Total variance of serial Octopus visual fields in glaucomatous eyes

Abstract

Using Octopus program 32, we studied ten eyes of five patients with well controlled primary open angle glaucoma and known visual field disturbances attributed to this disease. A series of eight static threshold fields were performed on each eye over a one month period. For each series, two-way analysis of variance (ANOVA) employing a random-effects model was applied [8,10]. The components of variance were estimated from the ten duplicate thresholds provided routinely on normal bracketing programs. Estimated values for the components of variance attributed to test location, short-term fluctuation (SF), and homogenous long-term fluctuations [HO (LF)] were equivalent to published values using program JO [2, 6]. Heterogeneous long-term fluctuation [HE (LF)] for this group were larger than previously reported [1, 6] and accounted for a significant proportion of total variance (V_T). This study demonstrates that useful information concerning long-term fluctuation is available free of additional perimetric time penalty using standard programs. The recognition of progressive trends in serial fields would be enhanced if the components which determine fluctuations were profiled individually.