treatment plan

Dry Eye: Third of a three-part series on OSD

BY BRUCE E. ONOFREY, RPH, OD
JUNE 1998

Dry eye is not a simple condition. It is part of a broader classification of anterior segment disease known as ocular surface disease (OSD). Dry eye affects millions of people worldwide, with up to 38 million Americans at risk. It's one of the primary causes of contact lens failure and will become even more problematic as baby boomers reach middle age and beyond. Severe dry eye can lead to increased risk of bacterial keratitis and loss of sight. Typical symptoms include foreign body sensation and burning. Clinical signs include epiphora (reflex type), hyperemia, keratinization of the lid margins, punctate keratitis and conjunctival stippling. Causative factors are numerous and may include environment, systemic disease or medications (Table 1). A thorough medical, drug and social history is critical.

Tear Testing

Tear break-up time (TBUT) is the most common test for tear film stability and is also an indirect test of the mucin tear layer. Observing the corneal reflection stability with a keratometer is also an excellent way to evaluate tear quality and check K's, and it requires no fluorescein, which can stain a trial soft lens. Rose bengal is a direct measure of epithelial integrity and health, and its unique staining patterns are critical to the diagnosis of moderate to advanced dry eye disease. Schirmer's test, a quantitative measure of tear volume, can be performed quickly and easily with new color-changing material.

Dry Eye Therapy

Always aim to treat the underlying cause. This may require altering the patient's environment by increasing humidity or changing a medication that exacerbates dry eye. Urge patients to drink plenty of water and to avoid alcoholic beverages and salty foods which can worsen symptoms.

If you can't identify an underlying cause, aim to reduce symptoms. Artificial tears are the cornerstone of therapy, although patient compliance and preservative toxicity are problematic. Preservatives can produce epithelial damage and slow epithelial healing. Non-preserved, single-unit dose products avoid this problem but reduce compliance because patients find them inconvenient and wasteful. Fortunately, some artificial tears utilize "soft preservative" systems. CIBA Vision's Genteal employs a perborate/peroxide system which is neutralized within 20 seconds by tear enzymes. The preservative in Allergan's Refresh drops is neutralized by exposure to light.

Consider punctal occlusion when artificial tears are ineffective. A trial with collagen plugs will quickly indicate whether or not this is the proper treatment. You can choose between the intracanalicular or Herrick plug and the EagleVision/CIBA Vision surface-mounted system. The intracanalicular plug can be inserted quickly, easily and without discomfort, but it doesn't allow you to monitor its position. Complications of this type of plug can include canaliculitis and epiphora. Removal can be difficult at times. Due to their tapered design and premounted inserter, surface-mounted systems can be seen directly and removed easily. Patients who require complete punctal closure can undergo laser or thermal punctalplasty, but only after they've tried temporary and reversible punctal occlusion. CLS

[Editor's Note: Refer to "Detecting Dry Eye in Contact Lens Wearers" in this issue for more information about diagnosing dry eye.]

Dr. Onofrey, editor and author of various ophthalmic texts, practices in Albuquerque.