title: Optic Disc and Macular Imaging in Blind Eyes from Non-glaucomatous Optic Neuropathy: A Study with Spectral-domain Optical Coherence Tomography.
abstract: The purpose of this study was to determine and compare the optic disc and macular thickness measurements using two spectral-domain optical coherence tomography (SD-OCT) instruments in long-standing blind eyes diagnosed with non-glaucomatous optic neuropathies (NGON). A prospective observational case-series design was used. Twelve eyes from 12 NGON patients with no light perception for at least 6 months underwent optic disc and macular imaging with Cirrus HD-OCT and Spectralis OCT. The correlation between the peripapillary retinal nerve fibre layer (PRNFL) and macular ganglion cell layer and inner plexiform layer (GCL+IPL) thicknesses, and between the duration of no light perception (NLP) and PRNFL/GCL+IPL thicknesses were determined using Spearman's correlation analysis. The mean average PRNFL thickness was 55.9 ± 4.8 µm for Cirrus HD-OCT, which was significantly thicker than that measured by Spectralis OCT (31.9 ± 7.4 µm;p< 0.001). The mean central macular thickness on Cirrus HD-OCT was normal, but there was global thinning at the other macular areas. The mean average GCL+IPL thickness on Cirrus HD-OCT was 51.8 ± 5.8 µm. There was a good correlation between average PRNFL thickness and GCL+IPL thickness (r= 0.830,p= 0.002); however, there was no significant correlation between the duration of NLP to the average PRNFL thickness (on either instruments) or GCL+IPL thickness on Cirrus HD-OCT (p> 0.7). These results show that there was residual PRNFL thickness in NGON eyes with NLP, which varied significantly between SD-OCT instruments. The values of the residual PRNFL and GCL+IPL thicknesses in blind eyes (the "floor" effect) may be useful for prognostic purposes for patients with partial optic atrophy.
authors.affiliation: Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong; Hong Kong Eye Hospital, Kowloon, Hong Kong; Department of Ophthalmology, Faculty of Medicine, Chiang Mai University, Chiang Mai, Thailand.
authors.forename: Linda
authors.initials: L
authors.lastname: Hansapinyo
authors.affiliation: Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong; Hong Kong Eye Hospital, Kowloon, Hong Kong; Department of Ophthalmology, Hong Kong Sanatorium & Hospital, Hong Kong.
authors.forename: Andy C O
authors.initials: AC
authors.lastname: Cheng
authors.affiliation: Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong; Hong Kong Eye Hospital, Kowloon, Hong Kong.
authors.forename: Noel C Y
authors.initials: NC
authors.lastname: Chan
authors.affiliation: Department of Ophthalmology and Visual Sciences, The Chinese University of Hong Kong, Hong Kong; Hong Kong Eye Hospital, Kowloon, Hong Kong.
authors.forename: Carmen K M
authors.initials: CK
authors.lastname: Chan
keywords: Blind eye; macular thickness; non-glaucomatous optic neuropathy; peripapillary retinal nerve fibre; spectral-domain optical coherence tomography