What Is Eye Refraction

A refraction is an eye test performed during a comprehensive eye exam that measures a patient’s prescription for eyeglasses or contacts. During the refraction test, the patient will sit in a chair looking through a special device called a phoroptor or refractor and focus on an eye chart 20 feet away.

What causes refraction in the eye?

Most refraction in the eye occurs when light rays travel through the curved, clear front surface of the eye (cornea). The eye’s natural lens also bends light rays. Even the tear film on the surface of the eye and the fluids inside the eye (aqueous humor and vitreous) have some degree of refractive ability.

What does a Phoropter do?

A phoropter is an instrument used to test individual lenses on each eye during an exam. If, during an eye examination, your doctor has discovered a vision problem like nearsightedness, farsightedness or astigmatism, it’s likely that one of the next steps you’ll take will involve a phoropter.

James H. Sterling

James H. Sterling

Environmental Science & Climate Journalist

James Sterling reports on renewable energy developments, climate policy, ecological conservation, and green tech innovations around the globe.

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