Visual acuity in a prison population

I determined the best corrected acuity of 90 prisoners. The data were compared to available published visual acuity data for the general population and to 6/6 (20/20) as the assumed normal. The prison population differed significantly from the population analyzed in one reported study but not from that in another (p less than 0.05). Comparison to the assumed normal of 6/6 showed no statistical difference. The differences among the studies are discussed. The data suggest that for this population corrected visual acuity may not be dissimilar from that of the general population.