The Houston myopia control study: a preliminary report by the patient care team.

The Houston Myopia Control Study is a 3-year randomized clinical trial designed to test the efficacy of bifocal lenses for the control of myopia. Each of 213 myopic subjects, between the ages of 6 and 15 years, was placed in either a single vision (standard treatment) group, a +1.00 D. add group, or a +2.00 D. add group, by means of a table of random numbers. Subjects in each of the 3 groups were matched on the basis of sex, age, and the amount of myopia. Subjects were accepted into the study during an 18-month period ending in September, 1982, so all subjects will have completed the study by September, 1985. The purpose of this preliminary report is to inform optometrists of the existence of the study and to discuss the factors that must be taken into consideration when designing a randomized clinical trial making use of bifocal lenses for the control of myopia.