Eye Examination Procedures

A comprehensive eye exam studies the interior and exterior of both eyes through a battery of tests. These tests not only determine your prescription strength; they are also helpful in diagnosing conditions such as macular degeneration and glaucoma. Eye exams are especially important for people wearing glasses or contacts, as they may experience changes in their vision.

Glaucoma Test

• During a glaucoma test, a puff of air is blown in the patient's eyes. This puff of air measures fluid buildup in the eyes, a symptom of glaucoma that decreases vision and eventually causes blindness.

Visual Accuracy Test

• A visual accuracy test takes place using an eye chart containing rows of letters. The letters start out large, then get increasingly smaller as the patient reads down the chart. The eye doctor will ask patients to read specific rows of letters on the eye chart, testing their vision at various distances.

Shadow Test

• A shadow test, or retinoscopy, is necessary to determine a person's estimated prescription strength. The eye doctor dims the lights and instructs the patient to stare at a designated area of the room. He then places a machine with different lens strengths in front of the patient's eyes, flipping them while simultaneously shining a light in both eyes. A person's estimated prescription strength is determined by how well her eyes reflect the light through the lenses.

Refractive Error Test

• The refractive error test gives an accurate depiction of a person's prescription strength to determine if she has visual problems such as farsightedness, nearsightedness and astigmatism. Similar to a shadow test, the eye doctor places different lens strengths in front of the patient's eyes and flips them. During the procedure, he instructs the patient to read letters on an eye chart using the lenses, asking her which ones promote better eyesight. Through this inquiry, the eye doctor can pinpoint whether a patient may need glasses or contacts.