Binocular accommodative facility testing reliability.
This study evaluated the reliability of the 1-min binocular accommodative facility test by extending the testing period for 2 additional minutes. Subjects, ages 8 to 12 years, were tested for an initial 1-min period, to identify 2 groups, high fail (greater than 3, but less than 8 cpm, N = 30) and low fail (less than 3 cpm, N = 30), and then tested for an additional 2 min. The low fail group had greater test-retest reliability in both minutes 2 and 3. Both groups improved (high fails mean = 0.93 cpm, low fails mean = 0.37 cpm), but no clear statistical difference was found between groups. When diagnostic classification was monitored over the 3 min, 40% of high fails passed, whereas no low fails passed. The 1-min testing method appears reliable if the initial rate is less than 3 cpm. For patients whose initial rate is between 3 and 8 cpm, extended testing (1 to 2 additional minutes) may be needed to arrive at an accurate diagnosis, especially if presenting symptoms are absent.