Autorefractometry (autorefraction, objective refraction) or “computerized eye examination.” Special strips (rulers) or a Hess wheel with lenses of different powers embedded in them are used for the test. In order to perform the test, it is necessary to pharmacologically electrocute the ciliary muscle responsible for accommodation. For autorefractometry used in routine eye examinations prior to the selection of corrective eyeglasses/contact lenses, most often accommodative abolition medication is not administered, but it can be done if needed.

Autorefractometry is not only performed as part of a routine ophthalmic examination, but is also included in “diagnostic packages” for such defects and conditions as strabismus and large inconsistency (astigmatism). The examination is also carried out before vision correction procedures (laser, surgical).

The principle of the autorefractometer is based on the completely painless and harmless entry of a beam of infrared radiation into the eye and analysis of the reflections of this beam reflected from its structures. The reflexes are processed by a computer processor, which generates data that tells the patient’s refractive defect. The test is very comfortable: the measurement for each eye takes only a few seconds, and the examinee only has to look through a small opening, where he or she sees a photograph depicting some distant object.

The result of the test, importantly, is indicative, which means that no prescription for corrective glasses or corrective contact lenses may be issued solely after a “computer vision test.” This can lead to complete rejection of the correction by the eye: there may be a sensation of a slight distortion of space (especially visible under the feet in the form of a sloping floor) or a floating image, as well as dizziness and headaches, eye pain and even nausea, which do not pass after a few days – and that’s how long the brain needs to get used to new glasses.

When measuring visual defects in qualifying for laser correction, it is important to take measurements with an autorefractometer after the patient has been administered drops that dilate the pupil and paralyze (disable) accommodation. This allows the comparison of the patient’s defect after excluding accommodation with the defect obtained subjectively in a full refraction test. This is, of course, not the only test performed as part of the diagnosis before laser vision correction. You can read more about diagnostic testing here and here: