Residual astigmatism and visual acuity with hydrogel contact lenses: a comparative study

Residual astigmatism, visual acuity, and transferred corneal toricity were measured in a double masked fashion on 24 randomly selected patients fitted with Buasch and Lomb Soflens contact lenses, the Hydrocurve II contact lenses, and the AOSoftTM hydrophillic contact lenses. None of the subjects had any contraindications to hydrogel lens wear. All three lens types produced a small but similar reduction in refractive astigmatism. However, because of residual astigmatism, fewer eyes achieved 20/20 or better visual acuity with each of the hydrogel lens types than with the best spectacle correction. Corneal toricity was found to be transferred to the front surface of all three lens types. Our findings indicate that generally these three types of hydrogel lenses result in similar residual astigmatism, visual acuity and transferred corneal toricity. However, individual differences may occur. Therefore, the choice of lens type should be based on the individual patient's response to various lens types.