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 ( >= 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.