Does Changing Eye Test Order With 24–2 SITA Standard Result in a Meaningful Change in Test Results?

Abstract

Abstract: : Purpose: The 24–2 SITA standard (SS) algorithm is potentially less affected by patient fatigue due to reduced test duration. We evaluated whether the order of the eyes tested with 24–2 SS affects field sensitivity or reliability in routine clinical practice. Methods: Consecutive glaucoma patients or suspects with 2 prior sets of 24–2 SS VFs taken OD first ("test 1" and "test 2") were enrolled. The next VF test was performed OS first ("test 3"). All patients were experienced with automated perimetry and had visual acuity > 20/60. Duration between exams was less than 20 months. For each eye, MD was compared among the 3 successive exams using Repeated Measures ANOVA. A field was considered reliable if all indices were less than 20%. Results: 49 persons (30 F, 19 M) were enrolled (mean age 70.4±11.8 years). Mean MD was OD: –5.98±5.30 dB and OS: –5.64±4.71 dB. There was no statistically significant change in MD between the 3 field tests of each eye. Testing the left eye first had no effect on exam reliability. Overall, unreliable fields were obtained in 30.6% of right eyes and 33.3% of left eyes. Fixation loss was responsible for unreliability in almost all cases (87.0% of right eyes and 95.9% of left eyes). Conclusions: In this cohort of experienced visual field takers, changing the order of eyes tested with the SS 24–2 algorithm did not have a significant effect on mean deviation or test reliability. Inter–eye fatigue may not be clinically significant with this algorithm. Fixation loss remains a problem even with the short 24–2 SS algorithm and was not affected by eye order in this study.

Keywords: visual fields • perimetry