Patient Education

What is dry eye syndrome and how is it treated?

Dry eyes can result either from decreased tear production or too much evaporation of the tears from blepharitis or exposure. Blepharitis is inflammation of the eyelids, where the oily coating of the tears is produced. Exposure occurs when the eyes do not close properly.

The tear film is composed of three main layers, like a sandwich. The outer layer, called the lipid or oily layer, is produced by the meibomian glands in the eyelids. The middle layer, the aqueous layer, is produced by the tear (lacrimal) glands. The inner layer, the mucin layer, is produced by cells in the conjunctiva. If anything is wrong with any layer of the sandwich, patients can have symptoms of dry eye.

Decreased tear production, known as aqueous tear deficiency, has the technical name of keratoconjunctivitis sicca. There are many reasons for this problem including aging and certain medications, but often the cause is unknown. Sjogren’s syndrome – dry eye and dry mouth – can be either primary (no known systemic disease) or secondary – related to a connective tissue disorder, such as rheumatoid arthritis.

Decreased tear production can result in burning, stinging, itching, foreign body sensation, dryness, soreness, heaviness of the lids, light sensitivity and/or ocular fatigue. Occasionally there may be episodes of excessive tearing due to dryness causing severe irritation of the eyes. Symptoms often are worse at the end of the day and can be aggravated by certain activities (e.g. reading, watching television, working on the computer) and certain environments (e.g. airplane cabins, air conditioners, smoky rooms.)

Evaluation of dry eyes includes several tests done in the office. Fluorescein dye (yellow drops placed in the eye) marks areas where the tear film isn’t healthy. It can detect microscopic corneal scratches and areas where the tear film isn’t covering the cornea well (tear break-up time). Rose-Bengal dye (red drops placed in the eye) staining, which is more sensitive in early or mild cases and picks up less severe dry eyes, may also be used. Schirmer testing involves placing small filter paper strips in the eyes to measure tear production. Less than 10 mm of tears is abnormal. Most of these tests are done as a part of a complete evaluation for dry eyes.

Treatment for dry eyes starts with the most minimally invasive steps, such as lubrication (drops, gels and ointments). If lubricants are being used more than four times per day, preservative-free preparations are recommended. Gels and ointments may blur vision. Most patients prefer to use them later in the evening when they don’t have high visual needs. A new eye drop, cyclosporine 0.05% (Restasis), has been shown to stimulate tear production. It is useful for patients whose dry eyes have an inflammatory component and some capacity to make tears. It causes temporary burning in about one-fifth of the users and may take several weeks to have an effect. Closure of the tear drainage ducts (punctal occlusion) can be helpful in some patients as it blocks the exit of tears from the eye, ideally keeping it more lubricated. Punctal occlusion can be done with a plug or cautery and may be beneficial when adequate relief is not obtained from other treatments.

Blepharitis, or eyelid inflammation, can give similar symptoms to aqueous tear deficiency as it affects production of the eyelid oils, which coat the tears. The outer oily layer of the tear film slows down the evaporation of tears from the eyes. Loss of this layer can lead to increased evaporation of tears and dry eyes. Treating blepharitis involves warm compresses that, when applied for five to ten minutes, make the thickened oily component of tears more liquid. If there is significant crusting of the eyelashes, lid scrubs with diluted baby shampoo may decrease some of the inflammation. Lid massage, topical antibiotic ointments such as bacitracin or erythromycin and oral antibiotics (tetracycline family or erythromycin) also may help treat blepharitis. In some circumstances, topical steroids are used to decrease the eyelid inflammation. Their use, however, should be minimized. Patients using topical steroids need careful follow-up, as they could lead to cataracts and glaucoma. A physician needs to monitor these medications and check intraocular pressure regularly.

As with all eye conditions, patients with symptoms of dry eye should have a careful and complete eye examination before any treatments are started.