Combined OCT retinal nerve fibre layer analysis and VEP in neuro‐ophthalmic disease

Abstract

Abstract Purpose Ocular Coherence Tomography (OCT) has become a valuable tool in assessing retinal nerve fibre layer thickness (RNFL) in Patients with optic nerve disease. This study is designed to compare RNFL thickness n with Visual Evoked Cortical Potentials (VECP)in patients with known optic nerve disease and comparing these to a group of patients with primary open angle glaucoma (POAG). Methods Twenty Patients (37 eyes) with clinically determined optic nerve disease underwent pattern reversal VECP and also OCT using a Spectralis OCT system. Assessment of global and segmental RNFL was made. Six Patients were diagnosed as Dominant Optic atrophy, 3 with Lebers Optic Neuropathy (LHON), 6 with Nutritional amblyopia, 3 with Anterior Ischaemic Optic Neuropathy (AION), and 2 with Demyelinating disease. These Patients were also compared to a group of 10 patients (20 eyes) with Primary Open Angle Glaucoma POAG. Results Pattern reversal VECP were abnormal in 32/37 eyes (86%): 26/32 (81%) of these being of reduced amplitude, and 20/32 (62%) being delayed. Amongst the patients with POAG only 4/20 eyes (20%) had abnormal VECP, and none were delayed. Thinning of the RNFL occurred in 36/37 eyes (97%) with optic nerve disease; 24 (65%) had global thinning, and the remainder segmental thinning only. All of the eyes with POAG had RNFL thinning but only 6/20 eyes (30%) had global thinning. Bipolar cell thinning of the central retina was noted in 6 eyes with optic nerve disease. Conclusion OCT is a valuable tool in the assessment of patients with optic nerve disease. Thinning of the RNFL was a more consistent finding than delay of the VECP in optic nerve disease, and a combination of VECP and OCT is helpful in the differential diagnosis of low tension glaucoma and optic nerve disease.