2014-07-04 at 11:30
A method for comparing psychophysical and multifocal electroretinographic increment thresholds
The multifocal electroretinogram (mfERG) has been commonly used as a method for obtaining objective visual fields. Although qualitative comparisons between the results from mfERG and the results from Humphrey Visual Field Analyzer (HVFA) have been good, quantitative comparisons have found variable degrees of agreement depending upon the mfERG response parameter examined and/or the disease studied. This lack of agreement may be due to differences in methodology, differences in the sites of response generation, and/or differences derived from comparing supra-threshold versus threshold responses. In addition, the two procedures are performed at different levels of adaptation. An approach to comparing mfERG and psychophysical thresholds based upon a two-site model of adaptation will be discussed. An application of this approach in individuals with retinal disease demonstrated that the relationship between the losses in the two measures can be used to predict the sites and mechanisms of disease.