Longitudinal Assessment of Ocular Biomarkers in Individuals With Gulf War Illness Symptoms

Baseline OCT measures, especially a thinner outer nasal macula, were associated with GWI symptoms. Longitudinally, individuals with GWI symptoms had greater thickening of their inferotemporal GCL compared to those without symptoms. When the model was re-examined in deployed veterans, OCT measures (at baseline and longitudinally) no longer remained significantly related with GWI symptoms and instead baseline levels of plasma inflammatory cytokine markers, IL1a and IL10, were most closely related to symptoms. Our longitudinal study builds on our previous retrospective and cross-sectional work on identifying ocular biomarkers in GWI. Across the studies, macular thinning at baseline and inferotemporal GCL-IPL thickening have been noted between cases and controls. Some of these findings share correlates with OCT biomarkers identified in conditions such as Alzheimer's, Parkinson's and Multiple Sclerosis. This is significant as it may help contextualize future research and help us develop better models of GWI.