Alterations of the blood-retinal barrier and retinal thickness in preclinical retinopathy in subjects with type 2 diabetes

OBJECTIVE: To identify alterations of the blood-retinal barrier by mapping retinal fluorescein leakage into the vitreous and changes in retinal thickness occurring in the macular region in preclinical diabetic retinopathy. METHODS: Ten eyes from 10 patients with type 2 diabetes and no lesions visible on fundus photography (level 10 of Wisconsin grading) were examined with the retinal leakage analyzer (RLA) (Confocal Scanning Laser Ophthalmoscope [modified]; Carl Zeiss Inc, Thornwood, NY) and the retinal thickness analyzer (RTA) (Talia Technology, Mevaseret Zion, Israel). The maps of retinal leakage and retinal thickness were aligned and integrated in the same image to correlate leakage with thickness. Data from the group of individuals with diabetes were compared with those of a healthy control population (N = 14; mean age, 48 years; range, 42-55 years) and used to establish reference maps for the RLA and RTA. RESULTS: Areas of abnormally increased fluorescein leakage were detected in 9 of 10 eyes examined. The increased leakage in 6 (67%) of 9 eyes reached values higher than 40% more than the mean +2 SD RLA control value. Areas of abnormally increased thickness were found in 7 of 10 eyes examined. For the most part, the increases in retinal thickness were not severe (ie,