Detection of glaucoma progression by perimetry and optic disc photography at different stages of the disease: results from the Early Manifest Glaucoma Trial

PURPOSE To compare the earliest detection of progression in visual fields and monoscopic optic disc photographs at different stages of manifest glaucoma. METHODS This study evaluated 306 eyes in 249 patients with manifest open-angle glaucoma included in the Early Manifest Glaucoma Trial (EMGT). All patients in the trial were followed up regularly by standard automated perimetry and monoscopic optic disc photography, and the median follow-up time was 8 years. Progression was assessed in series of optic disc photographs and in series of visual fields using glaucoma change probability maps and the predefined EMGT progression criterion. The proportion of progressions detected first in visual fields and the proportion detected first in optic disc photographs were compared at different stages of glaucoma severity defined by the perimetric mean deviation (MD) of the baseline visual field. RESULTS Assessment of 210 eyes with early visual field loss, 83 eyes with moderate field loss, and 13 eyes with advanced field loss showed that, among the eyes exhibiting progression, the progression was detected first in the visual field in 80%, 79% and 100%, respectively. The predominance of visual field progressions at all stages was still apparent when using narrower (3-dB) MD intervals for staging. CONCLUSION In the EMGT material on eyes with manifest open-angle glaucoma, the initial progression was detected much more often in the visual field series than in the optic disc photographs at all stages of disease.