Refractive Error - Diagnosis

Diagnosis

Blurry vision may result from any number of conditions not necessarily related to refractive errors. The diagnosis of a refractive error is usually confirmed by an eye care professional during an eye examination using an instrument called a phoropter which contains a large number of lenses of varying optical power. In combination with a retinoscope (a procedure entitled retinoscopy), the doctor instructs the patient to view an eye chart while he or she changes the lenses within the phoropter to objectively estimate the amount of refractive error the patient may possess. Once the doctor arrives at an estimate, he or she typically shows the patient lenses of progressively higher or weaker powers in a process known as refraction or refractometry. Cycloplegic agents are frequently used to more accurately determine the amount of refractive error, particularly in children

An automated refractor is an instrument that is sometimes used in place of retinoscopy to objectively estimate a person's refractive error. Shack–Hartmann wavefront sensor and its inverse can also be used to characterize eye aberrations in a higher level of resolution and accuracy.

Vision defects caused by refractive error can be distinguished from other problems using a pinhole occluder, which will improve vision only in the case of refractive error.