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RESEARCH PRODUCT

Objective assessment of cataract: Comparison between the Lens Opacities Classification System III and a Scheimpflug camera

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Purpose Develop an automatic system for cataract classification using the Sirius Scheimpflug for both nuclear and cortical cataract. Methods Scheimpflug images were taken using the Sirius system in 50 patients with nuclear and/or cortical cataract (mean age 69 ± 9.2 years). The nuclear opacity (NO) and cortical opacity was graded by an ophthalmologist according to the Lens Opacities Classification System (LOCSIII) by comparing the slit-lamp image with the LOCS's standard nuclear images. A custom-made MATLAB program was used to calculate the pixel intensity value within a region of interest (ROI) of the nucleus and to calculate the percentage of opaque pixels in the cortex. Results Eighty-nine eyes with nuclear and 81 eyes with cortical cataract were analysed. Both average and maximum NO pixel intensity units obtained from the ROI had a significant correlation with LOCS III (r = 0.731; P < 0.01 and r = 0.738; P < 0.01). The mean average NO was 21.77 ± 11.59 pixel intensity units and the mean maximum NO was 38.94 ± 18.52. A significant and positive correlation with LOCS III (r = 0.812; P < 0.01) was found when the whole cortex area was analysed. Conclusions The results from this study indicate that the Sirius Scheimpflug has a good correlation with LOCS III for lens density measurements. The use of a Scheimpflug camera might be a valuable tool in clinical practice to grade nuclear and cortical cataracts automatically and objectively.