Dry Eye - Evaluation & Work up

Dry eyes can usually be diagnosed by the symptoms alone.Tests can determine both the quantity and the quality of the tears.

A slit lamp examination can be performed to diagnose dry eyes and to document any damage to the eye.

Dry eyes can usually be diagnosed by the symptoms alone.Tests can determine both the quantity and the quality of the tears.

A slit lamp examination can be performed to diagnose dry eyes and to document any damage to the eye

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Diagnosis of Dry Eye

Dry eyes can usually be diagnosed by the symptoms alone.Tests can determine both the quantity and the quality of the tears.A slit lamp examination can be performed to diagnose dry eyes and to document any damage to the eye.
A Schirmers test can measure the amount of moisture bathing the eye. This test is useful for determining the severity of the condition. A five-minute Schirmer's test with and without anesthesia using a Whatman #41 filter paper 5 mm wide by 35 mm long is performed.For this test, wetting under 5 mm with or without anesthesia is considered diagnostic for dry eyes.
If the results for the Schirmers test are abnormal, a Schirmer II test can be performed to measure reflex secretion. In this test, the nasal mucosa is irritated with a cotton-tipped applicator, after which tear production is measured with a Whatman #41 filter paper.For this test, wetting under 15 mm after five minutes is considered abnormal.
A tear breakup time (TBUT) test measures the time it takes for tears to break up in the eye.The tear breakup time can be determined after placing a drop of fluorescein in the cul-de-sac.
A tear protein analysis test measures the lysozyme contained within tears.In tears, lysozyme accounts for approximately 20 to 40 percent of total protein content.
A lactoferrin analysis test provides good correlation with other tests.
The presence of the recently described molecule Ap4A, naturally occurring in tears, is abnormally high in different states of ocular dryness. This molecule can be quantified biochemically simply by taking a tear sample with a plain Schirmer test. Utilizing this technique it is possible to determine the concentrations of Ap4A in the tears of patients and in such way diagnose objectively if the samples are indicative of dry eye.

Anatomy of the Tear Film

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Mucin Tear Deficiency

might be due to decreased Vitamin A, alkali burns, Cicatricial pemphigoid, SJS
increased tear break-up time

Lipid Tear Deficiency

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Dry Eye Tests

Tests for evaluation of dryness

basic secretion test
Schirmer I
Schirmer I
Tear meniscus
Tear breakup time

As part of our eyes' normal function, tear film is produced, spread over the eyeball, and continually washed out through tiny holes on the edges of the upper and lower eyelids. Our impulse to blink is due to the tear film thinning out and evaporating, giving us the automatic impulse to blink and refresh the tear film. The process of the tear film thinning out is called tear film break-up.
When not enough tear film is being produced to keep the eye moist between blinks, or when the tear film composition is abnormal, tear film break-up can occur too quickly—before our impulse to blink. This causes dry spots to appear on the eye's surface (cornea).

Even if tear film is fairly normal, dry spots can still appear if the cornea has been compromised in some way. The cells on the corneal surface have very delicate structures that allow the tear film to stick to the eye, and if compromised, tear film can break-up too quickly