Abstract
Abstract: :
Purpose: To evaluate the risk of progression of normal–tension glaucoma suspects. Methods: A retrospective chart review involving 171 subjects identified initially as normal–tension glaucoma suspects and followed for more than 6 months for progression to normal–tension glaucoma. The definition of a normal–tension glaucoma suspect included measurements of intraocular pressure less than 21 mmHg, with the exception of one episode of elevated IOP, but less than 24 mmHg. Reasons for suspicion of glaucoma included increased cup–to–disc ratio (0.5 or greater) or asymmetric cup–to–disc ratio (0.1 or greater difference). Progression to normal–tension glaucoma was defined as either a change in diagnosis or a decision to initiate ocular hypotensive treatment. Results: 16 of 171 (9.4%) subjects progressed from suspects. 155 of 171 (90.6%) remained suspects. Two of the 16 progressors developed increased intraocular pressure at a later point in time and were classified as primary open angle glaucoma. Of the 16 progressors, only one was not placed on treatment. Among risk factors considered, the initial cup–to–disc ratio was found to be a risk factor for progression. The Kaplan Meier survival estimate for progression to normal–tension glaucoma was 10.9% at 5 years and 17.3% at 10 years after diagnosis, and was essentially the same for the two definitions of progression. Conclusions: In this study population, 10.9% subjects at 5 years and 17.3% at 10 years, progressed from normal–tension glaucoma suspects to having visual field changes, disc hemorrhages on examination or hypotensive treatment initiated. We conclude that the initial cup–to–disc ratio is an important risk factor for progression of normal–tension glaucoma suspects.
Keywords: clinical (human) or epidemiologic studies: risk factor assessment