Application of dysfunctional lens index in the diagnosis of age-related cataract and phacoemulsification

Abstract

Objective To assess the value of dysfunctional lens index (DLI) measured by iTrace visual function analyzer in the diagnosis of age-related cataract and phacoemulsification. Methods A prospective study was performed.One hundred and thirty-two cases (132 eyes) with age-related cataract were recruited from November 2016 to April 2017 in Jinan Mingshui Eye Hospital.The subjects were divided into nuclear group (39 eyes), cortical group (48 eyes) and posterior subcapsular group (45 eyes) according to the type of cataract.The preoperative best corrected distant visual acuity (LogMAR vision) were recorded.The opacification degrees of lens were determined by LOCS Ⅲ grading system.The DLI value was measured by iTrace visual function analyzer.All patients underwent traditional phacoemulsification, and cumulative dissipated energy (CDE) values were recorded.The correlation between various parameters was evaluated using Pearson correlation coefficients. Results In nuclear group, the DLI was negatively correlated with LogMAR vision, nuclear opacity (NO) scores, nuclear color (NC) scores and CDE (r=-0.593, -0.618, -0.606, -0.524; all at P<0.01). In cortical group and posterior subcapsular group, the DLI was negatively correlated with LogMAR and LOCS Ⅲ scores (cortical group: r=-0.653, -0.614; both at P<0.01; posterior subcapsular group: r=-0.583, -0.577; both at P<0.01), but no significant correlation was observed between CDE and DLI.The CDE showed an obvious positive linear correlation with LogMAR and LOCS Ⅲ scores in the 3 groups. Conclusions For different patterns of age-related cataract, the DLI shows good correlations with LogMAR and LOCS Ⅲ scores, and can reflect the degrees of visual impairment and lens opacity.The DLI can provide references for energy use in phacoemulsification of nuclear cataract. Key words: Age related cataract; Dysfunctional lens index; iTrace; LOCS Ⅲ