Purpose:
Optic Nerve swelling is difficult to quantify clinically and may not correlate with visual field loss. We examine retinal nerve fiber layer rNFL) thickness characteristics as measured by Stratus Optical Coherence Tomography (OCT) in patients with optic nerve swelling from raised intracranial pressure at the time of presentation. We further attempt to show if a relationship exists between severity of Mean Deviation (MD) loss and rNFL thickness.
Methods:
Retrospective chart review. Subjects were included if reliable 24–2 Humphrey visual field (HVF) testing and OCT of the peripapillary rNFL were performed within 8 days of each other at the time of presentation. Eyes were divided based on the amount of MD depression from 0 to –10dB (mild loss), –10dB to –20dB (moderate loss) and greater than –20 dB (severe loss). The severe group was further divided into those with and without optic atrophy. OCT readings were taken for the averages of the superior, inferior, temporal and nasal quadrants. Both absolute measurements as well as percent change from a normative database were calculated.
Results:
14 patients had pseudotumor cerebri, two dural sinus thrombosis and one cerebral vasculitis. Comparison of rNFL change (thickness and percent change) of four quadrants and severity of MD depression
Conclusions:
The superior quadrant of the optic nerve showed the highest elevation of any quadrant across all severities of MD depression. The nasal quadrant showed the greatest change in percentage across all severities. OCT detected loss of rNFL in patients with optic atrophy. The consistent increase in rNFL thickness as MD worsened suggests a relationship exists between the two. Measuring rNFL thickness in patients with disc swelling at time of presentation may be helpful in gauging the severity of visual field loss. OCT may also be helpful for the confirmation of the clinical presence of optic atrophy.
Keywords: imaging/image analysis: clinical • neuro-ophthalmology: optic nerve • visual fields