Keratometric readings on 132 different eyes were examined from the patient records. Sixty eyes had previously worn polymethyl methacrylate (PMMA) lenses and then were refitted with the Boston II gas-permeable contact lens. The remaining 72 eyes had never worn contact lenses and these too were fitted with the Boston II lens. The Boston II contact lens is a nonhydrophilic contact lens composed of methylmethacrylate-dimethylitaconate-siloxanyl copolymer with a reported Dk value of 14.6 X 10(-11) ml O2 cm2/s ml mm Hg (35 degrees C). The mean and SD of the keratometric readings and the amount of corneal toricity found were calculated for each set of progress reports. The data in this study indicate that an alignment-fitting Boston II gas-permeable contact lens does not cause curvature changes in corneas during the first three months of wear.