dry eye
Managing Dry Eye in Your Pediatric Patients
While not common in younger individuals, dry eye does occur. Learn how to spot it and treat it effectively for this patient population.
BY SRIHARI NARAYANAN, B.OPTOM., M.S., Houston, Texas

The National Eye Institute/Industry Workshop (1998) defined dry eye as a disease that arises either because of decreased tear production or increased evaporation of tears that results in symptoms of ocular irritation. Recent estimates indicate that 10% to 30% of the adult population suffers from dry eye disease, with the prevalence increasing in older populations.

Dry eye disease occurs relatively rarely in children and practitioners frequently misdiagnose the condition in this patient population. If you suspect dry eye in a juvenile patient, perform thorough subjective and objective evaluations to confirm the diagnosis and manage the condition. (See "Dry Eye in a Pediatric Patient" on page 76 for a suggested method of treating these patients.)

The subjective assessment

Obtaining a good patient history will provide useful clues for the diagnosis of dry eye. Though a child suffering from dry eye may not complain of dryness, the child will probably describe the presence of other ocular irritation symptoms such as burning, scratchiness, itching and, rarely, photophobia. Parents may have noted an irritable and/or moderately red eye and that the child's symptoms change with different environmental conditions.

For example, symptoms may worsen during a vacation in a place with dry weather or during an airplane trip. Question parents whether the child sleeps with his eyes partially open at night. Also inquire about the presence of diseases involving the joints, skin, guts and respiratory system. Note the child's current systemic or topical medication schedule (if any). Finally, note any form of radiation therapy or chemotherapy, as these can damage many of the glands involved in tear secretion.

The objective assessment

The diagnosis of dry eye usually necessitates a battery of tests. Considering that the patient is a child, you should first implement the least invasive tests in the shortest possible time and then progress to other tests. You can easily obtain useful information from external inspection and from a basic biomicroscopic exam. Here's an idea of how to proceed:

External inspection. Assess blink rates and determine whether the blink completely covers the ocular surface. Examine the child for lid/orbital abnormalities, skin lesions and scars.

Slit lamp biomicroscopy. Check for the presence of blepharitis, meibomitis, tear film debris, mucus filaments, superficial punctuate keratitis, assess the tear meniscus, tear break-up time (TBUT; older children), fluorescein and lissamine green staining. You can assess TBUT noninvasively in a variety of ways including the use of keratometer mires.

Schirmer test. Try this method with older children using an anesthetic or with younger children during sleep. Most children will wet 15 mm or more in five minutes. A value less than 5 mm is definitely a cause for concern. You can try the phenol red thread test (cotton thread) as an alternative to Schirmer's test because the thread doesn't irritate the eye.

Other objective tests. Some authors suggest performing impression cytology in older children. You can measure tear osmolarity, considered to be the "gold standard" for dry eye diagnosis. An osmolarity greater than 312 mOsm/Kg is considered diagnostic of dry eye. This test requires a greater amount of patient cooperation during the collection of the tear sample and easy access to an osmometer.

The watering eye. Keep in mind that a dry eye patient may present with a "watering eye" (epiphora). It's important to rule out common causes of epiphora in children such as nasolacrimal duct obstruction, subtarsal or corneal foreign bodies, conjunctivitis, glaucoma, crocodile tears and contact lens-associated epiphora.

Your subjective and objective assessments will provide you with valuable information, which is beneficial because a number of conditions can affect one or more layers of the tear film and can cause dry eye in children.

Why some kids are dry

Below are some common causes of pediatric dry eye:

Mucin deficiency. Goblet cells are the primary producers of tear mucin, though recent research has shown that the ocular surface epithelial cells secrete certain types of mucins. Deficiency of tear mucin destabilizes the tear film. Stevens-Johnson syndrome, burns and pemphigoid (in older children) are the common causes of mucin deficiency. In the developing world, vitamin A deficiency (xerophthalmia) and trachoma are the most important conditions that affect the mucin layer of the tear film.

Lipid deficiency. The meibomian glands (tarsal glands) are the main contributors to the anterior oily layer of the tear film. A decrease in tear lipid layer promotes a faster evaporation of the tear film. The most common causes of tear lipid deficiency include blepharitis and meibomitis. Radiation therapy can cause meibomian gland dropout, leading to a serious deficiency in the tear lipid layer.

Aqueous tear deficiency. The aqueous layer of the tear film lies in between the lipid and mucin layers and forms the bulk of the tear film. Recent research suggests that the aqueous layer also dissolves tear mucins, making it more of a gel-like layer. The main lacrimal gland produces the majority of the aqueous layer.

Classic aqueous tear deficiency (ATD), also known as keratoconjunctivitis sicca, is a disease of the middle age. Sjögren's syndrome occurs when ATD is associated with systemic autoimmune disease. We rarely see this disease in children, but when we do, we may associate it with polyarteritis nodosa, Wegener's granulomatosis, acquired immunodeficiency syndrome (AIDS) and also following bone marrow transplantation. A localized drying of the exposed palpebral surface can occur because of lagophthalmos, proptosis or facial palsy and even following ocular surgeries such as those for strabismus.

Some of the other causes of ATD in children include congenital alacrima (or hypolacrima), corneal hypesthesia associated with decreased reflex tearing, familial glucocorticoid deficiency (Allgrove syndrome), ectopic lacrimal gland development, lacrimal fistulas, lacrimal tissue with dermoid cysts, cranio-facial malformations and familial dysautonomia (Riley-Day syndrome).

Treating the pediatric patient

You can treat dry eye in case of drug-induced dry eye or vitamin A deficiency. Manage blepharitis and meibomitis by teaching the child's parents to massage the child's lids and to clean the lid margins using diluted baby shampoo (one teaspoon of shampoo in one cup of lukewarm water) twice a day. Application of an antibiotic/corticosteroid combination ointment to the lid margin (in small quantities) can help in the early stages of treating blepharitis.

Reduction or loss of tears. Prevent tear loss by avoiding dry climates, humidifying living and sleeping areas, vacationing in humid locations and considering punctual occlusion, if necessary.

Artificial tears. Preservative-free artificial tears/rewetting agents are the most frequently used treatment for dry eye conditions. Though a number of artificial tear formulations are available, doctors usually prefer a certain type of rewetting agent.

Other treatment paradigms: Consider advising tarsorrhaphy in case of severe dry eyes, especially when associated with corneal hypesthesia. You can also try lid padding/taping when the cornea is exposed, though this requires careful control. Treat excess mucus production with 10% acetylcysteine drops q.i.d. Eyecare professionals have successfully used topical cyclosporin A in children who have Sjögren's syndrome (experts don't recommend using cyclosporin A in pediatric patients).

Make a difference

Pediatric patients who have dry eye disease require your careful investigation into the cause of their condition for appropriate management. So ask the right questions, perform the right tests and you can really improve these patients' lives. Just ask their parents.

References or further reading are available by e-mailing your request to the author.

Srihari Narayanan has a Master's degree in dry eye research from the University of Houston and is currently pursuing a Ph.D. and O.D. there. His research is now focused on the inflammatory component in dry eye disease. He is a current William C. Ezell Fellow of the American Optometric Foundation. E-mail him at nsrihari@uh.edu.