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.

ABSTRACT.Aims: The Early Manifest Glaucoma Trial (EMGT) (316 eligible eyes) has used a new set of criteria to define visual field progression in glaucoma. This paper provides estimates of the amount of visual field worsening required to reach the EMGT definition of definite perimetric progression. Methods: In the 148 eyes that reached definite progression, we first determined changes between baseline and the time of definite EMGT progression, both for mean deviation (MD) and for number of highly (p < 0.5%) significantly depressed test points in pattern deviation probability maps. Second, we studied whether such changes depended on baseline MD, intraocular pressure (IOP), age and time to progression, all of which are factors that affect the rate of field progression. Results: In eyes reaching progression, the mean change in MD from baseline was À1.93 dB (SE AE 0.20) and the mean change in number of significant points was þ4.85 (SE AE 0.35). These changes did not show linear dependency on baseline MD, IOP or time to progression. Conclusions: The average amount of field deterioration needed to reach EMGT visual field progression has been measured and expressed in more conventional units (i.e. a loss of about À 2dB in MD and an increase in about five highly significant points). These estimates will facilitate the clinical interpretation of the results of EMGT.

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