To assess early retinal microvascular and functional changes in diabetic patients without clinical evidence of diabetic retinopathy with optical coherence tomography angiography and central visual analyzer.
This was an observational case–control study of diabetic patients without diabetic retinopathy and nondiabetic controls. Patients underwent optical coherence tomography angiography imaging and visual acuity testing using the central visual analyzer. The foveal avascular zone area and the capillary density in the superficial and deep capillary plexuses were measured manually by a masked grader.
Sixty eyes from 35 diabetic patients were included in the study group, and 45 eyes from 31 nondiabetic patients were included in the control group. The foveal avascular zone area was not significantly different between the diabetic group and controls (both P > 0.05). The mean capillary density in the deep capillary plexus was significantly lower in diabetic eyes compared with control eyes (P = 0.04). The mean visual acuity in all central visual analyzer modules was significantly decreased in diabetic patients compared with controls (all P < 0.05).
Optical coherence tomography angiography was able to detect retinal microvascular changes in the deep capillary plexus, and the central visual analyzer showed signs of decreased visual acuity under conditions simulating suboptimal contrast and glare in diabetic patients without diabetic retinopathy.
Diabetic patients may develop an early capillary dropout at the deep capillary plexus and experience a decline in contrast sensitivity and visual acuity under glare conditions before the clinical expression of retinopathy.
*Department of Ophthalmology, Jacobs Retina Center, Shiley Eye Institute, University of California San Diego, La Jolla, California;
†Beijing Institute of Ophthalmology, Beijing Tongren Hospital, Capital Medical University, Beijing, China;
‡He Eye Hospital, He University, Shenyang, China;
§Escuela Superior de Oftalmologia, Instituto Barraquer de America, Bogota, Colombia;
¶Department of Ophthalmology, Istanbul Training and Research Hospital, Istanbul, Turkey; and
**Department of Ophthalmology, Shiley Eye Institute, University of California San Diego, La Jolla, California.
Reprint requests: William R. Freeman, MD, Department of Ophthalmology, University of California at San Diego, Shiley Eye Institute, 0946, 9415 Campus Point Drive, La Jolla, CA 92037; e-mail: email@example.com
Supported in part by UCSD Vision Research Center Core Grant P30EY022589, an unrestricted fund from Research to Prevent Blindness, NY (W.R.F). The funding organization had no role in the design or conduct of this research.
None of the authors has any financial/conflicting interests to disclose.