Global and pointwise rates of decay in glaucoma eyes deteriorating according to pointwise event analysis.

PURPOSE

To estimate rates of change in glaucoma eyes deteriorating according to pointwise event analysis (Guided Progression Analysis, GPA).

METHODS

A total of 274 eyes with six or more reliable visual fields (vf) 5 years were enrolled (baseline mean deviation [MD]: -4.2 ± 4.5 dB). Pointwise and global rates of decay from linear regression analyses were estimated up to the time of VF deterioration according to GPA or until the last follow-up visit in stable eyes. Relationship of rates of decay with time to worsening and eccentricity and agreement of global and pointwise trend analyses with GPA were explored.

RESULTS

Seventy eyes (25.5%) worsened according to GPA. A statistically significant global rate of decay (P < 0.05) was observed in 54% (MD) and 62% (visual field index) of deteriorating eyes compared to 22% and 22% in stable eyes (κ = 0.32 vs. 0.37 for agreement with GPA). Rates of decay diminished with longer time to initial worsening and were faster in points within the central 10° of fixation compared to 20° and 30° regions (P = 0.025 and 0.279, respectively). Established criteria for pointwise linear regression (PLR) detected only 31% of locations deteriorating by GPA. Less stringent PLR criteria led to improved agreement with GPA at the expense of higher false detection rate.

CONCLUSIONS

Global and pointwise rates of decay decreased with longer time to VF deterioration. The agreement between pointwise event analysis and global trend analyses was fair. Less stringent criteria for PLR led to improved agreement with GPA at the expense of higher false detection rate.