Objective: We previously developed a method to measure visual function progression using "Progression sectors," which were derived from a clustering analysis of pointwise rates of glaucomatous visual field (VF) progression; however, only short series of VFs, where pointwise linear regression (PLR) is typically not reliable, were analyzed. The purpose of the current study is to further investigate the usefulness of a sector-wise approach in longer series of VFs where the accuracy of PLR is inherently greater.

Methods: We analyzed 16 VFs from each of 71 eyes in 45 patients. Sectorial averages of total deviation (TD) values were calculated at each "Progression sector," consisting of 23 sectors as well as at "Nouri-Mahdavi" (NM) sectors, consisting of 10 sectors. Linear regression then was applied to predict sectorial averages in the 11th to 16th VFs and absolute prediction errors were compared to PLR.

Results: Absolute prediction errors associated with linear regression of the "Progression sectors" were significantly smaller than those from PLR (P < 0.05) when predicting values in the 14th to 16th VFs. Conversely, prediction errors with NM sectors were significantly larger than those from PLR and "Progression sectors" (P < 0.01) when predicting values in the 11th to 16th VFs.

Conclusions: It is useful to use "Progression sectors" to predict future VF progression in short (1-10 VFs) and long (>10 VFs) VF series, compared to PLR and NM sectors.