Dry eye syndrome is a condition resulting from an insufficient amount of moisture and lubrication on the surface of the eyes. Dry eye syndrome is one of the most common problems treated by eye physicians. Dry eye is becoming more and more common in today’s society as an estimated 16 million people have been diagnosed with dry eye in the United States. Symptoms can range from mild irritation to stinging, burning, and scratching sensations of the eyes. Dry eye can also result in fluctuating or poor vision, as well as contact lens intolerance.
The tear film is composed of 3 main layers: a lipid layer (oil), an aqueous layer (water), and a mucin layer (mucus). A malfunction in any one of the three layers can lead to dry eye and dry eye symptoms.
Lipid (Oil) Layer–This layer is the outer-most layer of the tear film and its purpose is to prevent the evaporation of the aqueous layer of the tear film as well as provide a smooth surface to the tears. The oils that make up this layer come from oil glands in our eyelids known as meibomian glands. If there is a deficiency in the layer the tears will evaporate too rapidly and dispose us to dry eye.
Aqueous (Water) Layer– This layer is the middle layer of the tear film and makes up the bulk of our tears. The purpose of this layer provide oxygen to the cornea from the atmosphere, act as an antibacterial barrier for the eye, and wash away debris. The aqueous layer comes from the lacrimal glands and a malfunction of the lacrimal glands will lead to a decrease in tear production and eventually dry eye.
Mucin (Mucus) Layer– This is the inner-most layer of the tear film and its primary purpose is to help the tears stick to the surface of the eyes. This layer is made from the conjunctiva, a clear tissue overlying the white part of the eye. If there is a deficiency in this layer tears will not stick to the eye as well, again leading to dry eye.
Risk factors that can lead to a deficiency in one or more layers of the tear film are:
Gender (Dry eye is more common in females than males)
Autoimmune conditions such as Sjogren’s syndrome, thyroid disorders, lupus, and rheumatoid arthritis
Medications including diuretics, antiallergy medications and decongestants, antidepressants, antipsychotics, acne medications, and birth control
Diet (vitamin A deficiency)
Laser eye surgery
Long-term contact lens wear
Wind, smoke, and other environmental factors including computer and mobile device use
Eyelid injury or surgery
Types of Dry Eye
Evaporative Dry Eye
Evaporative dry eye occurs when the tears evaporate from the surface of the eye too rapidly. Oil made from eyelid glands (meibomian glands) is improperly or insufficiently produced leading to rapid evaporation of the existing tears on the eyes.
Aqueous Deficient Dry Eye
Aqueous deficient dry eye occurs simply due to an insufficient amount of tears being produced to properly hydrate the ocular surface. There are two distinctions of aqueous deficient dry eye: Sjogren and Non-Sjogren.
Sjogren Syndrome Dry Eye: This type of dry eye occurs secondary to an autoimmune condition known as Sjogren syndrome in which the body’s own immune system attacks the lacrimal gland causing a reduction in the amount of tears produced. It is almost always associated with dry mouth or xerostomia.
Non-Sjogren Dry Eye: This type of dry eye occurs when the lacrimal gland is not producing enough tears for any reason excluding Sjogren syndrome; the most common being age-related dry eye.
Dry eye is a chronic disease and therefor requires chronic treatment. Luckily there have been many advancements made in recent years for treating and managing signs and symptoms of dry eye. The treatment that works for one person may not work for another depending on the type of dry eye occurring. Current treatments include:
Artificial tears/lubricants: Available without prescription, artificial tears work well for mild to moderate cases of dry eye and range from a liquid formulation for mild cases, to gels and ointments for more moderate and severe cases.
Hot compresses: Hot compresses help in evaporative cases of dry eye by melting solidified oils that block and prevent the formation of the lipid or oil layer of our tear film.
Tear care: This is an in-office procedure for moderate to severe cases of evaporative dry eye. It clears blocked meibomian glands and lasts anywhere from 6-18 months.
Eyelid hygiene: Foams, sprays, and towelettes specifically formulated for the eyelids help to reduce eye inflammation, which helps to reduce dry eye symptoms and maintain the lipid or oil layer of our tear film.
Hydroeyes: These supplements contain a blend of omega fatty acids, antioxidants, and other nutrients to improve and maintain the quality of all layers of the tear film and reduce signs and symptoms of dry eye.
Punctal plugs: Ours tears drain into our tear ducts through an opening in our eyelids. A punctal plug is used to block these drains and helps to keep more tears on the surface of our eyes.
Restasis, Xiidra, Cequa: These prescription medications help reduce the inflammation associated with dry eye, which in turn helps the eyes produce more natural tears.
Vital tears: These are a form of tears derived from your blood serum. Often very effective in treating dry eye signs and symptoms that have not responded to more conservative treatment.
Specialty contact lenses: Certain types of contact lenses (scleral lenses) cover the eye and protect it from the environment and help keep it hydrated throughout the entire day. Also shown to be effective in treating dry eye signs and symptoms that have not responded to more conservative treatment.