Assessment of current visual psycho-physical testing methods with special reference to primary open angle glaucomatous disease (POAGD)

Abstract

Early diagnosis of glaucoma with standard perimetric technique remains unsatisfactory as the appearance of discernible visual field defects indicates already extensive optic nerve fiber loss. Experimental evidence, reviewed here in detail, indicates that retinal neurons selective for coarse, temporally modulated patterns are most vulnerable in early glaucoma. Applying this data to perimetric techniques the authors have designed a new test measuring paracentral contrast sensitivity. By presenting sinusoidal gratings of 1 cpd four degrees from fixation, contrast sensitivity was determined as a function of stimulus size. They obtained abnormal contrast sensitivity functions in glaucoma suspects with apparently intact visual fields indicating the potential for better detection of hidden glaucomatous nerve damage.