Dry eye
How is it diagnosed?
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| Fluorescein staining of the tears and cornea showing oily layer thinning and punctate epithelial erosions. |
The diagnosis of dry eye is made by assessing a patient's symptoms, looking for characteristic changes on the surface of the eye and performing a few simple tests.
Symptoms
The symptoms of dry eye vary depending on the severity.
Mild dry eye symptoms include:
- Grittiness
- Dryness
Severe dry eye symptoms include:
- Burning
- Fluctuating vision
- Sensitivity to light
- Pain
- Reduced vision
Examination
Patients with dry eyes usually have obvious changes in the tears and on the surface of the eye. These are assessed with the slit lamp microscope. The examination is aided by adding a small amount of an orange dye called fluorescein to the tears and then viewing with a blue light.
Common changes in dry eye include:
- A low volume tear 'prism' along the lower eyelid margin.
- Tiny 'pot-holes' called punctate epithelial erosions on the surface of the cornea, seen as bright blue dots.
- Thinning of the oily layer of the tear film which appears as expanding dark areas. The time these areas take to develop is known as the Tear Break Up Time. The break up time is reduced in patients with dry eye.
Schirmer's tear test
Schirmers' test
This is a simple test used to determine tear production. Small strips of a special paper are hooked over the lower eyelid. After 5 minutes the strips are examined. In very dry eyes the paper remains completely dry.
Blood tests
Some patients, particularly those with secretive dry eye or aqueous insufficiency, have inflammation in the lacrimal gland and elsewhere in the body. The most common example is patients who have rheumatoid arthritis. Blood tests can detect inflammation and the presence of such diseases. This helps both to confirm the diagnosis and plan treatment of the dry eye and other disease.