The human eye constantly produces tears to keep the eye moist and lubricated. Dry eyes is a condition caused by a lack of tears and usually results in, itching, burning, blurred vision, thick discharge and heavy eyelids. The causes of dry eyes can range from age, vitamin A deficiency, the result of a drug interaction to weather. Women who have gone through menopause are especially susceptible to dry eyes. Dry eyes can result in diminished vision, so it is very important to get tested.

The Schirmer Test

The Schirmer test is the most common test for dry eyes. During this test, a piece of filter paper is placed over the conjunctival sac of the eye for up to five minutes. The filter paper will absorb the tears in the eye. If the filter paper absorbs less tears than what should normally be expected, subsequent Schirmer tests may be given to verify the initial finding and to make a positive diagnosis.

The Phenol Red Thread Test

The phenol red thread test is another commonly used test to detect dry eyes. A cotton thread containing phenol red dye is placed in the lower conjunctival fornix. The thread actually has a yellow color but will change to red when it comes into contact with tears. Once the thread is removed, the section of the thread that has been wet by tears is measured in millimeters. A normal measurement will be between 9 and 20 millimeters. A person with dry eyes will have less than 9 millimeters.

The Fluorescein Breakup Time Test

If they eye does not produce tears continuously and stops intermittently, the fluorescein breakup time test can detect how long eyes stop producing tears. In this test, a strip of fluorescein is is applied to the lower eyelid fornix and then removed after 15 seconds. The patient then blinks three times and the eye is examined under a cobalt-blue filtered light. This light will detect the first appearance of tears to appear on the surface of the eye.

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Dry Eyes

Dry Eye Tests and Exam