Screening of positive dysphotopsia before multifocal intraocular lens implantation.

Purpose: To assess the photic phenomena (PP) and positive dysphotopsia in candidates for presbyopia or cataract surgery and to evaluate their relationship with cataract grading systems. Design: Retrospective observational. Methods: Monocular data for 82 subjects measured during the preoperative screening were retrospectively retrieved from our database. The evaluated variables consisted of two methods for PP measurement: light distortion index (LDI) and parameters obtained from a simulator, both of which were combined with subjective bother related to PP. The cutoff for LDI that better predicted patients passing from slightly to moderately bothersome was estimated. The relationships between LDI and the following objective cataract grading methods were also assessed: objective scatter index (OSI), dysfunctional lens index (DLI), and Pentacam Nucleus Staging (PNS). Results: LDI was the best method for measuring PP, which showed a significant correlation with the bothersome question (rho = 0.34, P = 0.002) and also with OSI (rho = 0.67, P < 0.0005), DLI (rho = −0.29, P = 0.007), and PNS (rho = 0.48, P < 0.0005). The number/percentage of patients who found it bothersome was as follows: "Not at all" (18/22%), "Slightly" (41/50%), "Moderately" (15/18.3%), and "Very" (8/9.7%). The cutoff value that predicted the transition from slightly to moderately bothersome was ≥15.20% according to LDI, which could be estimated with the following values for grading: ≥2.8 for OSI, ≤7.6 for DLI, and ≥2 for PNS. Conclusions: Patients reporting moderately or higher bothersome levels in the preoperative period and with LDI <15.20%, <2.8 for OSI, >7.6 for DLI, and <2 for PNS might deserve special attention in the multifocal intraocular lens selection. [ABSTRACT FROM AUTHOR]