Abnormal Peripapillary Nerve Fibre Layer Thickness Demonstrated by Optical Coherence Tomography in Cases of Optic Atrophy: Is There a Correlation With Aetiology?

Abstract

Optical coherence tomography of the peripapillary nerve fibre layer has been used in optic atrophy for identification of axonal loss and for differential diagnosis. In the present study, we aim to evaluate whether the pattern of peripapillary nerve fibre layer thinning, based on the optical coherence tomography normative database, correlates with aetiology in cases of optic atrophy. This retrospective study is approved by the Tan Tock Seng Hospital Ethics Review Board. Consecutive patients with optic atrophy seen in the Neuro-Ophthalmology Clinic between May 2005 and August 2006 were included. The normal eyes of the patients served as controls. All patients underwent imaging using Stratus optical coherence tomography of the peripapillary nerve fibre layer, optic disc photographs and Humphrey perimetry. The aetiology of each case of optic atrophy were made by means other than the optical coherence tomography. Significant nerve fibre layer thinning was defined as a reading in the red quadrant on the Stratus optical coherence tomography printout, which indicates the 1% percentile of the Stratus optical coherence tomography normative database. Twenty-nine patients (39 eyes) with optic atrophy were included in the study. The cases included non-arteritic anterior ischaemic optic neuropathy (14 eyes), compressive optic neuropathy (10 eyes), toxic optic neuropathy, traumatic optic neuropathy, previous optic neuritis, inflammatory optic neuropathy, and central retinal artery occlusion. Cases with isolated superior quadrant thinning were three times more likely to be non-arteritic anterior ischaemic optic neuropathy (odds ratio 4.07; 95% confidence interval: 0.8–20.75), although this was not statistically significant (p = 0.079). Patients with isolated superior peripapillary nerve fibre layer thinning on the Stratus optical coherence tomography are more likely to be non-arteritic anterior ischaemic optic neuropathy patients. The other aetiologies did not show any specific pattern of thinning.