Refraction

Refraction is a phenomenon of physics that occurs when a light wave passes through a material at an angle and is bent at a different angle as it travels from one medium to another. This bending of the light wave, or refraction, helps us view objects both close and far.

Preparation for Refraction Test

Before having a refraction test done, the patient should make sure their eyes are healthy and their eyeglasses prescription is current. They may also need to have their pupils dilated to get an accurate result.

Procedure of Refraction Test

To perform a refraction test, the eye doctor will ask the patient to look into an instrument called a phoropter. The phoropter contains a series of lenses which the eye doctor will adjust until the patient can see clearly. The patient will be asked which of two lenses appears clearer. After the test is complete, the doctor will prescribe a set of glasses with the correct lenses for the patient's vision.

Types of Refraction Tests

Auto refraction
Keratometry
Non-cycloplegic refraction
Random-dot stereopsis
Retinoscopy

Risks of Refraction Test

In general, a refraction test is a simple procedure that usually has minimal to no risk. However, the dilation of the pupils may cause sensitivity to light, temporary vision changes, or blurred vision for several hours, depending on the drops used.

Why & When to get a Refraction Test

A refraction test is usually done when a person has difficulty seeing clearly, • whether or not they already wear glasses or contact lenses. It can be used to diagnose nearsightedness, farsightedness, astigmatism, and presbyopia. It should be done annually, or as often as your eye doctor recommends.