Learning Effect and Test-Retest Variability in Healthy Subjects and Patients with Primary Open Angle Glaucoma Using Rarebit Perimetry

Aim: To study learning effect (LE) and test retest variability (TRV) in healthy subjects and patients with primary open angle glaucoma (POAG) using Rarebit perimetry (RBP). To determine normative ranges of RBP. Methods: 61 eyes of 35 subjects underwent visual field testing with standard automated perimetry (SAP) and RBP. TRV and LE were assessed in repeated examinations conducted in 3 different days. First two examinations were conducted within 3 days and the last one within one month. LE was assessed by comparing results from the three sessions. TRV was evaluated by calculating differences between retest for each combination of single tests. To determine normative ranges of RBP were included 34 eyes of 21 healthy subjects and 62 eyes of 47 subjects with preperimetric and early POAG. Cut off value was determined between the two groups using ROC analysis. Results: No significant LE was observed in POAG group. There was a significant LE in the control group but only in the visual field zones with eccentric location. TRV was higher in POAG group and in central visual field zone. The mean MHR in control group was 94.88 (SD 2.21) and 83.56 (SD 6.95) in POAG group. Cut off value for discriminating between healthy subjects and patient with POAG was 91.50% with AUROC 0.985 (p<0.001, ROC analysis). Conclusion: RBP is fast and easy to perform test. RBP testing did not show a significant LE in glaucoma group, however, TRV was consistent. MHR can be successfully used for differentiation of healthy eye from those with early glaucoma changes.