Average lens density quantification with swept-source optical coherence tomography: optimized, automated cataract grading technique

Abstract

To assess a revised version of an objective cataract grading method based on the lens densitometry on swept-source optical coherence tomography (SS-OCT) scans. Rothschild Foundation, Paris, France. Prospective case series. All patients seeking a cataract evaluation and consenting to study participation were included. Exclusion criteria were a history of ocular surgery, cornea or retina disorders, and ocular dryness. The average lens densitometry (ALD) was measured on SS-OCT scans (IOLMaster 700) using an algorithm developed with MATLAB software. The ocular scatter index (OSI), measured using a double-pass aberrometer (Optical Quality Analysis System); Pentacam nucleus staging (PNS) score; and mean PNS were also measured and compared with the ALD measurements. Two hundred eighty-five eyes (195 with cataract; 90 controls) of 155 patients aged 20 to 93years (mean 56.5years±21 [SD]) were included. The ALD measurements were repeatable (P=.99, analysis of variance). The repeatability limit was 2.50 pixel units. The ALD correlated with the OSI (r2=0.41, P<.01) and PNS score (r2=0.65, P<.01). An ALD greater than 73.8 pixel units was the cutoff threshold for cataract, with 96.2% sensitivity and 91.3% specificity. Discriminant analysis produced a model combining visual acuity and the mean ALD with an area under the receiver operating characteristic curve of 0.975 (P<.001), where the mean ALD had the highest coefficient. Using the automated algorithm based on SS-OCT ALD measurements was a repeatable, reliable objective cataract grading method. When the ALD is greater than 73.8 pixel units, it is reasonable to discuss cataract surgery in symptomatic patients.