Natural History of Open-Angle Glaucoma

The median and interquartile rates of visual function loss were −0.40 (1.05) dB/year overall and −0.46 (1.61) in HTG, −0.22 (0.65) in NTG, and −1.13 (6.13) in PEXG. Thus, interpatient variability was large. Mean rates were considerably higher than medians: −1.08 dB/year overall, −1.31 in HTG, −0.36 in NTG, and −3.13 in PEXG. Differences in median visual function progression rates among groups were statistically significant (NTG vs. HTG, P = 0.003; PEXG vs. non-PEXG, P<0.001). Progression was considerably and significantly faster in older than in younger patients (P = 0.002). By 6 years, 68% of patients had progressed overall, 74% of those with HTG, 56% of those with NTG, and 93% of those with PEXG (P = 0.012). Median time to progression also differed considerably among groups: 19.5 months in PEXG, 44.8 months in HTG, and particularly 61.1 months in NTG (P<0.0001).
ConclusionsIn this 6-year follow-up study, the median untreated rate of progression corresponded to advancing from normal visual function to blindness in approximately 70 years, whereas on the basis of the mean rate, visual function would show the same deterioration in approximately 25 years. Large differences existed among patients and different glaucoma types, with PEXG progressing considerably faster than HTG, and NTG progressing at the lowest rate.