Relation between retinal thickening and clinically visible fundus pathologies in mild nonproliferative diabetic retinopathy

BACKGROUND AND OBJECTIVE: To determine the association of retinal thickening (RT) with clinically observable retinal pathologies in eyes with mild nonproliferative diabetic retinopathy. PATIENTS AND METHODS: Using an objective quantitative imaging method (Retinal Thickness Analyzer), the ratio relative to normal RT (RTI) was measured in 23 eyes with and 35 eyes without clinically observable diabetic fundus pathology. RTI was analyzed in relation to presence of mild diabetic retinal lesions in the ±0.5 mm vicinity. RESULTS: The percent of eyes with RTI significantly above normal values did not differ significantly between eyes with and without retinopathy (30% vs 34%). Mean RTI was not associated with local presence of microaneurysms (P=0.92), soft exudates (P=0.55), or retinal hemorrhages (P=0.31). Areas without hard exudates had significantly greater mean RTI (1.10) than areas with exudates (0.97, P=0.009). CONCLUSION: In diabetic patients with mild retinopathy, areas with and without clinically observable retinal pathologies had similar retinal thickness. We conclude that clinical strategies for detection of retinal thickening should not be limited to areas with visible fundus pathologies.