Abstract
Purpose :
Neurodegeneration and vasculopathy are recognized pathologic processes in diabetic eyes. Decreased GC-IPL thickness in the macular OCT and altered amplitude and implicit time on full-field electrophysiologic recordings may be clinical signs that reflect the neurodegenerative process and may precede visible vascular changes. Our aim was to investigate ganglion cell function and structure across different stages of non-proliferative DR and to characterize how they relate to microvascular changes detected by OCT angiography (OCTA) in a non-selective group of diabetic patients.
Methods :
Twenty-one patients with diabetic retinopathy and sixteen age-matched controls with healthy eyes were tested for visual function (visual acuity, low contrast sensitivity, automated perimetry of central 30 degrees and full-field electrophysiology) and for retinal structure (wide-field fundus photography, OCT, OCTA). Diabetic eyes were staged from fundus photos and also ranked qualitatively by density of the superficial capillary plexus on OCT angiography.
Results :
Seven eyes had no funduscopic signs of DR. Sixteen had mild DR, eleven moderate and four severe. As a group, diabetic eyes had worse visual acuity compared to controls and showed lower mean sensitivity on visual field and contrast testing. The diabetic eyes showed longer implicit time, but not decreased amplitude of the photopic a and b wave.
All diabetic eyes showed one or more microvascular changes on OCTA. The OCTA parafoveal capillary density but not the FAZ correlated with the funduscopic grading of vascular severity. The parafoveal OCTA (qualitative rank and quantitative density) showed a significant correlation with the GCL thickness. The parafoveal capillary density was also correlated with the low contrast sensitivity, visual field mean sensitivity, and the electrophysiologic photopic negative response but not the visual acuity.
Conclusions :
Our results suggest that OCTA parafoveal capillary density is a valuable indicator of severity in both microvascular changes and neurodegenerative changes in non-proliferative diabetic retinopathy.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.