Validated prediction model for the development of primary open-angle glaucoma in individuals with ocular hypertension

Objective To test the validity and generalizability of the Ocular Hypertension Treatment Study (OHTS) prediction model for the development of primary open-angle glaucoma (POAG) in a large independent sample of untreated ocular hypertensive individuals and to develop a quantitative calculator to estimate the 5-year risk that an individual with ocular hypertension will develop POAG. Design A prediction model was developed from the observation group of the OHTS and then tested on the placebo group of the European Glaucoma Prevention Study (EGPS) using a z statistic to compare hazard ratios, a c statistic for discrimination, and a calibration \u3c72 for systematic overestimation/underestimation of predicted risk. The 2 study samples were pooled to increase precision and generalizability of a 5-year predictive model for developing POAG. Participants The OHTS observation group (n = 819; 6.6 years\u2019 median follow-up) and EGPS placebo group (n = 500; 4.8 years\u2019 median follow-up). Testing Data were collected on demographic characteristics, medical history, ocular examination visual fields (VFs), and optic disc photographs. Main Outcome Measure Development of reproducible VF abnormality or optic disc progression as determined by masked readers and attributed to POAG by a masked end point committee. Results The same predictors for the development of POAG were identified independently in both the OHTS observation group and the EGPS placebo group\u2014baseline age, intraocular pressure, central corneal thickness, vertical cup-to-disc ratio, and Humphrey VF pattern standard deviation. The pooled multivariate model for the development of POAG had good discrimination (c statistic, 0.74) and accurate estimation of POAG risk (calibration \u3c72, 7.05). Conclusions The OHTS prediction model was validated in the EGPS placebo group. A calculator to estimate the 5-year risk of developing POAG, based on the pooled OHTS\u2013EGPS predictive model, has high precision and will be useful for clinicians and patients in deciding the frequency of tests and examinations during follow-up and advisability of initiating preventive treatment

Untreated 24-h intraocular pressures measured with Goldmann applanation tonometry vs nighttime supine pressures with Perkins applanation tonometry

AIMS: To compare supine nighttime intraocular pressure measurements with Perkins applanation tonometry to 24-h sitting intraocular pressures with Goldmann applanation tonometry. METHODS: A prospective, untreated, uncontrolled, observational cohort of qualified consecutive ocular hypertensive or primary open-angle glaucoma patients. Patients underwent sitting intraocular pressure measurements over 24-h by Goldmann and patients had their supine nighttime intraocular pressure measurements by Perkins. RESULTS: In 100 completed patients, the mean intraocular pressure at 1000, 2200, 0200 and 0600 hours while sitting was 22.5+/-3.7 mm Hg, and in the supine position, 23.5+/-4.3 mm Hg (P<0.001). The mean sitting Goldmann intraocular pressures across the three daytime points was 23.3+/-3.4 mm Hg and across three nighttime points was 21.5+/-4.0 mm Hg (P<0.001). In contrast, the mean daytime sitting Goldmann intraocular pressure was not different than the mean nighttime supine intraocular pressure evaluated with Perkins (22.8+/-4.4 mm Hg, P=0.07). However, only 70% of patients were within 1.0 mm Hg of the highest daytime reading for all nighttime supine and sitting intraocular pressures. CONCLUSION: This study suggests that with Perkins applanation tonometry the untreated mean supine intraocular pressures are not higher at night than daytime sitting Goldmann applanation tonometry. However, the highest daytime sitting intraocular pressure measurement does not consistently predict the highest nighttime sitting or supine intraocular pressure valu