Visual Acuity Improvement in Low, Moderate and High Myopia After Posterior-Chamber Phakic Implantable Collamer Lens Surgery in a Large Patient Cohort.

Purpose: To compare best-corrected visual acuity (BCVA) before and after implantable collamer lens (ICL) surgery in patients with low, moderate and high myopia. Methods: A single-centre, prospective, registry-based study involving patients with myopia who received ICLs between October 2018 and August 2020. The study population was divided into three groups of subjects with low (from 0 to -6 D), moderate (-6 to -10 D) and high myopia (more than -10 D). We analysed uncorrected visual acuity (UCVA), best-corrected visual acuity (BCVA), spherical equivalent (SE), differences between BCVA pre- and 1-month postoperative, and line gain in BCVA 1 month after surgery. Results: A total of 770 eyes belonging to 473 patients were surgically intervened during the study period, of which 692 eyes completed 1 month of postoperative follow-up and were included in the study population. At 1-month follow-up, 478 eyes (69%) achieved a BCVA of 20/20, 599 (87%) obtained 20/25 or better, and 663 (96%) had a BCVA of 20/40 or better. We identified a significant improvement in BCVA (baseline 0.15±0.2 logMAR vs follow-up 0.07±0.2 logMAR, p<0.0001) and a significant reduction in SE (baseline -9.23±4.1 D, vs follow-up -0.21±0.8 D, p<0.0001), with a significant relationship between preoperative SE and line gain (r = -0.46, p<0.0001). We identified a significantly higher line gain among eyes with higher degrees of myopia (low myopia 0.22±0.69 lines compared to moderate myopia 0.56±1.1 lines and high myopia 1.51±1.9 lines, p<0.0001). Notably, 99.6% of eyes with a high grade of myopia achieved improvement to a low degree (less than -6 D) at follow-up. The safety and efficacy indexes were 0.083±0.1 and -0.001±0.1, respectively. Conclusion: In this large patient cohort, ICL surgery was related to a significant line gain in BCVA, particularly among eyes with higher degrees of myopia.

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

Purpose: To assess the position of the haptics of the implantable collamer lens (ICL) in myopic eyes using a high-frequency ultrasound robotic scanner. Methods: 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. Results: 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). Conclusion: 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.

PURPOSE: 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. SETTING: Instituto Zaldivar SA. Mendoza, Argentina. DESIGN: Prospective single-arm observational study. METHODS: 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. RESULTS: 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. CONCLUSIONS: Intraoperative adjustment of ICL vault by lens rotation using intraoperative OCT was an effective procedure to obtain an optimal vault.

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.].