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Brandon Baksh, Raquel Goldhardt, Kristen Zayan, Anat Galor; Optical coherence tomography as a biomarker of Gulf War Illness. Invest. Ophthalmol. Vis. Sci. 2020;61(7):2560.
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© ARVO (1962-2015); The Authors (2016-present)
Gulf War Illness (GWI) is a multisystem disease lacking readily available, non-invasive biomarkers to assist diagnosis and stratify subpopulations. We performed a retrospective case-control study to investigate optical coherence tomography (OCT) as a biomarker to diagnose GWI and distinguish between groups within GWI.
Patients who were active duty during the Gulf War Era (GWE; 1990-91) and were seen between November 18th, 2018 and April 18th, 2019 in an optometry clinic were included. Individuals were split into two groups: those with a diagnosis of GWI and those who served during the GWE who did not meet the Kansas criteria for GWI via phone interview (controls). Of 145 GWE veterans identified, 60 met criteria for GWI and 85 were controls. 66 individuals (28 GWI and 38 controls) with available OCT data and without retinal or optic nerve disease were included in OCT analysis. OCT sub-analysis was performed on GWI veterans with and without “severely impaired cognition,” defined as ≥5 cognitive symptoms. OCT imaging included macular, ganglion cell layer-inner plexiform layer (GCL-IPL), retinal nerve fiber layer (RNFL), and optic nerve head measurements. Differences in means were analyzed using Student’s t-test or Mann-Whitney U test, as appropriate. Predictors of GWI were analyzed using forward stepwise binary logistic regression and receiver operating characteristic. All reported p-values are two-tailed, and p<0.05 was considered statistically significant.
Overall age of the population was 52.5±4.25, with 83.4% male, 39.3% White, and 22.8% Hispanic. Demographics were matched between GWI and controls. Average RNFL with and without GWI was 88.26μm±9.62 vs 91.86μm±9.50, p=0.14, with the largest difference inferiorly (6.55% decrease in GWI compared to controls, p=0.13). In a multivariable analysis, average RNFL thickness (odds ratio; OR=0.95), average cup-to-disc ratio (OR=0.005), age (OR=0.822), and post-traumatic stress disorder (OR=20.5) were significant predictors of a GWI diagnosis and explained 80% of the variability of a GWI diagnosis (area under the curve=0.8). GWI veterans with “severely impaired cognition” had significantly thinner average GCL-IPL (76.35μm±8.6 vs 84.33μm±3.01, p=0.012, a 9.5% decrease).
Our results indicate that OCT has potential as a biomarker to diagnose GWI and sub-type veterans within GWI. Longitudinal studies are needed to track progression of GWI using OCT measurements.
This is a 2020 ARVO Annual Meeting abstract.
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