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Relationship between psychophysical measures of retinal ganglion cell density and in vivo measures of cone density in glaucoma

Matlach, Julie, Mulholland, Padraig, Cilkova, Marketa, Chopra, Reena, Shah, Nilpa, Redmond, Tony, Dakin, Steven, Garway-Heath, David and Anderson, Roger (2016) Relationship between psychophysical measures of retinal ganglion cell density and in vivo measures of cone density in glaucoma. Ophthalmology, 124 . pp. 1-30. [Journal article]

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URL: http://www.sciencedirect.com/science/article/pii/S0161642016318097

DOI: 10.1016/j.ophtha.2016.10.029

Abstract

Purpose: There is considerable between subject variation in retinal ganglion cell (GC) density in healthy individuals, making identification of change from normal to glaucoma difficult. Ascertaining local cone:GC density ratios in healthy individuals, we wished to investigate the utility of objective cone density estimates as a surrogate of baseline GC density in glaucoma patients, and thus a more efficient way of identifying early changes.Design: Exploratory cohort study.Participants: Twenty glaucoma patients (60% female) with a median age of 54 years and mean deviation (MD) in the visual field (VF) of -5 dB and 20 healthy controls (70% female) with a median age of 57 years and MD of 0 dB were included.Methods: Glaucoma patients and healthy subjects underwent in vivo cone imaging at 4 locations of 8.8° eccentricity with a modified Heidelberg Retina Angiograph HRA2 (scan angle of 3°). Cones were counted using an automated programme. GC density was estimated at the same test locations from peripheral grating resolution acuity (PGRA) thresholds.Main Outcome Measures: Retinal cone density, estimated GC density and cone:GC ratios in glaucoma patients and healthy controls.Results: Median [interquartile range, IQR] cone:GC density was 3.51:1 [2.59:1, 6.81:1] in glaucoma patients compared to 2.35:1 [1.83:1, 2.82:1] in healthy subjects . GC density was 33% lower in glaucoma patients than in healthy subjects, however cone density was very similar in glaucoma patients (7,248 cells/mm2) and healthy controls (7,242 cells/mm2).The area under the receiver operator characteristic curve was 0.79 (95% confidence interval [CI] 0.71-0.86, P<0.001) for both GC density and cone:GC ratio, and 0.49 (95% CI 0.39-0.58, P=0.79) for cone density.Conclusions: Local measurements of cone density do not differ significantly from normal in glaucoma patients despite large differences in GC density. There was no statistically significant association between GC density and cone density in the normal participants, and the range of cone:GC density ratios was relatively large in healthy controls. These findings suggest that estimates of baseline GC density from cone density are unlikely to be precise, and offer little advantage over determination of GC alone in the identification of early glaucomatous change.

Item Type:Journal article
Keywords:Retinal cone mosaic, glaucoma, ganglion cell density, psychophysics, cone imaging, Heidelberg Retina Angiograph
Faculties and Schools:Faculty of Life and Health Sciences > School of Biomedical Sciences
Faculty of Life and Health Sciences
Research Institutes and Groups:Biomedical Sciences Research Institute
Biomedical Sciences Research Institute > Optometry and Vision Science
ID Code:36231
Deposited By: Dr Padraig Mulholland
Deposited On:18 Nov 2016 10:17
Last Modified:09 Dec 2017 18:57

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