Automated Perimetry Under the Microscope: A Re-Examination of Fundamental Assumptions.

Automated perimetry, a vision test that is likely performed thousands of times a day within the Unites States alone, has been conducted largely unchanged for several decades. It is also true that many of the fundamental parameters of this form of testing were adopted wholesale from manual kinetic perimetry. Research is now emerging, which suggests that many aspects of automated perimetry, from the range of stimulus intensities used and the arrangement of these stimuli into a test pattern, to the stimulus size and duration used, may not be optimal. Mulholland and colleagues provide evidence that the stimulus duration most commonly used in automated perimetry, 200 ms, is substantially longer than the critical duration of complete temporal summation for this type of stimulus. In addition, the critical duration of complete temporal summation appears to increase in eyes with glaucoma. The authors of this work conclude that the stimulus duration and stimulus area used in ‘conventional Standard Automated Perimetry (SAP) may be suboptimal for identifying early functional damage.’ In the future, automated perimetry may be afforded improved sensitivity for early functional damage through the development of testing algorithms that may modulate stimulus duration, area, or luminance. A careful reevaluation of the basic assumptions of one of the most commonly performed clinical vision tests stands to positively impact hundreds of thousands of patients each year.