Validity of a new disk grading scale for estimating glaucomatous damage: correlation with visual field damage.

Purpose: To determine the correlation of a new disk grading system, the disk damage likelihood scale (DDLS), with the visual field damage in patients with glaucoma.

Design: Observational case series.

Methods: Charts of 75 patients (150 eyes) with primary open-angle glaucoma (POAG), 41 patients (82 eyes) with low-tension glaucoma (LTG), and 25 patients (50 eyes) with pseudoexfoliative glaucoma (PXFG) were reviewed retrospectively. DDLS stages and vertical disk sizes were recorded. A masked observer staged the Humphrey field analyzer (program 24-2) visual fields using the Hodapp-Parrish-Anderson (HPA) visual field staging system. Mean deviation (MD) and pattern standard deviation (PSD) values were obtained. The correlation of DDLS with the visual field parameters and HPA staging system were evaluated. Findings were assessed by the Pearson and Spearman correlation coefficients.

Results: In the 282 eyes studied, the DDLS was strongly correlated with both MD (Pearson r = - 0.695, P <.001) and PSD (Pearson r =.703, P <.001). The HPA visual field staging system was also strongly correlated with the DDLS (Spearman r =.711, P <.001). These relationships continued to be significant when the three diagnostic groups (POAG, LTG, PXFG) were evaluated separately (P <.001) and also for small (< 1.5 mm) and average size (1.5-2.0 mm) disks. Large disks (> 2.0 mm) were not evaluated, because there was an insufficient number of cases.

Conclusion: DDLS, a new system for estimating glaucomatous disk damage, strongly correlates with the degree of glaucomatous visual field damage.