OBJECTIVE

To evaluate the predictive factors of open-angle glaucoma (OAG) in patients affected by ocular hypertension enrolled in the European Glaucoma Prevention Study (EGPS).

DESIGN

Randomized, double-masked, controlled clinical trial.

PARTICIPANTS

One thousand seventy-seven patients, > or =30 years old, were enrolled at 18 European centers. The patients met inclusion criteria: intraocular pressure, 22 to 29 mmHg; 2 normal and reliable visual fields (VFs) (on the basis of mean deviation and corrected pattern standard deviation [PSD]); and a normal optic disc, as determined by an optic disc reading center.

INTERVENTION

Treatment with dorzolamide or a placebo (the vehicle of dorzolamide) in one or both eyes.

MAIN OUTCOME MEASURES

Efficacy end points were VF and/or optic disc changes. Baseline demographic and clinical data were collected before randomization, except for corneal thickness measurements, which were determined during follow-up. Proportional hazards models were used to identify factors that predicted which participants in the EGPS had developed OAG.

RESULTS

In multivariate analyses, factors that predicted the development of OAG included older age (hazard ratio [HR], 1.32; 95% confidence interval [CI], 1.04-1.69), larger vertical cup-to-disc (C/D) ratio (HR, 1.34; 95% CI, 1.14-1.58), larger vertical C/D ratio asymmetry (HR, 1.46; 95% CI, 1.11-1.93), higher PSD (HR, 1.66; 95% CI, 1.15-2.38), and lesser central corneal thickness (HR, 1.32; 95% CI, 1.05-1.67).

CONCLUSIONS

Baseline age, vertical C/D ratio, vertical C/D ratio asymmetry, and PSD were good predictors of the onset of OAG in the EGPS. Central corneal thickness was found to be a powerful predictor of the development of OAG. The EGPS results agree with the findings of the Ocular Hypertension Treatment Study and support the need for a thorough evaluation of patients with ocular hypertension.