Correlation of Retinal Nerve Fibre Layer Thickness in Optical Coherence Tomography with Visual Outcome in Optic Neuritis

Abstract

Abstract Purpose: In this study, the changes in optical coherence tomography (OCT) were correlated with the post-treatment visual outcome of optic neuritis, thereby determining the patients who are at risk of optic atrophy. Design: Prospective observational study. Methodology: All patients presenting to the outpatient department (OPD) with acute visual loss, pain on ocular movements and colour desaturation were subjected to comprehensive ophthalmic examination and OCT retinal nerve fibre layer (RNFL) analysis. All patients were treated with an Optic Neuritis Treatment Trial (ONTT) regimen and followed for one year. Results: Of 25 patients, 40% were 20 to 40 years of age, and females outnumbered males by 28%. The right eye had 48% unilateral affection and 12% bilateral affection; 56% had a central scotoma, and 24% had a centrocaecal scotoma. The most common aetiologies are as follows: idiopathic (84%), multiple sclerosis (MS) (12%) and Devic’s disease (4%). 60% presented with a visual acuity of 6/60–1/60 and 32% with a visual acuity of 6/18–6/36. Patients whose RNFL thickness was below 90 microns post-treatment had poorer visual outcome. Conclusion: In this study, optic neuritis was more common in females of 20 to 45 years with unilateral affection in the right eye. The most common field defect was central scotoma, and the most common cause of optic neuritis was idiopathic. It was also found that the visual acuity in optic neuritis can range from 6/18 to no PL. Of the 25 patients in the study, three patients had retrobulbar neuritis and six patients developed disc pallor during recovery after treatment.