Table 2.

Estimates of the prevalence of visual impairment

Study	Setting	N	Age	VA	Testing conditions	Prevalence
Klein et al, 1991	Beaver Dam, USA	4926	43–54	≤6/12->6/60	Best corrected better eye	0.7%
			55–64			0.7%
			65–74			4.7%
			75+			19.1%
Gunnlaugsdottir et al 2008	Reykjavik, Iceland	1045	>50–80+	<6/18	Best corrected, better eye	0.96%
				<6/12		2.01%
			50–59	<6/18		0%
				<6/12		0.28%
			>80	<6/18		7.9%
				<6/12		11.80%
Buch et al 2004	Copenhagen, Denmark	9980	20–39	<6/12->6/60	Best corrected, better eye	0.13%
			20–64			0.25%
			65–84			2.24%
			80–84			8.29%
Tielsch et al1990	Baltimore, US	2490	40–59	<6/18–0.5/60	Best corrected, better eye	0.17% Caucasians
						0.83% Blacks
Taylor et al, 1997	Melbourne, Australia	3268	40–90+	<6/12-≥6/18	Habitual, better eye	2.6%
				<6/18-≥6/60		0.92%
				<6/60-≥3/60		0.21%
				<6/12-≥6/18	Best corrected, better eye	0.61%
				<6/18-≥6/60		0.43%
				<6/60-≥3/60		0.15%
Robinson et al 2013	Ontario, Canada	768	39–94	<6/7.5 (0.1 logMAR)	Habitual, better eye (weighted prevalence)	15.2%
				<6/12 (0.3 logMAR)		2.7%
Khawaja et al 2013	Norwich, UK	8563	48–92	<6/10 (0.22 logMAR)	Habitual, better eye (weighted prevalence)	5.65%
				<6/18 (0.48 logMAR)		0.55%