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

Abstract

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.]