Ocular manifestations and biomarkers of Gulf War Illness in US veterans

Abstract

Gulf War Illness (GWI) is a multisystem disease with variable presentations, making diagnosis difficult. Non-invasive biomarkers would aid in disease diagnosis. We hypothesized that the eye could serve as a biomarker for GWI. We performed a retrospective case–control study using a sample of 1246 patients seen during a 5-month period in an optometry clinic. We identified veterans who were active duty during the Gulf War Era and either had a questionnaire-based diagnosis of GWI (cases) or did not (controls). Medical records were reviewed for eye and medical co-morbidities, medication use, and retinal macular and nerve fiber layer (NFL) thicknesses based on optical coherence tomography (OCT) images. Compared to controls (n = 85), individuals with GWI (n = 60) had a higher frequency of dry eye symptoms (50% vs 32.9%, p = 0.039). Multivariable analysis revealed average retinal NFL thickness (odds ratio; OR = 0.95), cup-to-disc ratio (OR = 0.005), age (OR = 0.82), and PTSD (OR = 20.5) were predictors of a GWI diagnosis. We conclude that GWI is associated with dry eye symptoms and RNFL thinning may serve as a biomarker for disease.

Pyridostigmine Bromide Pills and Pesticides Exposure as Risk Factors for Eye Disease in Gulf War Veterans

“…It is possible that similar processes also occur in the retina and can be detected by SD-OCT. It is important to note, however, that in a prior study, we found that RNFL measures were thinner in deployed GW veterans with GWI symptoms versus controls (deployed without symptoms or not deployed), with a mean 6.55% decrease in inferior RNFL thickness [ 14 ]. We hypothesize that exposures in the GW arena may have both neuroinflammatory and neurodegenerative consequences, which could present as thickening or thinning in RNFL and/or macular metrics and that the contribution of these two processes may change SD-OCT measures over time.…”

“…Specifically, Ocular Surface Disease Index (OSDI) scores were significantly higher in veterans with GWI symptoms (n = 30) versus controls (n = 41) (41.20 ± 22.92 vs. 27.99 ± 24.03, p = 0.01) [ 13 ]. In addition to DE symptoms, retinal nerve fiber layer (RNFL) thinning has been noted in deployed GW veterans with GWI symptoms (n = 28) versus controls (n = 38), with the largest difference seen in the inferior RNFL (109.33 ± 26.20 μm vs. 117.00 ± 24.29 μm, p = 0.13) [ 14 ]. All of these findings point to the potential impact of war time exposures on eye health.…”