Abstract
Purpose:
Traumatic brain injury (TBI), a major cause of death and disability worldwide can lead to vision damage. The extent of subjective visual dysfunction present in combat veterans with mild TBI is still unknown. The purpose of this study is to evaluate subjective vision-related complaints, visual field deficit and retinal nerve fiber layer (RNFL) thickness in Servicemembers with documented mild TBI due to blast and/or blunt trauma. It is hypothesized that visual/ocular symptomology and measures will be similar between the groups.
Methods:
90 patients with documented mild TBI were evaluated. All patients underwent symptom review and detailed ophthalmic examination, including visual acuity (VA). 87 patients had visual field testing (HVF) in both eyes, 75 had SD-OCT in at least one eye and 49 had contrast sensitivity (CS) tested in both eyes. Based on the history of head trauma, patients were divided into three groups: Group 1 (Gr1) blast only, Group 2 (Gr2) blunt only and Group 3 (Gr3) blast and blunt trauma.
Results:
Patients were categorized: 39 as Gr1, 18 as Gr2 and 33 as Gr3. The average age was 33.9, 38.4 and 35.1 years, respectively. Blurred vision (BV) was reported in (Gr1, Gr2, Gr3) 90%, 89% and 73%, photosensitivity (PT) in 85%, 73% and 79%, perception of field deficit (PVFD) in 23%, 44% and 27%. The average values for VA were: -0.063, -0.058 and -0.038 log MAR, for CS: 1.93, 1.75 and 1.69 log CS, for HVF mean deviation: -4.6, -4.4 and -4.0 dB, for total RNFL thickness: 99.7, 92.4 and 100.7 μm. There was no significant difference between the mean values of the three groups in any of the above measures. By quadrant analysis, mean temporal RNFL thickness was lower in all of the groups compared to a normal mean (p<0.0001), while Gr2 mean was lower compared to Gr1 (p<0.05).
Conclusions:
A large number of veterans with mild TBI reported subjective visual complaints such as BV and PT. Whether blunt, blast or both, the mechanism of injury did not affect the frequency of reported subjective symptoms. Similarly, VA, CS, HVF and RNFL thickness did not vary significantly between the trauma groups. However, measurements of temporal RNFL were lower than normal in all groups and significantly thinner in the blunt group. This leads us to believe that the mechanism of injury may determine damaging effects on already normally thin temporal RNFL. Chronology of multiple mechanism trauma may have an effect on RNFL damage as well.
Keywords: 742 trauma •
610 nerve fiber layer •
759 visual impairment: neuro-ophthalmological disease