Abstract
Purpose :
To characterize the rate of microvascular changes in diabetic eyes with different diabetic retinopathy (DR) severity over time using optical coherence tomography angiography (OCT-A).
Methods :
We included diabetic subjects with at least three visits from an ongoing prospective, observational study. All the subjects underwent OCT-A with a swept-source OCT (DRI-OCT Triton, Topcon, Inc, Tokyo, Japan) in baseline and follow-up visits. Volumetric OCT scans centered on the fovea were obtained with a scan area of 3mmx3mm containing 320×320 A-scans. We customized an image analysis program for automated measurement of foveal avascular zone (FAZ) area, FAZ circularity, parafoveal vessel density (PVD) and fractal dimension (FD) from each superficial capillary plexus OCT-angiogram. DR was graded from baseline and follow-up retinal photographs using the modified Airlie House classification system. Only eyes without DR progression over the study period were included in the final analysis. The rate of change in OCT-A metrics within severity groups (no DR, mild DR and moderate or above DR) were examined with linear mixed models, adjusting for inter-eye correlation, diabetes duration, HbA1c level and LogMAR visual acuity.
Results :
Results: 100 eyes (35 no DR DR, 28 mild DR and 37 moderate or above DR) from 65 patients with diabetes were included in the final analysis. The mean follow-up period was 13.1±4.2months with a range of 10.7 to 19.8 months. There was significant rate of reduction of FD in all the severity groups (no DR, β = -0.101/year; mild DR, β = -0.093/year; moderate or above DR, β = -0.045/year, all P < 0.001). The rate of reduction of FAZ circularity was only significant in the group of moderate or above DR (β = -0.048/year, P = 0.044), but not in no DR group (β =-0.020/year, P = 0.333) and mild DR group (β = 0.005/year, P = 0.846).No Significant change over time was observed in FAZ area and PVD.
Conclusions :
OCT-A is able to detect longitudinal retinal microvascular damage (decreased complexity of microvasculature and FAZ circularity) in diabetic eyes without DR progression.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.