To provide the results of the Early Manifest Glaucoma Trial, which compared the effect of immediately lowering the intraocular pressure (IOP), vs no treatment or later treatment, on the progression of newly detected open-angle glaucoma. Design: Randomized clinical trial. Participants: Two hundred fifty-five patients aged 50 to 80 years (median, 68 years) with early glaucoma, visual field defects (median mean deviation, −4 dB), and a median IOP of 20 mm Hg, mainly identified through a population screening. Patients with an IOP greater than 30 mm Hg or advanced visual field loss were ineligible.

No abstract

EMGT treatment reduced progression risk in half, demonstrating the value of IOP lowering in early glaucoma. Age and indicators of disease severity also predicted progression.

Setting/Participants: Two hundred fifty-five openangle glaucoma patients randomized to argon laser trabeculoplasty plus topical betaxolol or no immediate treatment (129 treated; 126 controls) and followed up every 3 months. Methods: Progression was determined by perimetric and photographic optic disc criteria. Patient-based risk of progression was evaluated using Cox proportional hazard regression models and was expressed as hazard ratios (HR) with 95% confidence intervals (95% CI). Results: After 6 years, 53% of patients progressed. In multivariate analyses, progression risk was halved by treatment (HR = 0.50; 95% CI, 0.35-0.71). Predictive baseline factors were higher intraocular pressure (IOP) (ie, the higher the baseline IOP, the higher the risk), exfoliation, and having both eyes eligible (each of the latter 2 factors doubled the risk), as well as worse mean deviation and older age. Progression risk decreased by about 10% with each millimeter of mercury of IOP reduction from baseline to the first follow-up visit (HR=0.90 per millimeter of mercury decrease; 95% CI, 0.86-0.94). The first IOP at that visit (3 months' follow-up) was also related to progression (HR = 1.11 per millimeter of mercury higher; 95% CI, 1.06-1.17), as was the mean IOP at follow-up (HR=1.13 per millimeter of mercury higher; 95% CI, 1.07-1.19). The percent of patient follow-up visits with disc hemorrhages was also related to progression (HR=1.02 per percent higher; 95% CI, 1.01-1.03). No other factors were identified. Conclusions: Patients treated in the EMGT had half of the progression risk of control patients. The magnitude of initial IOP reduction was a major factor influencing outcome. Progression was also increased with higher baseline IOP, exfoliation, bilateral disease, worse mean deviation, and older age, as well as frequent disc hemorrhages during follow-up. Each higher (or lower) millimeter of mercury of IOP on follow-up was associated with an approximate 10% increased (or decreased) risk of progression.

To date, there has been a lack of evidence-based guidance on the frequency of visual field examinations required to identify clinically meaningful rates of change in glaucoma. The objective of this perspective is to provide practical recommendations for this purpose. The primary emphasis is on the period of time and number of examinations required to measure various rates of change in mean deviation (MD) with adequate statistical power. Empirical data were used to obtain variability estimates of MD while statistical modelling techniques derived the required time periods to detect change with various degrees of visual field variability. We provide the frequency of examinations per year required to detect different amounts of change in 2, 3 and 5 years. For instance, three examinations per year are required to identify an overall change in MD of 4 dB over 2 years in a patient with average visual field variability. Recommendations on other issues such as examination type, strategy and quality are also made.