Abstract :
PURPOE: In a companion paper, we determined that intraocular preure i part of the pathogenei of normal-tenion glaucoma by analyzing the effect of a 30% intraocular preure reduction on the ubequent coure of the dieae. We report an intent-to-treat analyi of the tudy data to determine the effectivene of preure reduction.
METHOD: One eligible eye of 145 ubject with normal-tenion glaucoma wa randomized either to no treatment (control) or to a 30% intraocular preure reduction from baeline. To be eligible for randomization, the normal-tenion glaucoma eye had to how documented progreion of field defect or a new dik hemorrhage or had to have field defect that threatened fixation when firt preented for the tudy. urvival analyi compared time to progreion of all randomly aigned patient during the coure of follow-up from the initial baeline at randomization. In a eparate analyi, data of patient developing cataract were cenored at the time that cataract produced 2 line of nellen viual acuity lo.
REULT: Viual field progreion occurred at inditinguihable rate in the preure-lowered (22/66) and the untreated control (31/79) arm of the tudy (P = .21). In an analyi with data cenored when cataract affected viual acuity, viual field progreion wa ignificantly more common in the untreated group (21/79) compared with the treated group (8/66). An overall urvival analyi howed a urvival of 80% in the treated arm and of 60% in the control arm at 3 year, and 80% in the treated arm and 40% in the control at 5 year. The Kaplan-Meier curve were ignificantly different (P = .0018). The analye gave different reult becaue of a higher incidence of cataract in the group that underwent filtration urgery.
CONCLUION: The favorable effect of intraocular preure reduction on progreion of viual change in normal-tenion glaucoma wa only found when the impact of cataract on viual field progreion, produced largely by urgery, wa removed. Lowering intraocular preure without producing cataract i beneficial. Becaue not all untreated patient progreed, the natural hitory of normal-tenion glaucoma mut be conidered before embarking on intraocular preure reduction with therapy apt to exacerbate cataract formation unle normal-tenion glaucoma threaten eriou viual lo.
