Discrimination between Surgical and Nonsurgical Nuclear Cataracts Based on ROC Analysis

Abstract

PURPOSE: The aim of this paper is to propose a quantitative methodology for determining a criterion to discriminate non-surgical nuclear cataract from surgical ones taking into account objective measures of intraocular scattering in patients with good visual acuity (>0.6). METHODS: Two groups of subjects were taken into account: a control group and a group with nuclear cataracts. At a first stage, eyes belonging to the cataract group were classified into non-surgical and surgical cataracts by ophthalmologists at their clinical settings. At a second stage a double pass instrument was also used to determine the Objective Scatter Index (OSI) at the laboratory. ROC curves were used to analyze OSI values to determine a value able to separate between non-surgical and surgical cataracts. RESULTS: We obtained statistically significant differences among the control and both nuclear cataract groups (p <0.05). ROC curves determined an OSI criterion level (of 2.1) to suggest surgery in nuclear cataracts with an area under curve of AUC=0.83, i.e. with 80% of sensitivity and 80% of specificity. CONCLUSIONS: ROC analysis allows separating both groups of nuclear cataract and we determined a value of OSI in nuclear cataract quantification for surgery.