Clinical Refraction, Accommodation, Refractive Errors, and Astigmatism

Abstract

Clinical refraction is a fundamental component of ophthalmic practice and optometric  assessment because it provides an objective and subjective evaluation of the optical status of the  eye and determines the appropriate refractive correction. Clear vision depends on the precise  interaction between the cornea, crystalline lens, aqueous and vitreous media, retina, and neural  visual pathways. Among these structures, the cornea and crystalline lens provide most of the eye's  refractive power, while accommodation enables the eye to maintain clear retinal images when  viewing objects at different distances. Disturbances in the optical system result in refractive errors,  including myopia, hyperopia, and astigmatism.