Effect of Peripheral Defocus on Axial Eye Growth and Modulation of Refractive Error in Hyperopes: Protocol for a Nonrandomized Clinical Trial (Preprint)

Abstract

Background: Hyperopia occurs due to insufficient ocular growth and a failure to emmetropise in childhood. In anisohyperopia, it is unclear why one eye may remain hyperopic while the fellow eye grows towards an emmetropic state. Animal work has shown that manipulating peripheral defocus through optical means while simultaneously providing correct axial focus can either discourage or encourage axial eye growth to effectively treat myopia or hyperopia, respectively. The progression of myopia and axial eye growth can be significantly reduced in children and adolescents through the use of multifocal contact lenses. These contact lenses correct distance central myopia while simultaneously imposing relative peripheral myopic defocus. The effect of correcting distance central hyperopia while simultaneously imposing relative peripheral hyperopic defocus is yet to be elucidated in humans. Objectives: To understand the natural progression of axial eye growth and refractive error in hyperopes and anisohyperopes; to establish if axial eye growth and refractive error can be modified using multifocal contact lenses in hyperopes and anisohyperopes.