Brief Description, Types, Sign and Symptoms, Causes And Treatment Of Dry Eye Syndrome

Dry eye occurs due to improper or insufficient production of tears to lubricate and nourish the eyes.  In addition, inflammatory reactions of the eye surface may occur along with dry eye. 
Although permanent loss of vision from dry eye is uncommon, if left untreated it can lead to pain, ulcers, or scars on the cornea, and some loss of vision.

 Dry eye is also referred to as dry eye syndrome, dysfunctional tear syndrome, keratoconjunctivitis sicca (KCS), evaporative tear deficiency, aqueous tear deficiency, lacrimal keratoconjunctivitis, and LASIK-induced neurotrophic epitheliopathy (LNE). Although dry eye can occur at any age, it is most common and frequent in elderly people. Dry eye is more common after women after menopause. Women who experience menopause prematurely are more likely to have eye surface damage from dry eye.

Dry eye syndrome patients find it more difficult to perform some certain activities, such as reading or using a computer for an extended period of time, and it has been found to decrease tolerance for dry environments.

Dry eye can either be aqueous tear-deficient dry eye or evaporative dry eye.
Aqueous tear-deficient dry eye occurs when the lacrimal glands fail to produce enough of the watery component of tears to maintain a healthy eye surface. This may be due to damage to the gland or deficiency of vitamin A.
On the other hand, evaporative dry eye occurs when the oily part of tears that slows down evaporation and keeps the tears stable is deficient. This may be due to inflammation of the meibomian glands that produces the oily part of tears.

Causes of dry eye

• Dry eye may be a side effect of some certain medications, including anti-depressants, tranquilizers, antihistamines, birth control pills, nasal decongestants, Parkinson’s medications, certain blood pressure medicines, hormone replacement therapy and certain acne treatment.
•  Diseases of eyelid skin and its glands such as meibomian gland dysfunction can result in dry eye.
• Pregnant women and women under hormone replacement therapy may experience dry eye symptoms. Women taking only estrogen have a 70 percent increased risk of developing dry eye whereas those taking estrogen and progesterone are 30 percent more likely to experience dry eye. 
• Dry eye can also develop after performing a special type of refractive surgery known as LASIK. The dry eye symptoms experienced after LASIK surgery generally last for three to six months, but may last longer in few cases. 
• Chemical and thermal burns that damage the membrane lining the eyelids and covering the eye can also result to dry eye. 
• Prolonged use of computer or staring at video screens, may also lead to dry eye symptoms due to infrequent blinking associated with the use of such devices. 
• Both insufficient and excessive dosages of certain vitamins especially vitamin A can contribute to dry eye.
• Loss of corneal sensation from long-term wear of contact lens can lead to dry eye. 
• Dry eye can also be associated with immune system disorders such as rheumatoid arthritis, lupus and Sjögren’s syndrome. Other medical conditions associated with dry eye include allergies, diabetes, infections and thyroid disorder. 
• Dry eye can be a symptom of chronic inflammation of the conjunctiva or the lacrimal gland which may be caused by certain eye diseases, infection and exposure to irritants such as tobacco smoke, chemical fumes or drafts from air conditioning or heating. 
• Exposure keratitis that occurs when the eyelids do not close completely during sleep may also lead to dry eye.

Signs and Symptoms

Dry eye symptoms may include any of the following:

•  Burning or stinging sensation of the eye;
• Gritty or sandy feeling as if something is in the eye; 
• Episodes of excess tears following very dry eye periods; 
• A stringy discharge from the eye; 
• Pain and redness of the eye; 
• Episodes of blurred vision; 
• Heavy eyelids; 
• Inability to cry when emotionally stressed; 
• Uncomfortable contact lenses; 
• Decreased tolerance of reading, working on the computer, or any activity that requires sustained visual attention; 
• Eye fatigue.

NOTE: If symptoms of dry eye persist, consult an eye care professional to get an accurate diagnosis of the condition and begin treatment to avoid permanent damage.

Treatment

Depending on the causes of dry eye, the eye doctor may use various approaches to relieve the symptoms.
The first priority in dry eye treatment is to determine if a disease is the underlying cause (such as Sjögren’s syndrome or lacrimal and meibomian gland dysfunction). If it is, then the underlying disease needs to be properly treated.

Topical cyclosporine (Restasis) is an anti-inflammatory medication and is the only prescription drug available to treat dry eye. It reduces corneal surface damage, increases tear production, and decreases symptoms of dry eye. It usually takes three to six months of twice-a-day dosages for the medication to work. In some severe cases, short term use of corticosteroid eye drops that decrease cell-mediated inflammation is required.

If dry eye is caused by a medication, the eye doctor should switch to a medication that does not cause the dry eye side effect.

If the cause of dry eye is contact lens wear, then the eye care practitioner should recommend another type of lens or reduce the number of hours the patient wears the contact lens. In severe cases, the eye care professional may advise the patient not to wear contact lenses at all.

Another option is to plug (also known as lacrimal plugs or punctal plugs) the tear drainage holes.  The plugs (made of silicone or collagen) can be inserted painlessly by an eye doctor into the small circular openings where tears drain from the eye into the nose. This option is temporary and reversible but in severe cases, permanent plugs may be considered.

In some cases, a simple surgery (punctal cautery) is performed to permanently close the tear drainage holes. This surgical procedure helps to keep the limited volume of tears on the eye for a longer period of time.

Supplements rich in omega-3 fatty acids or dietary sources (such as tuna fish) of omega-3 fatty acids may decrease symptoms of dry eye. The use and dosage of these supplements and vitamins should be discussed with the primary medical doctor.

Use of tear substitutes such as artificial tears, gels, gel inserts, and ointments offer temporary relief and provide an important replacement of naturally produced tears in patients with aqueous tear deficiency. However, application of artificial tears with preservatives more than four times a day or preparations with chemicals that constrict blood vessels should be avoided.

The patient should allow his eyes to rest when performing activities that requires him to use his eyes for long periods of time and should instill lubricating eye drops while performing these tasks. In addition, avoidance of dry conditions and wearing of wrap around shades can help slow down tear evaporation from the eye surfaces.