Three-Dimensional Quantitative Description of the Implantable Collamer Lens in the Ocular Anterior Segment of Patients With Myopia.

PURPOSE: To describe the 3-dimensional (3D) location of the implantable collamer lens (ICL) quantitatively in the posterior ocular chamber of patients with myopia. DESIGN: Cross-sectional study. METHODS: To obtain visualization models before and after mydriasis, an automatic 3D imaging method based on swept-source optical coherence tomography was created. Parameters like the ICL lens volume (ILV), the tilt of the ICL and crystalline lens, the vault distribution index, and topographic maps were evaluated to describe the ICL location. Using a paired sample t test and the Wilcoxon signed rank test, the difference between nonmydriasis and postmydriasis conditions was compared. RESULTS: The study investigated 32 eyes from 20 patients. The 3D central vault did not differ significantly before (P = .994) or after mydriasis (P = .549) compared with the 2D central vault. After mydriasis, the 5-mm ILV decreased by 0.85 mm2 (P = .016), and the vault distribution index increased significantly (P = .001). The ICL and the crystalline lens exhibited tilt (nonmydriasis: ICL total tilt 3.78 ± 1.85 degrees, lens total tilt 4.03 ± 1.53 degrees; postmydriasis: ICL total tilt 3.84 ± 1.56 degrees, lens total tilt 4.09 ± 1.64 degrees). The phenomenon of asynchronous tilt of the ICL and lens was found in 5 eyes, leading to the spatially asymmetric distribution of the ICL-lens distance. CONCLUSION: The 3D imaging technique provided exhaustive and reliable data for the anterior segment. The visualization models offered multiple perspectives on the ICL in the posterior chamber. Before and after mydriasis, the intraocular ICL position was described by the 3D parameters.

The Effectiveness and Rotational Stability of Vertical Implantation of the Implantable Collamer Lens for the Treatment of Myopia.

PURPOSE: To explore the effectiveness and rotational stability of vertical implantation of the Implantable Collamer Lens (ICL) (STAAR Surgical) to treat myopia. METHODS: This was a prospective, randomized, controlled study, including 78 eyes from 46 patients with myopia who underwent ICL implantation. The patients were randomly divided into vertical and horizontal implantation groups. At 1 day, 1 week, 1 month, and 3 months after surgery, rotational stability was evaluated using the postoperative axis deviation from the intended axis by the digital anterior segment photograph. The vault, crystalline lens rise, anterior chamber depth, manifest refraction spherical equivalent, intraocular pressure, and visual acuity values were obtained before and after surgery. RESULTS: A 3-month follow-up period showed significant differences between the efficacy indexes in the horizontal (1.11 ± 0.02) and vertical (1.13 ± 0.02) groups (P = .455). No significant difference was observed in the postoperative manifest refraction spherical equivalent between the horizontal (-0.27 ± 0.18 diopters) and vertical (0.01 ± 0.08 diopters) groups (P = .151). Also, no statistically significant difference was observed in the corneal endothelial cells and intraocular pressure between groups (P = .555, P = .464). The rotation angle of the horizontal group was greater at 1 week, 1 month, and 3 months (3.14° ± 2.13°, 2.97° ± 2.01°, 3.27° ± 2.12°, respectively) compared to that of the vertical group (1.30° ± 1.29°, 1.85° ± 1.60°, 1.74° ± 1.33°, respectively) (P < .001 for all). From 1 week to 3 months, the changing angle of horizontal (0.31° ± 1.86°) and vertical (0.49° ± 1.33°) ICL rotation displayed a positive correlation with the changing vault of horizontal (48.41 ± 86.02 mm) and vertical (39.64 ± 78.43 mm) ICL rotation (r = 0.242, 0.335, P = .033, .037). CONCLUSIONS: The study supports great efficacy and safety in both vertical and horizontal implantation, with the vertical implantation group displaying better stability. [J Refract Surg. 2022;38(10):641-647.].