Implantable Collamer Lens Size Research Articles

Effect of anterior segment structure on vault and position after implantable collamer lens implantation.

To evaluate the effect of anterior-segment structure on vault and position after implantable collamer lens (ICL) implantation using ultrasound biomicroscopy. The retrospective case-control study included insufficient vault eyes (<250 μm), ideal vault eyes (250-750 μm), and excessive vault eyes (>750 μm). The preoperative biometric parameters of the anterior-segment structure and basic data between the three groups were analyzed using one-way analysis of variance. There were significant differences (P < 0.05) between the three groups in maximum ciliary body thickness (CBTmax), iris-zonule distance (IZD), and trabecular-ciliary angle (TCA). The vault gradually decreased as CBTmax decreased and TCA increased. In the pairwise comparison, the CBTmax comparison between the insufficient vault (<250 μm) group and the excessive vault (>750 μm) group was statistically significant (P = 0.024, 95% CI: -0.17-0.017 μm); the TCA comparison between the insufficient vault (<250 μm) group and the excessive vault (>750 μm) group was statistically significant (P = 0.005, 95% CI: 1.78°-12.15°); The IZD comparison between the insufficient vault (<250 μm) group and the excessive vault (>750 μm) group was statistically significant (P = 0.037, 95% CI: 0.0027-0.1119 μm). The analysis of 284 ICL haptics locations showed that there were 16.67%, 32.69%, and 70.83% haptics located in the ciliary sulcus in three groups, respectively. The vault and ICL haptics position are related to anterior-segment structure. A thinner and posteriorly positioned ciliary body would increase the risk of low vault and fewer ICL haptics located in the ciliary sulcus after ICL implantation. This provides guidance for the selection of the ICL size and placement position before surgery.

Bibliometric and visualized analysis of posterior chamber phakic intraocular lens research between 2003 and 2023.

Myopia is causing a major public health concern, with its prevalence increasing globally. This study aimed to discuss posterior chamber phakic intraocular lens (pIOL) research publication trends and hotspots over the past 20 years. Bibliometric analysis was performed using the Web Science Core Collection to investigate posterior-chamber pIOL research publication trends. The extracted records were analyzed, and a knowledge map was built using VOSviewer v.1.6.20. The analysis included visualizing the annual publication count, countries/regions distribution, international and institutional collaborations, author productivity, and journal contribution, in addition to identifying knowledge bases and hotspots. Burst keywords were extracted using CiteSpace v.6.1.R. In total, 791 articles on posterior chamber pIOLs published between 2003 and 2023 were retrieved. China had the highest number of publications, whereas Japanese papers received the most citations. Fudan University had the highest number of publications, with articles from Kitasato University having the highest number of citations. Regarding individual research, Xingtao Zhou has published the most significant number of articles, and Shimizu Kimiya had the highest number of citations. The top productive/influential journal was 'Journal of Cataract & Refractive Surgery'. The top cited references primarily focused on reporting the clinical outcomes of implantable collamer lens (ICL) for individuals with moderate to high myopia. The keywords primarily formed four clusters: posterior chamber pIOL clinical outcomes for myopic astigmatism correction, posterior chamber pIOL implantation complications, ICL size selection and postoperative vault predictions, and postoperative visual quality following posterior chamber pIOL implantation. This study presents the first bibliometric analysis of research trends in posterior chamber pIOL over the past two decades. We investigated the current state and emerging trends of global collaboration and research focal points in this field, offering fresh insights and guidance for researchers.

Enhancing Vault Prediction and ICL Sizing Through Advanced Machine Learning Models.

To use artificial intelligence (AI) technology to accurately predict vault and Implantable Collamer Lens (ICL) size. The methodology focused on enhancing predictive capabilities through the fusion of machine-learning algorithms. Specifically, AdaBoost, Random Forest, Decision Tree, Support Vector Regression, LightGBM, and XGBoost were integrated into a majority-vote model. The performance of each model was evaluated using appropriate metrics such as accuracy, precision, F1-score, and area under the curve (AUC). The majority-vote model exhibited the highest performance among the classification models, with an accuracy of 81.9% area under the curve (AUC) of 0.807. Notably, LightGBM (accuracy = 0.788, AUC = 0.803) and XGBoost (ACC = 0.790, AUC = 0.801) demonstrated competitive results. For the ICL size prediction, the Random Forest model achieved an impressive accuracy of 85.3% (AUC = 0.973), whereas XG-Boost (accuracy = 0.834, AUC = 0.961) and LightGBM (accuracy = 0.816, AUC = 0.961) maintained their compatibility. This study highlights the potential of diverse machine learning algorithms to enhance postoperative vault and ICL size prediction, ultimately contributing to the safety of ICL implantation procedures. Furthermore, the introduction of the novel majority-vote model demonstrates its capability to combine the advantages of multiple models, yielding superior accuracy. Importantly, this study will empower ophthalmologists to use a precise tool for vault prediction, facilitating informed ICL size selection in clinical practice. [J Refract Surg. 2024;40(3):e126-e132.].

Utilization of the Reinstein ICL Sizing Formula With Hand-held Ultrasound Biomicroscopy Measurements.

To evaluate the accuracy of the Reinstein formula with hand-held ultrasound biomicroscopy (UBM) measurements for sizing of the Implantable Collamer Lens (ICL). A total of 107 myopic eyes of 57 patients implanted with the ICL were included in the study. The size of the ICL was selected based on the manufacturer's recommendations. Agreement between the vault predicted by the Reinstein formula and the vault measured postoperatively was analyzed with Bland-Altman plots. A total of 95% and 81% of patients had a postoperative vault ranging from 150 to 1,000 and 250 to 750 μm, respectively. The mean vault predicted by the Reinstein formula and the postoperative vault in the current study were 580 ± 181 and 547 ± 200 μm, respectively. The size recommendations of the Reinstein formula and the formula provided by the manufacturer, the Kojima formula, and the Dougherty formula overlapped in 50%, 57%, and 49% of eyes, respectively. The results show that the Reinstein formula combined with a hand-held UBM provides reliable sizing predictions of the ICL. However, considering that robotic UBM measurements have demonstrated a narrower range of deviation in predicting vault depth in previous studies, a direct comparison study between robotic UBM and hand-held UBM measurements is necessary to fully assess the limitations of combining hand-held UBM with the Reinstein formula. [J Refract Surg. 2024;40(3):e142-e147.].

Clinical decision support system based on deep learning for evaluating implantable collamer lens size and vault after implantable collamer lens surgery: a retrospective study

ObjectivesTo aid doctors in selecting the optimal preoperative implantable collamer lens (ICL) size and to enhance the safety and surgical outcomes of ICL procedures, a clinical decision support system (CDSS)...

Comparative evaluation of multiple nomograms for predicting postoperative vault after implantable collamer lens surgery.

To compare the vault predictability of most available implantable collamer lens (ICL) sizing nomograms and identify which preoperative measurements are predictive of vault. Private practice in Draper, Utah. Retrospective chart review. This study was a retrospective analysis of 209 eyes of 106 patients who underwent STAAR Surgical ICL implantation. Analyses were performed based on the availability of preoperative parameters, varying the number of eyes for each test. Mean absolute error (MAE) of predicted vs actual postoperative vault was calculated for each nomogram. The frequency of Kim, Rocamora (least absolute shrinkage and selection operator-optical coherence tomography), Russo, and Reinstein recommending the correct ICL size in instances when Parkhurst, optimized white-to-white (WTW), and STAAR could not recommend a definitive ICL size was determined. Univariate and multivariate linear regression analysis was performed between preoperative measurements and vault. The Kim, Rocamora, Russo, and Reinstein nomograms had significantly lower MAE of predicted vs actual postoperative vault than the KSV2 and Nakamura V3 nomograms. The Russo formula most frequently recommended the correct ICL size when the Parkhurst, Optimized WTW, and STAAR nomograms could not provide ICL size recommendations. At the 0.05 significance level, anterior chamber depth (ACD), ciliary body inner diameter (CBID), and pupil diameter were the parameters found to have significant correlation with postoperative vault. The Kim, Rocamora, Russo, and Reinstein nomograms were the most predictive of vault. Additionally, ACD, CBID, and pupil diameter were found to be significantly correlated with vault and should be considered for use in future ICL sizing nomograms.

A Comprehensive Retrospective Analysis of EVO/EVO+ Implantable Collamer Lens: Evaluating Refractive Outcomes in the Largest Single Center Study of ICL Patients in the United States.

We evaluate visual outcomes in patients with EVO/EVO+™ (posterior chamber phakic intraocular lens with a central port) within approved United States (US) age and refractive range indications. This single-center retrospective study evaluated one-month, single-center postoperative data for 225 eyes meeting inclusion criteria and undergoing EVO/EVO+ implantation from April to October 2022. Data included lens size (mm), lens power (diopters of spherical and cylindrical power), preoperative best corrected visual acuity, preoperative spherical equivalent from manifest refraction, achieved postoperative uncorrected visual acuity, postoperative refraction, intraocular pressure (mmHg), and adverse events. A total of 225 eyes underwent EVO/EVO+ Implantable Collamer Lens (ICL) implantation from April to October 2022, with 51.5% receiving toric lenses. The most common ICL size was 12.6mm (56.4%), followed by 13.2mm (27.5%), 12.1mm (15.1%), and 13.7mm (0.9%). Among patients with preoperative BCVA of 20/20 or better (149 eyes), 95.2% achieved postoperative UCVA of 20/20 or better, and 99.3% achieved UCVA of 20/25 or better at postoperative month one. About 75% of eyes were within a spherical equivalent target of ±0.50 D and 94% within ±1.00 D. Toric ICLs were implanted in 116 eyes (51.8%). Of these, anticipated residual cylinder >1 diopter was seen in 21 eyes (18.1%) resulting in three rotations, three explants, and three laser vision correction (LVC) enhancements. The postoperative adjustment rate (including rotations, exchanges, and LVC enhancement) was minimal (4.8%). Incidence of major adverse events was 0%. Our study, the largest US single-center analysis of EVO/EVO+ ICL implantation, demonstrates strong early results and infrequent adverse events, supporting ICL safety and effectiveness. High predictability and favorable visual outcomes, including 20/20 or better, highlight the reliability of this technology. Despite study limitations, our findings underscore this technology's effectiveness. Future research should refine patient criteria and assess long-term outcomes in this evolving landscape.

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.

Development and Validation of Data-Level Innovation Data-Balancing Machine Learning Models for Predicting Optimal Implantable Collamer Lens Size and Postoperative Vault.

There are only four sizes of implantable collamer lens (ICL) available for selection, which cannot completely fit all patients as a result of the discontinuity of ICL sizes. Sizing an optimal ICL and predicting postoperative vault are still unresolved problems. This study aimed to develop and validate innovative data-level data-balancing machine learning-based models for predicting ICL size and postoperative vault. The patients were randomly assigned to training and internal validation sets in a 4:1 ratio. Feature selection was performed using analysis of variance (ANOVA) and Kruskal-Wallis feature importance methods. Traditional linear regression model and machine learning-based models were used. The accuracy of models was assessed using the area under the curve (AUC) and confusion matrix. A total of 564 patients (1127 eyes) were eligible for this study, consisting of 808 eyes in the training set, 202 eyes in the internal validation set, and 117 eyes in the external validation set. Compared with the traditional linear regression method, the machine learning model bagging tree showed the best performance for ICL size selection, with an accuracy of 84.5% (95% confidence interval (CI) 83.2-85.8%), and the AUC ranged from 0.88 to 0.99; the prediction accuracy of 12.1mm and 13.7mm ICL sizes was improved by 49% and 59%, respectively. The bagging tree model achieved the best accuracy [90.2%, (95%CI 88.9-91.5%)] for predicting the postoperative vault, and the AUC ranged from 0.90 to 0.94. The prediction accuracies of internal and external validation dataset for ICL sizing were 82.2% (95%CI 81.1-83.3%) and 82.1% (95%CI 81.1-83.1%), respectively. The innovative data-level data balancing-based machine learning model can be used to predict ICL size and postoperative vault more accurately, which can assist surgeons in choosing optimal ICL size, thus reducing risks of postoperative complications and secondary surgery.

Vault predicting after implantable collamer lens implantation using random forest network based on different features in ultrasound biomicroscopy images.

To analyze ultrasound biomicroscopy (UBM) images using random forest network to find new features to make predictions about vault after implantable collamer lens (ICL) implantation. A total of 450 UBM images were collected from the Lixiang Eye Hospital to provide the patient's preoperative parameters as well as the vault of the ICL after implantation. The vault was set as the prediction target, and the input elements were mainly ciliary sulcus shape parameters, which included 6 angular parameters, 2 area parameters, and 2 parameters, distance between ciliary sulci, and anterior chamber height. A random forest regression model was applied to predict the vault, with the number of base estimators (n_estimators) of 2000, the maximum tree depth (max_depth) of 17, the number of tree features (max_features) of Auto, and the random state (random_state) of 40.0. Among the parameters selected in this study, the distance between ciliary sulci had a greater importance proportion, reaching 52% before parameter optimization is performed, and other features had less influence, with an importance proportion of about 5%. The importance of the distance between the ciliary sulci increased to 53% after parameter optimization, and the importance of angle 3 and area 1 increased to 5% and 8% respectively, while the importance of the other parameters remained unchanged, and the distance between the ciliary sulci was considered the most important feature. Other features, although they accounted for a relatively small proportion, also had an impact on the vault prediction. After parameter optimization, the best prediction results were obtained, with a predicted mean value of 763.688 µm and an actual mean value of 776.9304 µm. The R2 was 0.4456 and the root mean square error was 201.5166. A study based on UBM images using random forest network can be performed for prediction of the vault after ICL implantation and can provide some reference for ICL size selection.

Efficacy and Safety of Implantable Collamer Lens V4c Implantation in 1,834 Myopic Eyes for 1 Year of Follow-up.

To evaluate visual outcomes of patients with myopia after EVO Implantable Collamer Lens (ICL) (STAAR Surgical) implantation and predict risk factors of postoperative vault abnormalities. In this single-center, retrospective analysis, 1,834 eyes of 926 patients with myopia who underwent EVO ICL implantation were recruited between 2020 and 2021. Patients were followed up for 1 year, during which surgery outcomes were evaluated. In addition, 31 eyes with vault abnormalities who underwent secondary surgery were enrolled to form a generalized linear model, which aimed to predict risk factors contributing to vault abnormalities. At the final follow-up visit, safety and efficacy indexes were 1.12 ± 0.17 and 1.10 ± 0.19, respectively, and there was no statistical significance between the low and high myopia groups. Furthermore, 79.18% of eyes achieved a residual spherical equivalent within ±0.50 diopters. Except for the temporary elevation of intraocular pressure at 1 week postoperatively, IOP and endothelial cell density remained stable during follow-up visits. The rate of postoperative adverse events was 21.97% and most adverse events were transient. Vault abnormalities accounted for the majority of complications (9.54%). Results of generalized linear model showed that age was a risk factor for postoperative vault abnormalities, and the anterior chamber depth served as a protective factor (P < .05). Visual outcomes of EVO ICL implantation were satisfactory in safety and efficacy indexes in both the low and high myopia groups for 1 year of follow-up, with acceptable stability in postoperative spherical equivalent, intraocular pressure, and endothelial cell density. This study emphasized cautious ICL size selection for older patients and those with shallow anterior chamber depth. [J Refract Surg. 2023;39(10):694-704.].

Comparison of a new implantable collamer lens formula to standards formulas using spectral domain optical coherence tomography.

To use spectral-domain optical coherence tomography (SD-OCT) data to develop a new implantable collamer lens (ICL) sizing formula and compare vault outcomes with the Online Calculation and Ordering System™ (OCOS) and the NK2 formula. Consecutive eyes (n = 237) were evaluated that had undergone ICL/toric ICL implantation. Actual ICL vaults were measured, and a what-if analysis was performed to predict vault values with the NK2 formula using SD-OCT data. To develop a new formula (EPB), multiple regression analysis was performed with different parameters than the NK2 formula. Predicted vaults with NK2 and EPB formulas were compared to the actual vaults. Parameters that were correlated with optimal ICL size were white-to-white, anterior chamber width, lens rise and desired refractive correction. The mean postoperative vault was 489 ± 258μm. At last visit, 94.5% of eyes were within the manufacturer's acceptable vault range. Predicted vaults in the acceptable range were 74 and 87% with the NK2 and EPB formulas, respectively. Six percent had a predicted vault less than 100μm with the EPB formula compared to 1% for actual outcomes. The NK2 formula resulted in a shift toward higher predicted vaults while the EPB formula was similar to the actual postoperative vaults but with slightly more cases with extremely low and high vaults. SD-OCT data with OCOS result in good postoperative vaults. Further refinement is required to the NK2 for use with SD-OCT data. Although the EPB formula provides acceptable predicted vaults, further refinement with a larger sample size is needed.

A new formula based on new parameters for predicting postoperative vault after posterior chamber intraocular lens implantation: a retrospective study.

To investigate the parameters influencing vault after posterior chamber intraocular lens implantation, thereby establishing a formula to predict the vault after operation. In this retrospective study, 61 patients (122 eyes) who underwent implantable collamer lens (ICL) implantation were enrolled consecutively from the Qingdao Eye Hospital of Shandong First Medical University, China, between August 2020 and October 2021. Comprehensive optometry, axial length, curvature, anterior chamber depth (ACD), lens thickness (LT), white-to-white distance (WTW), corneal thickness, sulcus-to-sulcus distance (STS), the distance between the sulcus-to-sulcus plane and the anterior crystalline lens surface (STSL), ciliary-to-ciliary distance (CTC) and the distance between the ciliary-to-ciliary plane and the anterior crystalline lens surface (CTCL) were recorded preoperatively. The vault was measured by ultrasound biomicroscopy at 1 month after operation. The correlation among vault, preoperative parameters and ICL size was analyzed. The accuracy and reliability of the prediction formula were verified by analyzing the postoperative correlation coefficient of actual and predicted vaults of the contralateral eye and through the Bland-Altman consistency test. Parameters significantly influencing the vault at 1 month after operation are ACD (r=0.260, P=0.004), LT (r=-0.338, P<0.001), WTW (r=0.240, P=0.03), STSL (r=-0.394, P<0.001), CTC (r=-0.199, P=0.03), CTCL (r=-0.328, P<0.001), ICL size (r=0.224, P=0.01) and ICL power (r=-0.231, P=0.01). The regression formula was as follows: vault (mm) = -2.179 - 0.227 * CTC (vertical) - 0.783 * CTCL (mean) + 0.472 * ICL size (fitting R=0.853, R2=0.727, adjusted R2=0.705). The predicted vault was 0.50±0.18 mm, and the actual vault was 0.56±0.24 mm. The Bland-Altman scatter plot showed a satisfactory agreement between actual and predicted vaults (-0.06 mm, 95% limits of agreement: -0.45 to 0.32 mm). ACD, LT, WTW, STSL, CTC, CTCL, ICL size and ICL power were the factors affecting vault after ICL implantation. The prediction formula with the new parameter CTCL was accurate and reliable.

A vault-prediction formula for implantable collamer lens based on preoperative parameters: a retrospective clinical study

ObjectivesThe aim of the present study was to predict the vault of implantable collamer lens (ICL) using a formula established based on the preoperative parameters.MethodsThis retrospective study included data on 226 eyes from 114 patients(the median age and range was 27.5 ± 5.7; 18–46 years) who underwent EVO-ICL surgery between May 2021 and April 2022. Preoperative parameters, such as anterior chamber depth (ACD) horizontal angle-to-angle diameter (ATA), Crystalline lens rise (CLR), and vault (1 week after surgery) were measured by anterior segment optical coherence tomography. The axial length of eyes (AL) and white-to-white (WTW) values were measured using an IOLmaster and calipers under a slit lamp separately.ResultThe mean WTW, ACD, horizontal ATA diameter, CLR, AL, and vault 1 week after surgery were 11.42 ± 0.37 mm, 3.25 ± 0.25 mm, 11.72 ± 0.44 mm, 45.78 ± 175.42 μm, 27.61 ± 1.93 mm, and 586.51 ± 254.54 μm respectively. Multivariate regression analysis showed that the ICL-width, ACD (β = 0.293), ATA (β =-0.657), CLR (β =-0.157), and the anterior chamber angle in temporal side (T:ACA) (β=-0.277) were predictors of the vault size (adjusted-R2 = 0.39, P < 0.001).ConclusionThe formula built based on these preoperative parameters could be used to predict the vault before surgery. The predictors indicated that the pre-operative parameters of eye such as ACD, ATA, CLR and T:ACA play an important role in choosing optimal ICL size.

Analysis of Inter-Eye Vault Differences After Implantable Collamer Lens (V4c) Implantation.

The safety and stability of implantable collamer lens (ICL) implantation are closely related to the vault. We aimed to assess clinical data from patients with similar anterior segment anatomy who received ICL of the same model placed in the same position and analyze common range and factors affecting the vault inter-eye difference. A prospective study was performed, including 162 eyes of 81 patients with a bilateral ICL (V4c) implantation. Subjects were evaluated before the surgery and 1 day, 1 week, and 1 month postoperatively, and they were divided into 4 groups based on the ICL size. Bivariate correlation and multiple linear regression (stepwise) analyzed associations between vault inter-eye differences and horizontal sulcus-to-sulcus diameter, anterior chamber depth, lens thickness, ICL size, spherical equivalent, and vault. One month after surgery, mean vault inter-eye differences were 74.59 ± 55.59 µm. Nearly 70% of patients presented with vault inter-eye differences lower than 100 µm. The second eye vault variance of 69% was attributed to the first eye vault. Vault inter-eye differences were positively correlated with ICL spherical equivalent (regression equation: vault inter-eye differences (μm) = 139.415 + 6.295 × ICL spherical equivalent). Vaults after ICL implantation were similar in fellow eyes, with some considerable differences. The 95% confidence interval of the vault inter-eye difference was -34.4 ~ 183.6 μm. In eyes with similar anterior segment anatomy, there is a 95% probability that the vault will vary from -34.4 μm to -183.6 μm when a similar ICL is implanted. These results can help surgeons to select an appropriate ICL size to achieve an ideal vault. The smaller the spherical equivalent, the larger the difference between the two vaults, which provides a reference for size in moderate myopia. ICL spherical equivalent affects and predicts vault inter-eye differences after ICL implantation.

Efficacy of Biometry Using Swept-source Optical Coherence Tomography for Posterior Chamber Phakic Intraocular Lens Implantation

Purpose: The proper implantable collamer lens (ICL) size affects ICL stability. This study compared device efficacy using white-to-white diameter (WTW) measurements with Orbscan II and IOL Master 700.Methods: We retrospectively studied 90 eyes (45 patients) who underwent toric ICL implantation from January 2019 to February 2020 and were followed for 1 year. The correlation between WTW and anterior chamber depth (ACD) for each measuring device was analyzed.Results: The mean WTW measured by IOL Master 700 and Orbscan II was 12.2 ± 0.3 and 11.6 ± 0.3 mm, respectively, while the mean ACD was 3.28 ± 0.16 and 3.20 ± 0.15 mm. The WTW and ACD measured with IOL Master 700 averaged 0.57 ± 0.12 and 0.08 ± 0.04 mm larger than with Orbscan II. The differences were significant and the regression analysis had high correlations (R&lt;sup&gt;2&lt;/sup&gt; = 0.875 and R&lt;sup&gt;2&lt;/sup&gt; = 0.913, respectively; both &lt;i&gt;p&lt;/i&gt; &lt; 0.001).Conclusions: WTW measured by the IOL Master 700 can be used as a reference either alone or together with the Orbscan II value to determine ICL size.

Evaluation of Ocular Diameter Parameters Using Swept-Source Optical Coherence Tomography.

Purpose: To investigate the iridocorneal angle-to-angle (ATA), sclera spur-to-sclera spur (STS), and white-to-white (WTW) ocular diameters and their potential influence on anterior chamber intraocular lens (ACIOL) and implantable collamer lens (ICL) sizing in Chinese subjects by using a swept-source optical coherence tomography system (SS-OCT). Design: A retrospective, observational, cross-sectional study. Methods: In 60 right eyes (60 subjects), the ATA, STS, and WTW were measured in six axes (0°-180°, 30°-210°, 60°-240°, 90°-270°, 120°-300°, and 150°-330°) using SS-OCT. The ACIOL and ICL sizes were calculated based on horizontal and vertical axes anterior segment data. A paired sample t-test was used to test the differences in each parameter across the six axes, the potential difference between each pair of parameters in a given axis, and the artificial lens size difference between the horizontal and vertical directions. Pearson's correlation analysis was used to determine the potential correlation between age and AL, WTW, STS, and ATA distances. Results: ATA and STS were the longest on the vertical and shortest on the horizontal axis, while WTW was similar on both axes. These three parameters differed only in the vertical axis (F = 4.910, p = 0.008). ATA and STS were by 0.23 ± 0.08 mm (p = 0.005) and 0.21 ± 0.08 mm wider (p = 0.010) than WTW, respectively. ICL size was 0.27 ± 0.23 mm smaller when based on the horizontal than on the vertical axis parameters (p < 0.001), while ACIOL remained similar (p = 0.709). Age correlated negatively and axial length positively with all measured values. ATA, STS, and WTW correlated positively in the same axis (all p < 0.001). Conclusions: ATA and STS were longer in the vertical than in the horizontal direction, while WTW measurements remained similar. ATA and STS diameters more accurately depicted anatomic relationships for phakic IOL sizing than WTW.

Evaluation of Implantable Collamer Lens Sizing Developed by Reviewing the Horizontal Compression-vault Coefficient.

To evaluate the implantable collamer lens (ICL) sizing method using the partial regression coefficient of the implanted ICL size to review the conventional horizontal compression coefficient and match the results of clinical observation. Nagoya Eye Clinic, Nagoya, Japan. Interventional case series. Patients who underwent ICL V4c implantation to correct myopia and myopic astigmatism were enrolled. The stepwise multiple regression analysis used achieved vault as a dependent variable and preoperative biometric parameters as explanatory variables. The partial regression coefficient of the implanted ICL size was obtained to develop the optimal ICL-sizing formula, the NK-formula version 3 (NK-formula V3). Eighty-five eyes of 45 patients were implanted with an ICL size recommended by the NK-formula V3. At 3 months postoperatively, the achieved vault was measured using AS-OCT to validate the NK-formula V3. The study enrolled 174 patients (174 eyes). The partial regression coefficient of the implanted ICL size adopted as the compression-vault coefficient in the multiple regression equation predicting the vault was 0.729. To validate the NK-formula V3, 77 (90.6%), seven (8.2%), and one (1.2%) eye were in the moderate, low, and high vault categories, respectively. The mean difference between the achieved and predicted vault was 0.064±0.190 (range: -0.264-0.742) mm for the NK-formula V3 and 0.176±0.217 (range: -0.254-0.907) mm for the NK-formula V2. As in vivo coefficient measurement experiments are not possible, the partial regression coefficient is the best option for developing a formula to predict the optimal ICL size.

Improvement in the ideal range of vault after implantable collamer lens implantation: a new vault prediction formula.

To derive and validate a novel vault prediction formula to improve the predictability and safety of implantable collamer lens (ICL) implantation. Thirty-five patients (61 eyes) with previous posterior chamber intraocular lens implantation were included. Various parameters, such as horizontal-visible iris diameter (HVID), photopic pupil diameter (PPD), axial length (AL), white-to-white (WTW), anterior chamber width (ACW), angle-to-angle (ATA), crystalline lens rise (CLR), anterior chamber depth (ACD), horizontal sulcus-to-sulcus (HSTS), and ciliary sulcus angle (CSA) were measured. Vault was measured at 3 months after surgery using CASIA2 anterior segment optical coherence tomography. The formula was derived using multiple linear regression analysis and named as WH formula. It was validated in 65 patients (118 eyes) to determine the percentage of the ideal postoperative vault range and to compare the differences between the WH formula and the NK, KS, and STAAR formulas. Final ICL size, ATA, CSA, and CLR were included in the prediction formula model (adjusted R2 = 0.67, p < 0.001). The achieved vault 1 month after the surgery was 556.19 μm ± 166.98 μm in the validation group, and the ideal vault range was 200-800 μm (92%). The difference between the achieved vault and that predicted using the WH formula was not statistically significant (p = 0.165), whereas the difference between the achieved vault and that predicted using the NK and KS formulas was statistically significant (p < 0.001 and p < 0.001, respectively). The 95% agreement limit range of the achieved vault and the vault predicted using the WH formula was narrower than those predicted using the NK and KS formulas (-295.20-258.82 μm). This study combined the results of optical coherence tomography and ultrasound biomicroscopy measurements of the anterior segment of the eye and incorporated ciliary sulcus morphology quantification into the prediction formula. The study derived a prediction formula for vault by combining ICL size, ATA, and CLR. The derived formula was found to be superior to the currently available formulas.