By: Neil J. Friedman, M.D.
Dry Eye is one of the most common conditions that afflict our patients. The true incidence of dry eye has traditionally been underestimated, but it is believed to affect up to 35% of the population. In the past, dry eye was referred to as dry eye syndrome and keratoconjunctivitis sicca. Recently, ophthalmologists have gained a better understanding of the etiology and pathophysiology of dry eye. It is now defined as a disease (dry eye disease (DED)) with an underlying inflammatory component.
This chronic disease causes discomfort and visual disturbance, and it requires long-term therapy, often with multiple treatment modalities. DED also impairs patients’ quality of life. The burden of DED is directly associated with its severity. In fact, a study found the impact of severe DED on quality of life to be similar to that of class III/IV (moderate to severe) angina. Furthermore, DED can negatively influence outcomes of refractive and cataract surgery.
In 2007, a panel of leading external disease specialists issued a report on dry eye: the Report of the International Dry Eye WorkShop (DEWS). This comprehensive document is an important source for information regarding DED. One of the most helpful recommendations of the DEWS is the classification system it developed for staging and treating DED.
The cause of DED is multifactorial and varies from patient to patient. DED is associated with older age, female gender, hormone levels, environmental conditions (low humidity, circulating air, heat pollutants, irritants, allergens), and smoking. Other factors include eyelid and globe disorders (i.e., resulting in malposition, proptosis, or lagophthalmos), lacrimal gland abnormalities, corneal conditions (exposure keratopathy, neurotrophic keratopathy, contact lens wear, previous corneal surgery), other ocular surface disease (blepharitis, Meibomian gland dysfunction, allergic conjunctivitis, cicatrizing conjunctivitis), systemic disease (Sjogren’s syndrome, connective tissue disease, vitamin A deficiency), systemic medications (antihypertensives, antihistamines, antidepressants, retinoids), preservatives in topical medications, and reduced blink rate (reading and computer work, Parkinson’s disease).
When evaluating a patient with dry eye complaints, it is important to take a careful history and perform a thorough examination to document the symptoms and signs. Typical symptoms include burning, stinging, photophobia, redness, and tearing. Eye fatigue, particularly while reading or working on a computer, is common. It is critical to ask about factors that worsen or improve their symptoms. Questionnaires such as the Ocular Surface Disease Index (OSDI) or Impact of Dry Eye on Everyday Life (IDEEL) can be helpful as well. Symptoms are typically worse later in the day, although nocturnal lagophthalmos produces dryness most notable in the morning. Wind, altitude, and arid conditions exacerbate symptoms, and patients may find their vision fluctuates with blinking.
Signs that should be noted during the slit lamp exam include: conjunctival hyperemia, reduced height of the tear meniscus (Dry eye therapy must be directed toward the underlying cause(s). The mainstay of DED treatment is lubrication with artificial teardrops, gels, and ointments. Lacrisert, a slow release insert can also be quite effective by providing lubrication and stabilizing the tear film. Preservative free formulations are generally recommended if artificial tears are required more than four times a day. Restasis (cyclosporine ophthalmic emulsion 0.05%) has been shown to increase tear production and goblet cell density, and reduce reliance on artificial tears. A short course of topical steroids can be highly effective, but these agents are usually not recommended for long-term therapy due to their potential adverse effects. Oral supplements with omega-3 fatty acids (fish and flaxseed oils) can be beneficial as well. Punctal occlusion with plugs or cautery is also useful for aqueous deficient DED. Autologous serum drops are usually reserved for severe cases recalcitrant to other treatment modalities.
Finally, treatment of any other underlying systemic or ocular condition is necessary and may include avoidance of various exposures, behavior modification, change in medications, treatment of concomitant ocular surface disease, bandage contact lens, moisture chamber goggles, lid taping at bedtime, secretagogues, and surgery (i.e., repair of eyelid malposition, tarsorrhaphy, amniotic membrane transplant, and limbal stem cell transplantation). Treatment should be prescribed depending on the severity of disease and added in a stepwise fashion.
Education and compliance are vital to successful treatment. Patients must understand that dry eye is a chronic disease requiring long-term therapy. Treatment efficacy needs to be monitored closely. Traditionally, this has been based upon improvement in symptoms and signs. However, because DED has a significant impact on daily activities and quality of life, these measures should also be assessed when evaluating patient response to treatment.