Refraction of the Eye Ametropic

In ophthalmology, eye refraction (from Latin - “meeting”) is the totality of the refractive abilities of the tissues of the eyeball and cornea, which determine clear visual perception. The ability of the eye to determine the image visible to the eye through the optical properties of the retina and the optical system of the eye is called vision, this is the refractive ability of the eye.

Refraction serves as the basis for determining the optical power of the eye - a power that characterizes the ability to form a clear image on the retina and is measured in diopters (diptr). The focal power value determines the optical distance between the retina and the light source in the eye. This distance is called theoretical vision. The focus value corresponding to the visual perception of the eye is considered accommodation of the eye and is determined by the tension of the ciliary muscle. In a healthy eye, refraction is positive, i.e. rays from a distant point enter the macula, and from a close point they are scattered. When the eye is farsighted, a person sees poorly in the distance and sees perfectly well near. This refractive error is explained as an increase in negative refraction due to relaxation of the refractive apparatus (skiascopy anomaly), reduction in reserve accommodation (phenacismus), and lens deposition. To treat farsightedness, wearing glasses with diverging lenses is prescribed. Myopia is explained by overstraining the refractive power of the eye, the deposition of refractive layers - a film on the iris. Patients complain of headaches when working at close distances,