The use of different-sized stimuli in automated perimetry

Eighteen patients with glaucoma who failed to respond (0 dB) to maximum intensity (1,000 apostilbs) No. 3 (4 mm2) stimuli during threshold static perimetry performed with an Octopus automated perimeter were retested using the same test program with No. 5 (64 mm2) stimuli. All responded to the larger stimulus at the 5-dB (315 apostilbs) level or higher in at least three previously undetected locations. Ten of the 18 patients responded in at least 80% of the locations they were unable to detect with smaller stimulus. After four patients were tested twice with the No. 5 stimulus the improvement in response was confirmed. The use of the larger-sized stimulus permitted us to measure visual function in areas that had been considered absolute scotomas with the standard-sized stimulus. In this way, we can monitor changes that may occur in these areas in the future.