Risk factors for the progression of treated primary open angle glaucoma: a multivariate life-table analysis

Background: Several factors have been reported as risk factors for the progression of primary open-angle glaucoma (POAG) but previous reports were not necessarily in agreement. We applied a multivariate life-table analysis to a large number of longitudinal data to deter mine the extent of the influence of various factors simultaneously. Methods: Two hundred fifteen eyes of 215 POAG patients were included. The follow-up period ranged from 24 to 134 months (average 82.7 months). The visual field stage was determined separately in upper and lower hemifields according to the classification of Aulhorn (modified by Greve). The progression was defined as an irreversible increase of the stage in at least one hemifield. The follow-up data were analyzed with the Cox proportional hazard model. Results: Mean intraocular pressure (IOP) in the follow-up period and the initial visual field stage significantly affected POAG progression (P < 0.05). The risk of POAG progression was calculated to double as the mean IOP increased by 4 mmHg. Eyes with the initial visual field of stage 0-1 and moderately advanced stages had a greater risk of progression than other stages. Conclusion: To prevent the progression of POAG, the IOP should be kept as low as possible, particularly at the early and moderately advanced stages.