Dry eyes occur when tears are not produced in sufficiently (poor quantity), or when they evaporate very quickly because of alteration in the constituents (poor quality). In addition, inflammation of the ocular surface can produce a dry eye.
What causes Dry eye?
Poor quality of tears-
Due to imbalance in the components of tears i.e.-oily layer, mucus layer and aqueous layer.
The oily layer is the outermost layer and prevents the evaporation of the aqueous layer. The oily layer is produced by the meibomian glands which are on the edge of the lid margin. Any condition which causes inflammation of the lid margin (blepharitis) or the meibomian glands (meibomitis) leads to the production of an unstable oily layer which breaks up fast and leads to evaporation of the tear film.
The aqueous layer is produced by the lacrimal (tear) glands. It contains water and electrolytes. If this layer is absent or inadequate it leads to contact between the lipid (oily) layer and the mucus layer producing discharge.
The mucus layer helps to evenly spread the tear film over the ocular surface. Lack of mucus cause dry spots on the corneal surface.
Poor quantity of tears-
It is also called as keratoconjunctivitis sicca.
It is caused by a primary decrease in tear production from the tear glands either due to damage to them secondary to some disease or damage to the glands. However the commonest cause is aging as the production decreases with age above 45-50 years and in post menopausal women due to hormonal imbalance.
Certain systemic diseases such as Sjogrens syndrome, Rheumatoid arthritis, Systemic sclerosis, Thyroid diseases, Vitamin A deficiency, skin diseases, also cause dry eye.
Some Common medicines that can cause dry eye are antihistamines, O.C pills, anti depressants, diuretics, antimuscarinics and some blood pressure medications.
Temporary causes of dry eye are: continuous work on computers, T.V. , Books and even dry and windy climates can cause dry eye. Any surgical procedure on the eyes can also lead to temporary dry eyes. Also prolonged contact lens wear
They cause dry eye due to unequal distribution of the tear film over the ocular surface.
What is the treatment of dry eye?
There is no permanent cure for primary dry eye., however the treatment is aimed at alleviating the symptoms and relieving discomfort.
The main goals of treatment are:
Replenishing the eyes moisture using artificial tears, gels and ointments.
Delaying the drainage of normal tears by blocking the normal drainage of tears so that they remain longer on the surface of the eye.
Preventing further damage to the cornea.
What are the symptoms of dry eye?
Burning sensation in the eyes
Gritty or sand particle sensation in the eyes.
Foreign body sensation in the eye.
Itching and stinging in the eyes.
Redness, typically in the exposed conjunctiva between the two lids.
Light sensitivity (photophobia).
Intermittent blurring of vision that improves with blinking.
Watering of eyes. (This is because the dryness causes irritation which results in reflex tears.)
Decreased tolerance to contact lenses.
Discomfort on reading watching T.V.etc.
If left untreated will dry eyes harm my vision?
No, vision will not be harmed .However it can lead to damage to the tissues on the ocular surface and cornea leading to vision impairment. It can lead to worsening of contact lens intolerability and discomfort. This can also greatly increase the chances of infection.
How can I help n the management of my dry eye?
Use lubricating eye drops.
Avoid being in a dry atmosphere for long periods of time.
Avoid the direct blast of the A.Cs, on the face especially while driving.
Drink plenty of water; about 8-10 glasses in a day.