Contact lens effects on ametropia: a current example of the clinical trial

This paper describes the basic features of an ongoing double masked, randomized, controlled clinical trial which studies the changes in corneal and visual function that result when contact lenses are fitted in a manner designed to alter myopic refractive error. Subjects are randomly allocated to either a treatment or control group. Corneal and visual changes resulting from wearing lenses of these designs are compared to the effects of wearing contact lenses fitted in a standard clinical manner. Comparative analysis of the treatment and control groups is based on (1) visual acuity, (2) refractive error, (3) corneal thickness, (4) endothelial cell density, (5) external eye health, (6) corneal curvature, (7) duration of effect, and (8) predictive factors such as ocular rigidity and corneal topography. Essential parts of the experimental design and some results from the first phase of the study are reported.