discovering dry eye

The Controversy of Dry Eye Symptoms

BY KELLY KINNEY NICHOLS, OD, MS
November 1999

The word "symptom" is Greek in origin, and is used by clinicians to describe the subjective evidence of disease. Stedman's Medical Dictionary defines "symptom" as: "any morbid phenomenon or departure from the normal in structure, function or sensation, experienced by the patient and indicative of disease." If we were to extend this definition to dry eye, a symptom would be defined as: any complaint of ocular irritation experienced by patients who have the ocular disease dry eye.

What is a Dry Eye Symptom?

Dryness, grittiness, stinging, itchiness, foreign-body sensation, soreness and ache are some of the common terms patients use to describe their ocular irritation.

Some practitioners believe that in order to label a symptom as a "dry eye symptom," all other possible causes for the symptom must be ruled out, and the phrase "symptoms of ocular irritation" should be used in place of the phrase "dry eye symptoms." Other practitioners have a less stringent definition and believe that symptoms commonly expressed by patients with dry eye can be labeled "dry eye symptoms" without receiving a grammatical slap on the hand. Regardless of the level of literary etiquette, significant overlap exists between the symptoms for various ocular disorders that cannot be overlooked. It is beneficial to realize this overlap exists and to be able to sort out the symptoms and to match them with the correct condition.

Limited Vocabulary

Anterior segment disorders that mimic mild-to-moderate dry eye syndrome, such as blepharitis or ocular allergy, pose a universal problem in dry eye diagnosis since the symptoms are similar (if not the same) as those found in patients with dry eye syndrome. In addition, many clinicians associate specific symptoms with anterior segment disorders such as ocular itch and allergic conjunctivitis. Symptoms associated with common ocular disorders, as described in texts that cover the details of anterior segment disorders, can be seen in Table 1.

Not only are the symptoms similar in many anterior segment disorders, but objective signs are also similar. So how should we define dry eye? Should symptoms be used to define the ocular condition of dry eye? If so, are we creating a circular argument? Citing symptoms may seem reasonable, but it's not when they are easily confused with those of another disorder. So how do we interpret the cases we're treating? The controversy may be clear, but the solution is not. CLS

Dr. Nichols is a graduate student at The Ohio State University College of Optometry in the area of dry eye research.