Prevalences of astigmatism and anisometropia in adult danes. With reference to presbyopes' possible use of supermarket standard glasses.

A report is given of astigmatism and anisometropia prevalences in an adult hospital sample considered refractively unselected. Astigmatism of at least 0.75 cyl value (by subjective trial) appeared in 20% (n = 600), or in 16% of all eyes (some cases being unilateral). Twenty per cent of astigmatic eyes had an oblique axis. Inverse astigmatism (against rule) showed increasing frequency with age. In a sample analysed for anisometropia (n = 1.200) 9% had a side difference of 1 D or more, while 75% had strict isometropia. Eyes with astigmatism and anisometropia are grouped mainly towards the ametropic ends of the refractive distribution curve, away from emmetropia. The data are used for assessing to what extent the presbyopic population can expect benefit from some newly introduced supermarket standard reading-glasses (+1 to +4 D). Probably, about two thirds can use them. Having had a tradition of individual prescription in our country, the offer of standard glasses without professional trial may eventually result in fewer ophthalmic disorders being diagnosed 'by chance'.