THE EFFECT OF CONTACT LENS DIAMETER AND POWER ON FLEXURE AND RESIDUAL ASTIGMATISM

Contact lens flexure and the associated residual astigmatism were measured, with hard (PMMA) corneal lenses of various diameters and powers, on corneas of various toricities. Varying contact lens diameter did not alter lens flexure or residual astigmatism on any of the corneas. Varying the contact lens power did not alter lens flexure or residual astigmatism on spherical corneas. However, on toric corneas, contact lenses with higher minus power caused significantly less flexure and residual astigmatism than did contact lenses with lower minus power.