Clinical accommodation testing.

Clinical accommodation tests can theoretically be categorized into five different types: 1) tests of accommodative amplitude, 2) tests of relative accommodation, 3) tests of accommodative facility, 4) tests measuring lag of accommodation, and 5) tests finding the dioptric accommodative stimulus at which dioptric stimulus and response levels are equal. Studies of the interrelation of accommodation tests indicate that a complete evaluation of accommodative disorders in nonpresbyopes should include at least one test from four of the five categories. Measurements of accommodative amplitude, lag, and facility, and relative accommodation should be included. Results from the fifth type of test listed above correlate well with lag of accommodation. Recent research is bringing greater acceptance and standardization to accommodative facility testing.