Abstract
Purpose:
To identify predictors of short-term intraocular pressure (IOP) reduction following selective laser trabeculoplasty (SLT) in Afro-Caribbean eyes with primary open-angle glaucoma (POAG).
Methods:
In a prospective cohort study, sixty-one St. Lucians of African descent with POAG underwent washout of IOP-lowering drugs followed by bilateral 360 degree SLT. Subjects were re-examined 1 hour, 1 week, 1 month after SLT and then every three months thereafter. IOP was measured by a single examiner using a Perkins tonometer. Short-term IOP response to SLT was defined as the average of IOP readings at months 1 and 3. Putative predictors of this outcome variable included age, gender, prior IOP-lowering medication use (prostaglandin analogues versus all others), baseline IOP, central corneal thickness, cup-disc ratio, and total laser power applied to the eye. A linear regression model was built by first assessing each putative predictor in univariate analysis; those with p<0.1 were included in the multivariate analysis. Right eyes were analyzed primarily; results were confirmed in left eyes.
Results:
Mean IOP in 61 right eyes dropped from 21.4 mmHg before SLT to 13.5 mmHg and 14.0 mmHg at 1 and 3 months post-treatment. Univariate predictors of IOP response (p<0.1) included baseline IOP and age. In a multivariate model, both baseline IOP (beta=0.444, p<0.0001) and age (beta=0.0754, p=0.0341) were significant; the model explained less than a third of the total variance (r-squared = 0.32). Results in left eyes were identical.
Conclusions:
Baseline IOP and age are significant predictors of IOP response to SLT in Afro-Caribbeans with POAG, although together they account for only a small proportion of the variability in IOP response.
Keywords: 578 laser •
568 intraocular pressure