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Glenn Cockerham, Sonne Lemke, Catherine Glynn-Milley, Kimberly Cockerham; Afferent visual function in Veterans after combat blast.. Invest. Ophthalmol. Vis. Sci. 2014;55(13):166.
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© ARVO (1962-2015); The Authors (2016-present)
Evaluate patterns of deficits in Veterans with combat blast exposure and traumatic brain injury (TBI) using common measures of afferent function ; correlation of deficits between these measures; relationships between deficits and ocular injury and TBI severity; and longitudinal stability of visual function.
The study was approved by the Stanford IRB consistent with the Declaration of Helsinki. Consent was obtained for all subjects. Testing performed on Veterans with blast injury within a VA Polytrauma Rehabilitation Center included: history; complete ocular examination; and afferent testing (corrected monocular high-contrast ETDRS visual acuity (VA) , spatial contrast sensitivity (CS), and automated perimetry (30-2 SITA-STD.) Mean deviation (MD) or pattern standard deviation (PSD) were classified as moderate or severe based on age norms. Neurologic hemianopia and quadrantanopia fields were excluded from analysis. Statistical analysis included categorical variables and chi-square tests to assess relationships among visual function measures, as well as between function and ocular injury, TBI severity, and protective eyewear.
Participants were 60 men and 2 women, median age 25 years. Median time since injury was 2 months. 36 subjects were retested at a median interval of 10 months. There were 113 study eyes, after exclusion of 11 enucleated or phthisical eyes. Overall, 79% of Veterans had at least one afferent deficit (24% with VA less than 20/20; 39% with moderate to severe CS impairment versus age-norms; and 54% with moderate to severe impairment of either MD, PSD or both. A significant relationship existed between baseline and follow-up visual deficit results: VA p<.001, CS p=.04; MD p=.003, and PSD p<.001. Closed-globe injury was present in 44% of subjects and relatively evenly distributed across anatomic zones. There were significant relationships between injury and reduced VA, MD, and PSD, but not with CS. We found no relationships between visual function and TBI severity or reported usage of protective eyewear.
Using standard testing, we found significant and persistent decrements of visual performance in the majority of young Veterans after blast. Based on relationships found, we recommend spatial contrast sensitivity and perimetry testing, as well as ocular trauma evaluation, in all combatants exposed to blast, in addition to standard acuity screening.
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