Abstract: A rigid corneal contact lens comprises a front-surface optical zone and a back-surface optical zone: the front-surface optical zone comprises a front-surface central zone (1) and a defocusing zone (2) at the periphery of the front-surface central zone (1); the front-surface central zone (1) is spherical; the defocusing zone (2) has a radius of curvature decreasing from the outside of the front-surface central zone (1) continuously and a minimum radius of curvature which ranges from 95% to 50% of the radius of curvature of the front-surface central zone (1). Because of the structure of a human eye, the phenomenon of peripheral hyperopic defocus exist in human eyes, that is, central image points for an image are projected on macula foveal of retina and peripheral image points are projected behind retina. As shown in experimental evidences, peripheral hyperopic defocus is the main cause of myopia development which can be moderated by restraining peripheral hyperopic defocus.

Abstract: A rigid corneal contact lens comprises a front-surface optical zone and a back-surface optical zone: the front-surface optical zone comprises a front-surface central zone (1) and a defocusing zone (2) at the periphery of the front-surface central zone (1); the front-surface central zone (1) is spherical; the defocusing zone (2) has a radius of curvature decreasing from the outside of the front-surface central zone (1) continuously and a minimum radius of curvature which ranges from 95% to 50% of the radius of curvature of the front-surface central zone (1). Because of the structure of a human eye, the phenomenon of peripheral hyperopic defocus exist in human eyes, that is, central image points for an image are projected on macula foveal of retina and peripheral image points are projected behind retina. As shown in experimental evidences, peripheral hyperopic defocus is the main cause of myopia development which can be moderated by restraining peripheral hyperopic defocus.