The 12-year Incidence of Glaucoma and Glaucoma-related Visual Field Loss in Italy: The Ponza Eye Study

Purpose: To assess the 12-year incidence of glaucoma and glaucoma-related visual field loss in a population-based cohort study. Patients: In 2000, we reexamined 411 of the 581 survivors from the original Ponza eye study conducted in 1988. Methods: 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. Results: 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 >= 22mm Hg, and glaucoma family history. Conclusion: 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.