Survey on Visual Impairment and Refractive Errors on Ta'u Island, American Samoa

To assess the prevalence of presenting visual impairment and refractive errors on the isolated island of Ta'u, American Samoa.

Presenting visual acuity and refractive errors of 124 adults over 40 years of age (55 male and 69 female) were measured using the Snellen chart and an autorefractometer. This sample represented over 50% of the island's eligible population.

In this survey, all presenting visual acuity (VA) was uncorrected. Of the included sample, 10.5% presented with visual impairment (visual acuity lower than 6/18, but equal to or better than 3/60 in the better eye) and 4.8% presented with VA worse than 6/60 in the better eye. Overall, 4.0% of subjects presented with hyperopia (+3 D or more), 3.2% were myopic (-1 D or less), and 0.8% presented with high myopia (-5 D or less). There was no significant difference between genders in terms of visual impairment or refractive errors.

This study represents the first population-based survey on presenting visual acuity and refractive errors in American Samoa. In addition to providing baseline data on vision and refractive errors, we found that the prevalence of myopia and hyperopia was much lower than expected.