1 day, and 1 month. 25 eyes of 25 consecutive patients showing high intraoperative vault who had undergone ICL rotation from horizontal to vertical or oblique position were evaluated. The mean vault value obtained intraoperatively was 1147.88 ± 188.36 μm and changed significantly to 739.76 ± 194.97 μm after lens rotation to either vertical (n = 19, 76% of cases) or oblique (n = 6, 24% of cases) positions (mean difference 408.12 ± 213.57 μm, P < .001). The amount of change due to lens rotation was significantly correlated with white-to-white distance ( r = -0.480, P = .015) and vault before rotation ( r = -0.564, P = .003). The mean vault values were 758.40 ± 187.10 μm, 729.73 ± 227.86 μm, and 661.88 ± 275.17 μm at 4 hours, 24 hours, and 1 month postsurgery, respectively. Intraoperative adjustment of ICL vault by lens rotation using intraoperative OCT was an effective procedure to obtain an optimal vault.

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

BackgroundTo newly describe the vault measurement by using a widely used swept-source OCT-based optical biometer (IOLMaster700) and accessd the accuracy of vault measurement.MethodsThis was a retrospective, cross-sectional study. All patients underwent implantable Collamer lens (ICL) implantation surgery without complications. IOLMaster700 and AS-OCT analyses were conducted for each eye on the same day in the same condition. Measurements of anterior chamber depth (ACD), corneal-ICL (C-ICL), and vault values were made and recorded. The repeatability of the IOL Master700 measurements was quantified based upon intraclass correlation coefficient (ICC) values. Correlations between IOL Master700 and AS-OCT measurements made with these different analytical approaches were assessed. The agreement of instruments was evaluated using Bland-Altman plots.ResultsThe IOLMaster700 instrument yielded highly reliable measurements of vault, C-ICL, and ACD (ICC = 0.996, 0.995, 0.995, respectively). Vault, C-ICL and ACD values as measured using the IOLMaster700, was slightly smaller than that measured via AS-OCT, but these differences were not significant (p = 0.652, p = 0.121 and p = 0.091, respectively). The vault, C-ICL, and ACD measurements by these two instruments were strongly correlated (r = 0.971, r = 0.944, and r = 0.963, respectively; all p < 0.001). The 95% limits of agreement for vault, C-ICL, and ACD measurements between the two devices were−0.08 to 0.08 mm,−0.14 to 0.11 mm, and−0.13 to 0.10 mm, respectively.ConclusionsThe IOLMasrer700 can measure implanted ICL vault with a high degree of accuracy and repeatability. Good correlations and agreement were observed between IOLMaster700 and AS-OCT in measuring vault, C-ICL, and ACD measurements.

Outcomes of the EVO ICL Using a Customized Non-horizontal or Horizontal Implanting Orientation Based on UBM Measurement: A Pilot Study.

IntroductionTo evaluate the short-term safety and efficacy of the EVO implantable collamer lens (ICL) using a customized implanting orientation design based on ultrasound biomicroscope (UBM) measurement.MethodsThe prospective case series included 310 eyes of 158 patients treated with ICL. To achieve an optimal vault, an ICL of specific size was chosen and implanted in a customized orientation according to assessment of sulcus-to-sulcus (STS) diameters, distance between STS plane and crystalline lens (STSL), the morphology of ciliary sulcus (MCS), anterior chamber depth (ACD), and white-to-white (WTW). With the new design, there were 138 eyes with a non-horizontal orientation and 172 eyes with a horizontal orientation of the ICL. Refractive and ICL vault statuses were followed up for 1 day and 1 month postoperatively.ResultsThe safety index at 1 month was 1.34 ± 0.17 for the non-horizontally implanted group and 1.33 ± 0.16 for the horizontally implanted group; the efficacy index was 1.21 ± 0.18 for the non-horizontally implanted group and 1.18 ± 0.16 for the horizontally implanted group. All eyes achieved an uncorrected distance visual acuity of 0.10 logMAR or better. No significant difference in endothelial cell density was observed between the preoperative value (2792.6 ± 247.6 cells/mm2) and value at 1 month postoperatively (2744.2 ± 243.3 cells/mm2), and no cataract or anterior subcapsular opacification was observed. Ideal vault (250–750 μm) was achieved in 84% of eyes (260/310).ConclusionThe customized ICL design of implanting orientation based on UBM measurement provides good safety, efficacy, and vault predictability.Supplementary InformationThe online version contains supplementary material available at 10.1007/s40123-022-00498-8.

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.

Three-Year Outcomes of Implantable Collamer Lens Followed by Excimer Laser Enhancement ("Bioptics") in the Treatment of High Myopic Astigmatism.

PurposeDescribe three-year outcomes of spherical implantable Collamer lens (ICL) followed by excimer laser enhancement (bioptics) in eyes with high myopic astigmatism.Patients and MethodsRetrospective case series of thirty-four cases that underwent bioptics enhancement at the Johns Hopkins Wilmer Eye Institute. All eyes had a preoperative sphere of −6.00 D or more with a cylinder of at least 2.00 D. Uncorrected and corrected distance visual acuity (UDVA and CDVA), manifest spherical equivalent refraction (MSE), ICL vault measurements and central corneal thickness (CCT) were collected. Endothelial cell counts (ECC), root mean square (RMS) of higher order aberrations (HOAs), adverse events and subsequent surgeries were also assessed.ResultsAll patients had a minimum follow-up of 3 years. Preoperative UDVA was 2.29 ± 0.46 logMAR and improved to 0.03 ± 0.23 logMAR at 3 years (p<0.05). MSE was −12.30 ± 4.05 preoperatively and changed to −0.21 ± 0.46 at 3 years (p<0.05). The efficacy and safety indices were 1.28 ± 0.32 and 1.47 ± 0.27 at 3 years post-enhancement. HOA did not significantly change throughout the follow-up (p<0.05). Endothelial cell loss at 12 months was calculated at 5.7%. Two eyes required ICL exchange due to vault-related issues.ConclusionBioptics offered excellent long-term safe, predictable, and efficient outcomes for high myopic astigmatism and can be considered an option if toric ICL is not available. Results confirm that wavefront-guided photoablation remains an excellent option to manage residual refractive error after phakic IOL.

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

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). 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. 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). 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.].

Comparison of intraoperative vs postoperative optical coherence tomography measurement of implantable collamer lens vaulting.

To compare intraoperative vs postoperative optical coherence tomography (OCT) measurements of implantable collamer lens (ICL) vaulting. American University of Beirut Medical Center, Beirut, Lebanon. Prospective observational cohort study. Patients with myopia or myopic astigmatism undergoing ICL insertion in which intraoperative OCT measurements were obtained were included. Exclusion criteria included coexisting ocular problems and previous ocular surgery. The outcome measures were ICL vaulting as determined by OCT intraoperatively and postoperatively at 1 day, 1 week, 1 month, and 3 months. Forty-five eyes of 26 patients were included. Mean age was 27.23 ± 6.47 years (range 17 to 48 years), and mean manifest refraction spherical equivalent was -10.20 ± 3.92 diopters (D) (range -20.50 to -4.50 D). Mean ICL vaulting measured 731 ± 215 μm intraoperatively, 648 ± 219 μm at 1 day, 640 ± 204 μm at 1 week, 628 ± 212 μm at 1 month, and 632 ± 210 μm at 3 months postoperatively (P = .0009, with all postoperative vaulting measurements statistically similar to each other, but significantly different from the intraoperative measurement). However, intraoperative ICL vaulting had high predictability of postoperative vaulting at 3 months with r = 0.81 (P < .0001), and Bland-Altman analysis demonstrates a relatively constant difference between the 2 measurements as plotted against their mean with a bias of 98.27 μm and tight 95% limits of agreement range. Intraoperative ICL vaulting measured by OCT correlated highly with postoperative OCT vaulting and can be considered a reliable tool to predict the final ICL vault.

Determining the Potential Role of Crystalline Lens Rise in Vaulting in Posterior Chamber Phakic Collamer Lens Surgery for Correction of Myopia.

To assess the effect of crystalline lens rise (CLR) on postoperative vault in eyes implanted with a phakic Visian Implantable Collamer Lens (ICL) (STAAR Surgical Company, Monrovia, CA) with a central port for myopic correction. Non-invasive Fourier-domain swept-source anterior segment optical coherence tomography was used for dynamic assessment of the study eyes under changing light conditions. Phakic intraocular lens (IOL) vault, anterior chamber depth (ACD), and CLR were recorded after surgery, and intra-eye differences were analyzed under scotopic and photopic ambient light conditions. Inter-group analysis and regression analysis were performed to investigate any potential correlation between these biometric variables. This retrospective observational study comprised 111 eyes (65 patients) implanted with a myopic Visian ICL. The mean change in CLR from mydriasis to miosis was 59 ± 60 µm (P < .001). The sample was further divided into four groups according to the CLR value in miosis: CLR < 0, 0 to 200, 201 to 350, and > 350 µm. A significant difference in central vault values was observed between the < 0 and > 350 µm groups, the 0 to 200 and 201 to 350 µm groups, and the 0 to 200 and > 350 µm groups (P < .05). Eyes with a high vault value (> 750 µm in mydriasis) had lower CLR values (P < .001) and higher ACD values (P < .001) than eyes with a low vault value (< 100 µm in miosis). The linear correlation observed was negative between CLR and ACD, positive between postoperative vault and ACD, and negative between postoperative vault and CLR (P < .001). CLR significantly affected anterior chamber depth and postoperative ICL vault. [J Refract Surg. 2019;35(3):177-183.].

Anterior Chamber Changes After Implantable Collamer Lens Implantation in High Myopia Using Pentacam: A Prospective Study

IntroductionThe objective of this study was to evaluate the changes of the anterior chamber (AC) of the eye after implantable Collamer lens (ICL) implantation in high myopia by using the Pentacam.MethodsThe prospective study included 34 high myopic patients (34 eyes). All patients were treated with Visian implantable Collamer lens (ICL) (Staar Surgical Co.) implantation. The Pentacam (Oculus) was used for all cases preoperatively and 1, 3 and 6 months postoperatively. AC angle (ACA), AC volume (ACV), central AC depth (CACD), ICL vault, central corneal thickness (CCT), pupil diameter (PD), K readings and intraocular pressure (IOP) were recorded.ResultsOur study included 34 eyes of 34 patients, 20 females (59%) and 14 males (41%). Mean ACA was 36.93° ± 4.75° preoperatively, 25.17° ± 5.64° and 25.23° ± 6.05° 1 and 3 months postoperatively (p < 0.001). Mean ACV was 191.24 ± 11.18 mm3 preoperatively, 141.53 ± 16.77 and 142.11 ± 15.89 mm3 1 and 3 months postoperatively (p < 0.001). Mean CACD was 3.59 ± 0.17 mm preoperatively, 2.83 ± 0.24 mm and 2.96 ± 0.25 mm 1 and 3 months postoperatively (p < 0.001). The ICL vault decreased from 0.556 ± 0.033 mm 1 month postoperatively to 0.431 ± 0.056 mm 3 months postoperatively (p < 0.001). There were no statistically significant differences for any of the AC parameters among measurements taken 3, 6 and 12 months postoperatively. There were no statistically significant differences between preoperative and any postoperative measurements of CCT, PD and K readings.ConclusionsICL implantation for correction of high myopia leads to significant changes in the anterior chamber angle, volume and depth and insignificant changes in the pupil diameter, CCT and K readings.