MEANS FOR CONTROLLING THE PROGRESSION OF MYOPIA

摘要

A contact lens (10) for use in controlling or retarding the progression o f myopia in an eye has a central optical zone (20) approximating the normal diameter of the pupil of the eye (22) that gives clear central vision at dis tance for the wearer. An annular peripheral optical zone 24 that is substant ially outside the diameter of the pupil is formed around the central optical zone (20) with greater refractive power than that of the central zone (22) so that oblique rays entering the eye through the peripheral optical zone (2 4) will be brought to focus at a focal plane that is substantially on or ant erior to the peripheral region of the retina. Preferably, the rear surface ( 16) of the lens is shaped to conform to the cornea of the eye and the front surface (18) of the lens (10) is shaped to provide - in conjunction with the rear surface (16) - the desired optical properties of the central and perip heral optical zones. The front surface (18) is also preferably contoured to form a smooth transition (30) between the junction of the central optical zo ne (20) and the peripheral optical zone (24), with or without designed optic al properties such as progressive power.