Refraktionsbestimmungen

Refraktionsbestimmung, commonly referred to as refraction, is the process of measuring an individual's refractive error and determining the lens power needed to achieve best visual clarity. It is performed by eye care professionals to produce a corrective prescription for glasses or contact lenses and to guide plans for refractive surgery when appropriate.

The procedure typically includes objective and subjective components. Objective refraction uses devices such as an autorefractor or retinoscope to estimate the eye’s focusing power without relying on patient responses. Subjective refraction involves the patient’s feedback while the practitioner applies different lens options in a phoropter or trial frame to identify the combination that yields the sharpest, most comfortable vision. Binocular balancing may be performed to ensure comfortable, coordinated vision at near and distance.

Measured refractive errors are expressed in diopters and described by spherical power (S or sphere), cylindrical power (C or cylinder) for astigmatism, and axis (A) indicating the orientation of the astigmatism. A prescription may be written as a combination such as sphere, cylinder, and axis (for example, -2.50 DS / -0.75 DC at 180).

Common refractive conditions include myopia (nearsightedness), hyperopia (farsightedness), astigmatism, and presbyopia (age-related loss of near focus). Refraction also considers accommodation, pupil size, and ocular health. Limitations exist, as measurements reflect potential correction under examination conditions and may require adjustment over time. The results guide corrective devices, monitor visual performance, and support planning for surgical options when indicated.