Abstract
Purpose :
To evaluate the integrity of radial peripapillary capillaries (RPC) of the retinal nerve fibre layer (RNFL) in different severity grades of diabetic retinopathy (DR) and examine its relationship to visual acuity (VA).
Methods :
Patients with evidence of DR were included. Optical coherence tomography angiography (OCTA) images (AngioVue, Optovue, Inc. Fremont, CA, USA) were acquired over a 3x3mm area and centered on the optic disc. RPC density were analyzed using using ImageJ with automated thresholding and presented as percentages.
Results :
86 eyes of 43 patients were included. 11 eyes (14.0%) were excluded from analysis as images were of poor quality. The mean age as 55.8 years (sd=16.6) and mean VA was 93.9 ETDRS letters (sd=13.4). 30/74 (40.5%) had mild to moderate non proliferative diabetic retinopathy (NPDR), 22/74 (29.7%) severe NPDR, 15/74 (20.3%) stable PDR, and 7/74 (9.5%) active PDR. In 61/74 (82%) maculopathy was absent, and 13/74 (17.6%) present. The mean RPC density in all patients was 28.8% (sd=4.30). Eyes with a RPC density of great or equal to 30% had a better VA (98.1 letters [sd=9.0]) compared to an RPC of less than 30% (89.7 letters [sd=16.1]) (p=0.02). RPC density was further correlated to visual acuity (r=0.34, p=0.004). No difference was observed in RPC density and retinopathy or maculopathy severity grades.
Conclusions :
OCTA has for the first time, allowed detailed analysis of the RPC in RNFL of patients with diabetic retinopathy. In a cohort of patients with established diabetic retinopathy, the relationship poor VA and low RPC density observed in this study suggests that ischemia within the papillomacular and peripapillary RNFL may be of clinical and visual significance, and warrants further investigation.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.