Objectives: The Early Manifest Glaucoma Trial (EMGT) will evaluate the effe
ctiveness of reducing intraocular pressure (IOP) in early, previously untre
ated open-angle glaucoma. Its secondary aims are to explore factors related
to glaucoma progression and to study the natural history of the disease. T
his article describes the EMGT design and presents baseline data.
Design: Randomized, clinical trial.
Participants: Newly diagnosed patients 50 to 80 years of age with early gla
ucomatous visual field defects were mainly identified from a population-bas
ed screening of more than 44,000 residents of Malmo and Helsingborg, Sweden
. Exclusion criteria were advanced visual field loss; mean IOP greater than
30 mmHg or any IOP greater than 35 mmHg; visual acuity less than 0.5; and
inability to complete follow-up protocols.
Interventions: After informed consent, patients were randomized to treatmen
t or no initial treatment with close follow-up. Treated patients had laser
trabeculoplasty and started receiving topical betaxolol twice daily in elig
ible eyes. Follow-up visits include computerized perimetry and tonometry ev
ery 3 months and fundus photography every 6 months. Decisions to change or
begin treatment are made jointly with the patient when EMGT progression occ
urs and also later if clinically needed.
Main Outcome Measures: The EMGT progression is defined by sustained increas
es of visual field loss in three consecutive C30-2 Humphrey tests, as deter
mined from computer-based analyses, or by optic disc changes, as determined
from flicker chronoscopy and side-by-side comparisons of fundus photograph
s performed by masked, independent graders.
Results: A total of 255 patients were randomized between 1993 and 1997 and
will be followed for at least 4 years. All had generally good health status
; mean age was 68.1 years, and 66% were women. At baseline, mean IOP was 20
.6 mmHg and 80% of eyes had IOP less than 25 mmHg,
Conclusions: The Early Manifest Glaucoma Trial is the first large randomize
d, clinical trial to evaluate the role of immediate pressure reduction, as
compared to no initial reduction, in patients with early glaucoma and norma
l or moderately elevated IOP, Its results will have implications for: (1) t
he clinical management of glaucoma; (2) understanding the role of IOP and t
he natural history of glaucoma; and (3) evaluating the rationale for glauco
ma screening.