T Maddess1, A C James, I Goldberg, S Wine, J Dobinson. 1. Centre for Visual Sciences, Research School of Biological Sciences, Australian National University, Canberra. Prince of Wales Hospital, Sydney, Australia. ted.maddess@anu.edu.au
Abstract
PURPOSE: A pattern electroretinogram (PERG) in which stimuli displaying the frequency-doubling (FD) illusion are presented simultaneously to multiple parts of the visual field was evaluated for its ability to diagnose glaucoma. This multiregion FD PERG is referred to in the current study as the MFP. METHODS: The nine stimulus regions were temporally modulated at incommensurate frequencies typically producing an FD percept. Two other spatial scales of the stimuli were also investigated. The sensitivity and specificity of MFP were examined using linear and quadratic discriminant methods. RESULTS: Even with the simpler linear discriminant classification, sensitivities and specificities of 100% were obtained in eyes with moderate to severe glaucoma. Of eyes with glaucoma strongly suspected, 67% were classified as being glaucomatous. Stimulus patterns having differing spatial scales produced different PERG visual field dependencies. CONCLUSIONS: The differing results for the 16-fold change in spatial scale may reflect the accessing of different mechanisms. The MFP method appears to have significant value for the diagnosis of glaucoma.
PURPOSE: A pattern electroretinogram (PERG) in which stimuli displaying the frequency-doubling (FD) illusion are presented simultaneously to multiple parts of the visual field was evaluated for its ability to diagnose glaucoma. This multiregion FD PERG is referred to in the current study as the MFP. METHODS: The nine stimulus regions were temporally modulated at incommensurate frequencies typically producing an FD percept. Two other spatial scales of the stimuli were also investigated. The sensitivity and specificity of MFP were examined using linear and quadratic discriminant methods. RESULTS: Even with the simpler linear discriminant classification, sensitivities and specificities of 100% were obtained in eyes with moderate to severe glaucoma. Of eyes with glaucoma strongly suspected, 67% were classified as being glaucomatous. Stimulus patterns having differing spatial scales produced different PERG visual field dependencies. CONCLUSIONS: The differing results for the 16-fold change in spatial scale may reflect the accessing of different mechanisms. The MFP method appears to have significant value for the diagnosis of glaucoma.