Elsevier

Ophthalmology

Volume 110, Issue 3, March 2003, Pages 584-588
Ophthalmology

Incidence of blindness and low vision in a sample population: The Priverno Eye Study, Italy

https://doi.org/10.1016/S0161-6420(02)01898-5Get rights and content

Abstract

Purpose

To study the incidence of blindness and low vision over a 7-year period.

Design

Population-based cohort study.

Participants

The survivors of the original cohort of 860 persons from Priverno, Italy, aged 45 to 69 years, were reexamined. Of the 760 eligible survivors, 619 (81.4%) had a 7-year follow-up visit.

Methods

Baseline and follow-up examinations included the collection of anamnestic and ophthalmologic data by the same observers using the same methods and classification criteria to minimize sources of variability.

Main outcome measures

Best-corrected visual acuity (VA) measured at 4 m by standardized logarithmic chart was expressed as the logarithm of the minimum angle of resolution (logMAR). World Health Organization definitions of blindness and low vision were adopted (respectively, VA > 1.3 logMar and VA > 0.6 to 1.3 logMar in the better eye or in either eye). Participants at risk for visual impairment were those without blindness or low vision in one or both eyes at baseline; participants at risk for one-eye visual impairment were those without blindness or low vision in both eyes at baseline.

Results

A total of 33 participants were defined as incident cases of visual impairment. The overall incidence figures for blindness, low vision, one-eye blindness, and one-eye low vision were respectively 0.2% (95% confidence interval [CI], 0.0–0.9), 1.3% (95% CI, 0.7–2.6), 1.2% (95% CI, 0.6–2.4), and 2.9% (95% CI, 1.8–4.6).

Conclusions

This study provides population-based estimates of the incidence of visual impairment in an adult, free-living European population. With respect to the younger participants, older subjects at baseline were at higher risk for incident visual impairment, the main causes of which were cataract, myopia, and diabetic retinopathy. The incidence of visual impairment in the subgroup aged 55 to 64 years at baseline was significantly higher than that found in Beaver Dam 5-year study and similar to that found in Beaver Dam 10-year Study, when the same definitions were adopted. This difference may be partially explained by social and cultural habits of the female samples, but many other factors may play a role.

Section snippets

Material and methods

Between September and November 1987, standardized ophthalmologic examinations were performed on 860 adults (376 men, 484 women) from the community of Priverno, Italy, a town of 30,000 located 150 km from Rome. The study population was drawn from members of the community already enrolled in the Di. S. Co Project, a population-based study of cardiovascular risk factors. Persons eligible were contacted by a letter describing the objectives of the study and the methods to be used. Informed consent

Results

As shown in Table 1, of the 860 subjects who took part in the original 1987 study, 44 had died at the time of the follow-up examination, and 56 were no longer living in Priverno. Of the remaining 760 eligible subjects, 141 did not participate in the follow-up: 49 (34.8%) for health reasons; 32 (22.7%) because of their work; 33 (23.4%) for family-related reasons; and 27 (19.1%) because of unspecified factors. There was no significant difference between the number of males and the number of

Discussion

To our knowledge, the Priverno Eye Study is the first attempt to estimate the incidence of blindness and low vision (defined according to World Health Organization criteria) in an adult free-living population in Europe. It is difficult to classify the incidence of visual impairment observed in this study as “high” or “low.” The increase in the overall presence of visual impairment during the 7-year follow-up is certainly substantial (from 4.7% to 8.6%). It is also possible that our incidence

References (9)

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Manuscript no. 210995.

Research developed within the Target Project “FATMA” (Prevention and Control of Risk Factors), Sub-Project “Community Medicine” of the C.N.R. (Consiglio Nazionale delle Ricerche), 1990–1995, Grant no. 91.00119.PF41.

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