Effect of eye testing order on automated perimetry results using the Swedish Interactive Threshold Algorithm standard 24-2.

OBJECTIVE To evaluate whether the order of eye testing affects the mean deviation (MD) or the test reliability of visual field testing using the Swedish Interactive Threshold Algorithm (SITA) standard 24-2. METHODS Consecutive patients with manifest or suspect glaucoma with 2 prior sets of SITA standard 24-2 test results performed on the right eye first were enrolled. A subsequent test was performed on the left eye first. For each eye, the MD and the test reliability indexes (> or = 20%) were compared among the 3 successive examinations. RESULTS Forty-seven patients (29 women and 18 men; mean +/- SD age, 70.6 +/- 11.9 years) were enrolled. The MD +/- SD was -5.83 +/- 5.43 dB OD and -5.46 +/- 4.86 dB OS. There was no statistically significant difference in the MD or the test reliability among the 3 test results for either eye. Fixation loss was responsible for the unreliable fields in almost all cases. CONCLUSIONS Among this cohort of patients experienced with automated perimetry in a glaucoma subspecialty practice, changing the order of eye testing using the SITA standard 24-2 did not have a significant effect on the MD or the test reliability. Intereye fatigue may not be clinically significant with this algorithm. Fixation loss remains a problem with the use of this algorithm.