silmälasireseptin

Silmälasiresepti, known in English as an eyeglass prescription, is a document issued by an optometrist or ophthalmologist that specifies the corrective lenses needed to improve a patient's vision. This prescription details the precise measurements required to create lenses that address refractive errors such as myopia (nearsightedness), hyperopia (farsightedness), astigmatism, and presbyopia.

The prescription typically includes several key components. Sphere (SPH) indicates the degree of nearsightedness or farsightedness. A negative value signifies myopia, while a positive value indicates hyperopia. Cylinder (CYL) and Axis are used to correct astigmatism, which is a condition where the eye's cornea or lens has an irregular shape. The CYL value denotes the amount of astigmatism, and the Axis indicates its orientation, measured in degrees.

Additionally, a prism correction might be included if there is a misalignment of the eyes (strabismus or phoria), to help the eyes work together. The Base indicates the direction of the prism. For bifocal or progressive lenses, a "ADD" value is specified, representing the additional magnifying power needed for reading or close-up tasks, typically for individuals with presbyopia.

The prescription also often includes the pupillary distance (PD), which is the distance between the centers of the pupils of the eyes. This measurement is crucial for ensuring the optical center of the lenses is properly aligned with the wearer's eyes, optimizing vision and comfort. An eyeglass prescription is valid for a specific period, after which a new eye examination is usually recommended to ensure the prescription remains accurate.