Abstract
Purpose :
Neuroretinopathy is increasingly being recognized as an independent cause of vision loss in diabetes. However the temporal relationship of diabetic neuroretinopathy to vascular diabetic retinopathy (DR) is unclear. Visual field loss, as detected by frequency doubling technology (FDT)-based visual perimetry, is a sign of neuroretinopathy and occurs in early stages of DR. Here, we hypothesized that FDT visual field testing could identify patients with diabetic neuroretinopathy in the absence of clinically detectable microvascular DR.
Methods :
Data were gathered from the National Health and Nutrition Examination Survey (NHANES) 2005-2008. We included all patients receiving reading center-graded two-field fundus photography and visual field screening by FDT. Patients with self-reported glaucoma, use of glaucoma medications, or determination of glaucoma based on disk features were excluded. Visual fields were screened using a FDT protocol in which participants underwent a 19 subfield suprathreshold test (N-30-5 Humphrey Matrix FDT, Zeiss). Stimuli were presented at an age-adjusted 5%, 2% and 1% probability level in a multi-staged fashion. Patients were grouped based on reading center-based DR assessment. The number of subfields below each probability level was tallied for each patient and compared among groups.
Results :
Patients with diabetes but no DR (n=530) were more likely to have ≥1subfielddefects at 5%, 2%, and 1% probability levels than patients without diabetes (n=3243) (41.3% vs 28.6%; 27.4% vs 17.5%; 15.9% vs 9.4%; all p<0.0008). Patients without diabetes had a mean of 1.9 (95% CI: 1.7, 2.2) subfield defects at the 5% probability level, while those with diabetes and no DR had a mean of 3.1 (95% CI: 2.3, 3.9) subfield defects. In participants with diabetes and no DR, a multivariate logistic regression model showed that each additional A1c percentage point was associated with a 19% increase in odds of having ≥1visual subfield defect at the 5% level (OR: 1.19, 95% CI: 1.07,1.33; p=0.0020).
Conclusions :
Patients with diabetes have visual field defectsin the absence of detectable DR, suggesting that diabetic neuroretinopathy precedes microvasculopathy. Limitations of this study include the cross-sectional nature of survey data, which lacks temporal data. Longitudinal studies are required to understand the pathogenesis of diabetic neuroretinopathy in relation to classic DR.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.