A study assessed two-year changes in neurodegeneration, edema, and capillary dropout in patients with non-proliferative diabetic retinopathy.
Eyes with diabetic retinopathy were evaluated using spectral domain optical coherence tomography and optical coherence tomography angiography. Examinations were performed three times at one-year intervals. Capillary dropout was determined using full retina thickness and layer-by-layer measurements, and Early Treatment Diabetic Retinopathy Study (ETDRS) classification was performed per the seven-field ETDRS protocol.
Over a two-year period, 62 eyes (62 patients) were followed; after performing image verification, final analysis included 44 eyes in 44 patients (30% were female) who were aged 52 to 80 years. Overall, 18 eyes had ETDRS grades 10 to 20, 17 had ETDRS grade 35, and nine had ETDRS grades 43 to 47. During the two-year study period, a progressive increase was observed in capillary dropout; edema and neurodegeneration remained unchanged. When adjusting for age, sex, hemoglobin A1c, visual acuity, and diabetes duration, vessel density differed largely based on Diabetic Retinopathy Severity Scale group and was correlated with disease progression.
The researchers concluded that eyes with varying disease stages with repeat visits who were followed for two years presented neurodegeneration, edema, and ischemia, which varied significantly by patient. The only factor that progressed over the study period was capillary dropout (ischemia), which was more pronounced in eyes with higher rates of reduction in vessel density.