Progression to blindness in 20 years among patients with glaucomatous visual field loss in a tertiary hospital in the Philippines

Objective To determine visual field (VF) rates of change among patients with glaucomatous VF loss and proportion of those becoming blind based on residual life expectancy and factors associated with fast progression. Methods and analysis This was a retrospective study of the VFs of patients with glaucomatous VF defects in at least one eye. Baseline and final VFs were reviewed. Rates of VF change (decibels (dB)/year) for each eye, together with the residual life expectancy based on age and sex, were used to predict mean deviation/defect (MD) at the end of expected lifetime. Blindness was defined if computed MD was 22 dB (Octopus) or -22 dB (Humphrey) or worse in the better eye. Factors associated with fast progression (>1 dB/year for Octopus or <-1 dB/year for Humphrey) and blindness were determined. Results There were 1016 eyes of 583 patients eligible. There was decline in VF MD/year in 613/1016 (60.3%), 95% CI (57.3% to 63.3%) of eyes; however, only 98/1016 (9.7%), 95% CI (7.9% to 11.5%) of eyes showed fast progression. Among patients with bilateral VFs, 43/433 (9.9%), 95% CI (7.1 to 12.8) of eyes were predicted to progress to blindness. In multivariate analysis, factors associated with fast progression were baseline MD (p<0.001) and male sex (p=0.041). Factors associated with blindness were age <60 years (p=0.003), baseline MD (p=0.022), bilateral glaucomatous VF defects (p=<0.001) and fast progression (p<0.001). Conclusion Patients reaching blindness in a routine clinical setting was 10%. Because of association of age and baseline MD on blindness, early disease detection is important. VF progression rates and residual life expectancy must be incorporated in glaucoma care.