Refraction

Exam for Eyeglasses

The refraction part of your eye exam refers to that segment where you are tested for glasses. The term “refract” means to bend. The refraction involves using lenses to bend light in order to cause the image (object at which you are looking) to fall on your retina. You are probably familiar with sitting behind the large device that contains rotating lenses. The practitioner shows you various lenses, asking which is better. Your answers, in part, determine your glasses prescription.

But there’s more to it than that. First, the examiner needs a logical place to start. This may be based on your vision (see Vision Test), on the prescription of your present glasses, on a computer test, or on a special test called retinoscopy. During retinoscopy, the examiner evaluates the way in which light is reflected from your eye. Lenses are used to adjust this reflection until any nearsightedness, farsightedness, and/or astigmatism is corrected. This test is especially valuable for children or others who cannot communicate well enough to give input when the lenses are changed.

Once a starting point has been found, the examiner asks your opinion on how things look. Are the letters more clear with Glass #`1? Or with #2? This process is sometimes a little confusing. Try to relax, and don’t be afraid of giving a “wrong” answer. If you truly are inconsistent, the examiner uses a system of rechecks to help find the best lens for you.

Jan Ledford, COMT
EyeWrite Productions