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Abstract #60302 Published in IGR 16-4
Evaluation of a Method for Estimating Retinal Ganglion Cell Counts Using Visual Fields and Optical Coherence Tomography
Raza AS; Hood DCInvestigative Ophthalmology and Visual Science 2015; 56: 2254-2268
PURPOSE: To evaluate the accuracy and generalizability of a published model that derives estimates of retinal ganglion cell (RGC) counts and relates structural and functional changes due to glaucoma. METHODS: Both the Harwerth et al. non-linear model (H-NLM) and the Hood and Kardon linear model (HK-LM) were applied to an independent dataset of frequency-domain optical coherence tomography and visual fields, consisting of 48 eyes of 48 healthy controls, 100 eyes of 77 glaucoma patients and suspects, and 18 eyes of 14 non-arteritic anterior ischemic optic neuropathy (ION) patients with severe vision loss. Using the coefficient of determination R(2), the models were compared while keeping constant the topographic maps, specifically a map by Garway-Heath et al. and a separate map by Harwerth et al., which relate sensitivity test stimuli locations to corresponding regions around the optic disc. Additionally, simulations were used to evaluate the assumptions of the H-NLM. RESULTS: Although the predictions of the HK-LM with the anatomically-derived Garway Heath et al. map were reasonably good (R(2) = 0.31 to 0.64), the predictions of the H-NLM were poor (R(2) < 0) regardless of the map used. Furthermore, simulations of the H-NLM yielded results that differed substantially from RGC estimates based on histology from human subjects. Finally, the value-added of factors increasing the relative complexity of the H-NLM, such as assumptions regarding age- and stage-based corrections to structural measures, was unclear. CONCLUSIONS: Several of the assumptions underlying the H-NLM should be revisited. Studies and models relying on the RGC estimates of the H-NLM should be interpreted with caution.
Department of Psychology, Columbia University, 1190 Amsterdam Ave, MC 5501, 301 Schermerhorn Hall, New York, NY, 10027, United States.
Full articleClassification:
2.13 Retina and retinal nerve fibre layer (Part of: 2 Anatomical structures in glaucoma)
6.6.2 Automated (Part of: 6 Clinical examination methods > 6.6 Visual field examination and other visual function tests)
6.9.2.2 Posterior (Part of: 6 Clinical examination methods > 6.9 Computerized image analysis > 6.9.2 Optical coherence tomography)
