Refraction is a topic covered in the Davis's Lab & Diagnostic Tests.

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To assess the visual acuity of the eyes in patients of all ages, to evaluate visual acuity as required by driver licensing laws, and to assist in evaluating the eyes prior to therapeutic interventions such as eyeglasses, contact lenses, low vision aids, cataract surgery, or laser-assisted in situ keratomileusis (LASIK) surgery.

Patient Preparation
There are no food or fluid restrictions unless by medical direction. Instruct the patient to withhold eye medications (particularly miotic eye drops which may constrict the pupil, preventing a clear view of the fundus, and mydriatic eyedrops in order to avoid instigation of an acute open-angle attack in patients with narrow-angle glaucoma) for at least 1 day prior to the test. Ensure that the patient understands that he or she must refrain from driving until the pupils return to normal (about 4 hr) after the test and has made arrangements to have someone else be responsible for transportation after the test.

Normal Findings

  • Normal visual acuity; 20/20 (with corrective lenses if appropriate).

Critical Findings and Potential Interventions

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