Dry Eye Syndrome
What is dry eye?
Dry eye syndrome is a condition that occurs when your natural tears don’t adequately moisturize your eyes.
Dry eyes can manifest themselves with burning, tearing, redness, irritation, scratchiness, discharge, light sensitivity, foreign body sensation, and blurry vision.
Healthy tears are made up of 3 basic components:
1) Oil keeps the tears from evaporating too quickly.
2) Water with a bit of salt-keeps the eyes clean by washing away any foreign particulate matter such as dust, pollen, or mold.
3) Mucus-helps the tears spread evenly across the front surface of your eyes.
There are many causes of dry eye, but the two main causes are:
1) The body is just not producing enough tears. This is a medical condition called keratoconjunctivitis sicca.
2) The body is producing sufficient tears, but they are inadequate due to poor composition.
– If your tears don’t have enough oil, they cause dry eye by evaporating too quickly.
– If your tears don’t have enough water, the oil and mucus layers can mix causing a mucous-like discharge.
– If your tears don’t have enough mucus, dry spots can form because the tear don’t cover the front surface of the eye evenly.
Additional causes of dry eye can be eyelid abnormalities such as ectropion (aturning-out of the lids) and entropion (a turning-in of the lids)that make it difficult to blink or conditions such as bells palsy that prevent the lids from closing completely while blinking or sleeping.
Over exposure to very dry air or wind (ceiling fans) can cause dry eye by increasing the rate of evaporation of tears from the surface of the eye.
Aging and being postmenopausal are also a common cause of dry eye due to decreased tear production.
Prolonged fixation such as extensive reading or computer work, causes a significant decrease in the amount of times a person blinks their eyes per minute, resulting in a drying out of the surface of the eye.
Treatments for mild to moderate dry eye:
Over the counter lubricating drops or gels supplement your own tears and moisturize the eyes. These drops usually contain a preservative so they can only be used up to 4 times a day.
Prescription drops for dry eye, such as Restasis can help your eyes make more of their own natural tears while helping to replenish your tears lipid layer.
Punctum plugs are small collagen or silicone plugs which are placed in the nasal lacrimal duct that help keep your tears on the surface of your eye longer. These plugs must be replaced periodically once they dissolve or fall out.
Treatments for severe dry eye:
Low dose steroid eye drops control inflammation associated with dry eye.
Preservative free lubricating drops supplement your own tears and moisturize the eyes. They can be used several times a day since they don’t have preservatives, that can further dry the eyes.
Cauterizing the nasal lacrimal duct permanently closes the nasal lacrimal duct, thus keeping your tears on the surface of your eye longer.
Lubricating eye ointments are greasy ointments placed in the eye, usually at bedtime, that help keep the surface of your eye moist for extended periods of time.
Diseases associated with dry eye syndrome:
Allergic conjunctivitis is when allergens come in contact with the conjunctiva, and an allergic reaction, resulting in red, itchy, teary, and irritated eyes can occur. This disease often goes hand in hand with dry eye. If the tear film does not have enough water, or if tear production is inadequate, the allergens are not diluted and washed away, resulting in a concentration of allergens on the conjuctiva, and a worsening of allergic conjunctivitis symptoms. Treatments for allergic conjunctivitis include topical antihistamines, lubricating drops, topical NSAIDs, and in more severe cases a low dose topical steroid may be used to suppress inflammation.
Meibomian gland dysfunction involves the meibomian glands, located on the lid margins, that produce a lipid-like substance, which is essentially an oil. When these glands become clogged, the tear film is missing its outer layer of oil, thus the tears evaporate from the surface of the eye too quickly, resulting in dry eyes. Dry eyes caused by meibomian gland dysfunction must be treated differently than dry eye caused by deficient tear production. Supplemental lubrication is not sufficient. A steroid may be necessary for inflammation along with oral and topical antibiotics, as well as warm compresses, lid scrubs, and omega 3 supplements.
Auto immune diseases such as Sjogrens syndrome, rheumatoid arthritis, and collagen vacular disease, cause a deficiency in tear production, resulting in the development of chronic dry eye syndrome.