Clinical alternative for reducing the time needed to perform automated threshold perimetry

Automated threshold perimetry is an important test used to diagnose and monitor open angle glaucoma. Unfortunately, the test can be tedious and demands that a patient concentrate for up to fifteen minutes or more per eye to achieve useful results. Many individuals are not capable of fixating for extended periods, and the reliability of the automated threshold test consequently suffers. This paper explores alternative methods to perform automated threshold perimetry so that the time required for testing is reduced while the clinical impact of performing abbreviated tests is minimized.

Several different versions of a central automated threshold perimetry test were run on a cooperative, normal individual utilizing a Humphrey Field Analyzer. One field was run on consecutive days in one eye only. The 24-2 and 30-2 test patterns were performed using the standard threshold format, FastPac, and certain modifications (involving the short-term fluctuation monitor and the fixation monitor) to measure the time required for the test to be performed and monitor any changes in the global indices as measured by the tests.

The 30-2 automated threshold test requires about 13 minutes to perform while a similar central threshold test, the 24-2 test, run in a modified format (without the short-term fluctuation monitor and/or the fixation monitor) was performed in about five minutes.

There are several methods that may be used to reduce perimetric testing time without compromising significantly the reliability of the diagnostic information. Reduced testing time may enable the clinician to obtain reliable fields in certain patients whose data are deemed unreliable when performing lengthier tests. The clinician must decide which data may be lost when testing time is reduced since clinical decision-making is inevitably affected whenever clinical data is not gathered.