Role of frequency doubling technology perimetry in screening of diabetic retinopathy.

Purpose: To study the ability of frequency-doubling technology perimetry (FDT) to detect sight-threatening diabetic retinopathy. Method: Fifty-eight eyes of fifty-eight patients with established diagnosis of diabetes mellitus with diabetic retinopathy, fifty-five eyes of fifty-five diabetic patients without retinopathy, and forty-one eyes of forty-one normals underwent FDT and dilated stereo-biomicroscopic fundus examination. The sensitivity and specificity of FDT in identification of "sight-threatening retinopathy" (severe and very severe nonproliferative diabetic retinopathy and proliferative diabetic retinopathy) and clinically significant macular edema (CSME) were determined. Results: For the detection of sight-threatening retinopathy, two abnormal adjacent points depressed to any level on the 20-1 screening program had a sensitivity of 90.5% and specificity of 97.6%. At (assuming a) 10% prevalence of sight-threatening retinopathy in a diabetic clinic, two abnormal adjacent points anywhere in the field depressed to any level has a positive predictive value (PPV) of 48% with a negative predictive value of 98.8%. Sensitivity and specificity for the detection of CSME was poor. Conclusions: The 20-1 screening program of the FDT is useful in the detection of sight-threatening diabetic retinopathy (PPV 48%). A normal 20-1 test rules out sight-threatening retinopathy. FDT was not useful in the detection of CSME.