Abstract
Purpose: :
The purpose of the END DR project is to identify better clinical trial endpoints for DR clinical trials that are more sensitive to early disease progression than visual acuity. A more sensitive endpoint to early disease than visual acuity will increase the feasibility of NPDR clinical trials. This abstract reports the baseline data of an ongoing 3-year natural history study of visual function in diabetics with normal fundus appearance, and NPDR patients.
Methods: :
Six aspects of visual function were measured: acuity (E-EDTRS), contrast sensitivity (Pelli-Robson), rod-mediated dark adaptation (AdaptRx), frequency doubling technology perimetry (Matrix), light-adapted visual field sensitivity (Humphrey Field Analyzer), and dark-adapted visual field sensitivity (modified Octopus 101). The FDT perimetry and light-adapted visual field used the 24-2 test pattern. OCT macular scans and 7-field stereo photographs were obtained for future grading.
Results: :
The sample consists of 24 normal adults, 33 diabetic participants, and 49 NPDR participants. At baseline, the diabetes group exhibited similar visual acuity (20/20) to the normal group (both 20/20) (p=0.74). The NPDR group exhibited a 0.1 log unit lower acuity (20/25) compared with the diabetes and normal groups (both p<0.01). The NPDR group exhibited a 0.18 log unit decrease in contrast sensitivity compared to the diabetic group (p = 0.03). Rod-mediated dark adaptation was similar for all 3 groups (p = 0.64). NPDR group exhibited a 2.3 dB reduction of the scotopic visual field (p<0.01). For FDT perimetry, the diabetes group exhibited a 2.7 dB lower mean sensitivity at the fovea (p<0.01). The NPDR group exhibited a 2.7 dB reduction in foveal sensitivity (p<0.01), and a 1.7 dB reduction in mean field sensitivity (p=0.03) compared to the diabetes group. For the light-adapted visual field, the outermost test locations mean sensitivity was depressed 1.2 dB for the diabetes group (p=0.03). The NPDR group exhibited the greatest sensitivity loss at the outermost ring (2.7 dB; p<0.01).
Conclusions: :
The NPDR group exhibited greater visual dysfunction on 4 of the 5 visual function tests compared with their baseline visual acuity reduction. For example, the NPDR group exhibited a 50% to 70% reduction in FDT foveal sensitivity which was more than twice the observed 20% reduction in acuity in comparison to the diabetes group and normal group, respectively. Participants’ vision will be assessed yearly for the next two years to evaluate the progression of the visual dysfunction observed at baseline and its relationship to disease progression.
Keywords: diabetic retinopathy • clinical (human) or epidemiologic studies: outcomes/complications • clinical (human) or epidemiologic studies: natural history