Abstract
Purpose :
To measure the thickness and volume of individual retinal layers on optical coherence tomography (OCT) in people with prior traumatic brain injury (TBI).
Methods :
Adults ≥ 18 years old diagnosed with TBI or concussion were recruited from Duke neurology clinics. Individuals were assigned a TBI severity grade using the Veterans Affairs TBI criteria. Those with glaucoma, diabetes, optic neuropathy, retinal disease, and visual acuity worse than 20/40 were excluded. 512x128 macular cube volume scans were obtained using Zeiss Cirrus HD-5000 OCT. The previously validated Duke Reading Center Visualizer semi-automatically segmented (with manual correction) the ganglion cell and inner plexiform layer (GC+IPL), inner nuclear layer (INL), outer plexiform layer (OPL), outer nuclear layer (ONL), photoreceptor (PR) layer, and retinal pigment epithelium (RPE). Mean thickness and volume measurements were obtained within 3- and 6-mm ETDRS perifoveal rings, which were divided into superior, temporal, inferior, and nasal quadrants. Individuals were age- and sex-matched (±5 years) with controls.
Results :
59 eyes of 33 TBI subjects and 59 eyes of 33 controls were prospectively enrolled. Average age was 40±16 years, with 20 female subjects (61%) per cohort. Mean days from TBI to imaging was 1001 (range 264-2967 days). TBI severity was mild without loss of consciousness (LOC) in 21 eyes, mild with LOC in 33 eyes, and moderate in 5 eyes.
Mean thickness and volume of the 3-mm inferior ONL quadrant were increased (p<0.05) in TBI (thickness 69.5±10.2 μm, volume 0.11±0.02 mm3) vs. controls (65.4±10.8 μm, 0.10±0.02 mm3). In the 6-mm nasal RPE quadrant, thickness and volume were decreased (p<0.05) in TBI (thickness 19.1±2.20 μm, volume 0.10±0.01 mm3) vs. controls (20.1±2.72 μm, 0.11±0.01 mm3). There were trends for decreased thickness and volume of the 3-mm temporal GC-IPL quadrant (p=0.05) and increased thickness and volume of the 6-mm nasal INL quadrant (p=0.07) in TBI vs. controls. No significant differences were noted in thickness/volume of the neurosensory retina, OPL, or PR layers. 3-mm GC-IPL thickness and volume had negative correlations with days from TBI to imaging (r=-0.27 to -0.42, p<0.05).
Conclusions :
The thickness and volume of retinal layers may be impacted by TBI and the change may be progressive following TBI events. The diagnostic utility of individual retinal layer changes in TBI warrants further investigation.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.