Long-term Impact of Immediate Versus Delayed Treatment of Early Glaucoma: Results From the Early Manifest Glaucoma Trial

Abstract

To compare long-term visual outcomes in the 2 arms of the Early Manifest Glaucoma Trial (EMGT) and determine if delayed treatment was associated with a penalty in terms of visual function. Long-term follow-up of a prospective, randomized controlled clinical trial. EMGT was carried out at 2 centers in Sweden; 255 subjects with newly detected, untreated glaucoma were randomized to immediate treatment with topical betaxolol and argon laser trabeculoplasty or to no initial treatment as long as no progression was detected. Subjects were followed prospectively with standard automated perimetry, visual acuity measurements, and tonometry for up to 21 years. Outcomes included vision impairment (VI), the perimetric mean deviation (MD) index and rate of progression, and visual acuity. At study end, percentages of eyes with VI or blindness were slightly higher in the treated group than in the untreated control group, 12.1% vs 11.0%, and 9.4.% vs 6.1% respectively, as were subjects with VI in at least one eye, 19.5% vs 18.7%. The differences were not statistically significant, nor were cumulative incidences of VI in at least one eye. The control group had more field loss than the treatment group, with median MD in the worse eye of -14.73 dB vs -12.85 dB, and rate of progression of -0.74 vs -0.60 dB/y, which was not statistically significant. Differences in visual acuity were minimal. Delaying treatment did not result in serious penalties. VI occurred at similar proportions in both treatment arms with a slight preponderance in the treatment group, whereas visual field damage was slightly higher in the control group.