Detecting Visual Field Loss in Patients With Diabetes and Unapparent DR
By Lynda Seminara
Selected By: Deepak P. Edward, MD
Journal Highlights
Investigative Ophthalmology & Visual Science
2019;60(14):4711-4716
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Neuroretinopathy has been gaining recognition as an independent cause of vision loss in patients with diabetes. Bao et al. hypothesized that diabetes itself (without diabetic retinopathy [DR]) causes inner retinal visual defects, and that frequency doubling technology (FDT)–based visual perimetry can identify diabetic neuroretinopathy in the absence of clinically detectable microvascular DR. Their analysis showed that patients with diabetes may have substantial inner neuroretinopathy, even if typical microvascular lesions are not present.
For this study, data were gathered for participants of the National Health and Nutrition Examination Survey (NHANES) 2005-2008 who received fundus photography and visual field screening by FDT. Visual fields were screened in accordance with the FDT protocol, which requires a 19-subfield suprathreshold test. Patients were considered to have visual field loss if a defect was found in at least two subfields on the first and second test, and if at least one of those subfields was defective in both tests. The mean number of defective visual fields in each eye of each patient was calculated for three threshold levels: 5% or lesser, 2% or lesser, and 1%.
Of the 5,482 patients who met eligibility criteria and had gradable photos for both eyes, 1,488 were excluded due to unreliable FDT testing or their status as glaucoma suspects or glaucoma patients. The final analysis of 3,994 patients (7,988 eyes) showed that those with diabetes and no apparent DR were more likely than those without diabetes to have at least one subfield defect at the 5%, 2%, and 1% probability levels (41.3% vs. 28.6%; 27.4% vs. 17.5%; 15.9% vs. 9.4%; all p < .0008). Multivariable regression showed that each additional percentage of glycated hemoglobin denoted 19% greater odds of at least one visual subfield defect in patients with diabetes and no apparent DR.
The authors acknowledge that it isn’t clear whether diabetic neuroretinopathy and classic DR occur in parallel or sequentially. However, the data do show that inner neuroretinopathy occurs with diabetes in the absence of typical microvascular lesions.
The original article can be found here.