PMMA lenses worn for twenty years

In this study of 150 eyes (75 patients) wearing PMMA lenses for at least twenty years, most patients experienced only small change in corneal curvature. Some developed with-the-rule astigmatism, but 27% showed no variations in corneal toricity, although a refractive change of +/- 3.00 D was observed. 40 eyes had no difference of cylinder Rx and 13 maintained the same spherical correction. Graphs indicate a limited spread of statistically significant changes in the corneal curvature. Complete information on corneal integrity is not included in this study but biomicroscopic examination did not disclose any serious adverse conditions in the opinion of the authors.