Through a series of research and design studies, the Principal Investigator has arrived at a technique and apparatus concept for a diagnostic test for glaucoma which promises to confirm functional loss at a stage of the disease before there are reliable signs of visual field loss, a high priority aim of research in the glaucoma area. Preliminary data on populations of normal subjects, glaucoma suspects and confirmed glaucoma patients show no overlap in test scores between the normal subjects and the confirmed glaucoma patients. Statistically significant differences were also found between the mean scores of normal and of suspects. and between mean scores of suspects and of confirmed cases. It is proposed here to do an enlarged and improved study, which will meet more exacting criteria by having the selection and documentation of subjects performed by a glaucoma specialist, unavailable in the preliminary studies, and by keeping the testing personnel masked from the diagnosis. The diagnostic technique utilizes a new approach that involves opposing achromatic and chromatic stimulation in the pattern ERG, which provides a null point measurement which is less variable than the usual measurement. The preliminary data show very clearly that the null point shifts significantly in glaucoma. It shifts in a way which provides evidence that luminance ganglion cells are lost before color-opponent ganglion cells in glaucoma, which meshes with anatomical evidence. The proposed approach also has the advantage of fully automatic testing with the patient required only to maintain fixation, obviating the need for the patient to make frequently difficult subjective judgments. It also shows promise, which will be studied, of very rapid assessment of visual field loss and of treatment effectiveness, utilizing new signal processing procedures.
