Optimization of implantable collamer lens sizing based on swept-source anterior segment optical coherence tomography

Purpose: To optimize the implantable collamer lens (ICL) sizing method using anterior segment optical coherence tomography (AS-OCT). Setting: Nagoya Eye Clinic, Nagoya, Japan. Design: Interventional case series. Methods: A stepwise multiple regression analysis was performed using the optimal ICL size as a dependent variable and preoperative AS-OCT parameters as explanatory variables for 81 eyes of 41 patients, and the NK-formula version 2 (NK-formula V2) was obtained. Thereafter, 68 eyes of 42 patients were implanted with the ICLs selected as closest to the optimal ICL size calculated by the NK-formula V2. At 3 months postoperatively, the achieved vault was measured by AS-OCT to evaluate the optimization of the sizing method. Results: The anterior chamber width (ACW) and crystalline lens rise were selected as significant parameters for the regression model (R-2 = 0.61, P < .001), as with the previous NK-formula. Of the 68 eyes, 36 patients/62 eyes (91.2%), 5 patients/5 eyes (7.3%), and 1 patient/1 eye (1.5%) were in the moderate, high, and low vault categories, respectively. In the 68 eyes, the vault showed no correlation with the optimal ICL size (R = 0.0185, P = .269), whereas the vault showed a negative correlation with the optimal ICL size in both the 12.6 mm ICL subgroup (R = -0.409, P = .0088) and the 13.2 mm ICL subgroup (R = -0.818, P = .0013). Conclusions: This optimization approach showed excellent ability to select an appropriate ICL to be implanted regardless of the value of other ocular parameters and age, except ACW. Copyright (C) 2020 Published by Wolters Kluwer on behalf of ASCRS and ESCRS