THE INFLUENCE OF STIMULUS PARAMETERS ON THE VISUAL-FIELD INDEXES BY AUTOMATED PROJECTION PERIMETRY

The various stimulus parameters offered by two standard automated proj ection perimeters [Humphrey Field Analyser 630 (HFA) and Octopus 201], namely, stimulus size and location and the interaction of adaptation level and stimulus duration, were compared in a sample of 20 patients attending a glaucoma clinic using the visual field indices mean defect (MD), loss variance (LV), short-term fluctuation (SF) and corrected l oss variance (CLV). LV and SF were greater with Octopus program 32 com pared with Octopus program G1 (P < 0.02). No difference in the indices was found between stimulus sizes I and III for HFA program 30-2. MD w as greater for program 30-2 compared with program 32 (P < 0.002) when expressed in terms of log (L/DELTAL) whereas LV (P < 0.02) and SF (P < 0.02) were greater for program 32. All differences were considered to be negligible in the clinical sense.