Comparing a parallel PERG, automated perimetry, and frequency-doubling thresholds

PURPOSE. A pattern electroretinogram (PERG) simultaneously displaying the f requency-doubling (FD) illusion in nine parts of the visual field was compa red with two other methods for ability to detect glaucoma. This multiregion FD PERG (MFP) was compared with results from achromatic automated perimetr y and psychophysical tests using FD stimuli. METHODS. MFP data were compared with that from the Humphrey Field Analyser (HFA; Humphrey, San Leandro, CA) 24-2 program. Contrast thresholds were als o determined in different visual field locations for FD stimuli. Thin-plate spline methods were used to derive comparisons from the tests, each of whi ch sampled the visual field differently. RESULTS. Significant correlation with HFA could be obtained, providing seve n to nine (of nine) MFP amplitudes were themselves significant. Evidence sh owed that both the psychophysical tests using FD stimuli and the MFP detect glaucomatous damage not detected by the HFA. CONCLUSIONS. The comparisons between HFA perimetry, the MFP, and FD thresho lds indicate that both FD-based tests quantify a form of diffuse loss in ea rly glaucoma as well as the scotomas of later glaucoma.