The 12-year Incidence of Glaucoma and Glaucoma-related Visual Field Loss in Italy

Abstract

To assess the 12-year incidence of glaucoma and glaucoma-related visual field loss in a population-based cohort study. In 2000, we reexamined 411 of the 581 survivors from the original Ponza eye study conducted in 1988. Primary open-angle (POAG), primary angle-closure (PACG), and secondary [pseudoexfoliative (PEX)] glaucoma were diagnosed according to the 3-tiered system of evidence developed by the International Society of Geographical and Epidemiological Ophthalmology. Severity of glaucoma was classified according to the Bascom-Palmer system. Visual loss was defined according to World Health Organization guidelines. Relative risk ratios were calculated for several variables. The 12-year incidence of definite POAG was 3.8% (95% confidence intervals (CI), 2.3-6.2), that is, an average annual rate of 0.32%. Corresponding rates for PACG and PEX glaucoma were 0.5% (95% CI, 0.1-1.8) and 0.8% (95% CI, 0.3-2.2), respectively. Half the incident glaucoma cases (45%) had not been diagnosed earlier. Fifty-five percent of the incident POAG eyes had Bascom-Palmer stage 1 or 2 disease and 40% of the incident PACG or PEX glaucoma eyes had stage 3 or 4 disease. Seven of 20 incident glaucoma cases presented with monocular or binocular visual loss because of advanced visual field loss. Significant risk factors for POAG included high myopia (>6.0 D), intraocular pressure ≥22 mm Hg, and glaucoma family history. The average annual incidence of definite POAG in Ponzas lower than that reported in persons of African ancestry and higher than that observed in certain other white populations.