Evaluation of Octopus Polar Trend Analysis for Detection of Glaucomatous Progression

Abstract

To investigate the clinical usefulness of Polar Trend Analysis (PTA) of the Octopus Field Analysis software for detection of glaucoma progression in medically treated glaucoma. One eye each of 52 participants underwent Octopus Normal G2 perimetry and imaging with the RTVue-100 optical coherence tomograph at 6-month intervals (median follow-up 5 years). The eyes were classified as progressors or nonprogressors with PTA, which graphically presents pointwise linear regression analysis of focal defect at the corresponding nerve fiber angle at the disc margin. Polar Trend Analysis progression was defined as more than 1 significantly progressing test point location per sector. Progression of the retinal nerve fiber layer thickness (RNFLT) and ganglion cell complex (GCC) thickness parameters were evaluated with linear regression analysis. Seventeen eyes were classified as PTA progressors (all in the inferotemporal or superotemporal areas or in both), and 35 eyes as nonprogressors. Frequencies of statistically significant RNFLT and GCC progressions did not differ significantly between the groups for any peripapillary area (p>0.05 for all comparisons). Significant inferior average RNFLT progression occurred in 50% of the PTA progressor eyes. Long-term measurement variability during the follow-up period was significantly higher in the PTA progressor group for inferior and superior GCC thickness and inferior average RNFLT (p<0.001 for all comparisons). In glaucoma, PTA may indicate glaucomatous progression earlier than linear regression analysis of the RNFLT and GCC parameters. It may already draw attention to glaucomatous progression when the alteration of the corresponding structural parameters is represented only by increased long-term variability.