Dry eye is a condition that occurs when the eyes are not getting proper lubrication from through the tears. This can either be due to insufficient tear production, or poor quality of the tears produced. When a person blinks, a thin layer of tear film covers the eye to keep it moist and comfortable. The tear film comprises of 3 layers performing different functions. Meibomian glands produce the outermost layer, the oily layer, that keeps the tear surface smooth and reduces tear evaporation. The second watery layer is produced by lacrimal glands. Its purpose is to keep the eye clean and wash away any foreign material interrupting. The conjunctiva produces the third layer made up of mucus which helps the watery layer to evenly spread over the surface of the eye to keep the eye moist, otherwise the tears cannot remain stuck to the eyes.
Eye normally produces tears at a slow but steady rate to keep the eye moist and properly lubricated. In case a foreign particle enters or eye gets irritated, it suddenly starts producing an excessive amount of tears to wash out the foreign entity. A large amount of tears is also secreted when the eye gets dry or in response to some emotional situation (crying). Dry eye may occur due to any of the following reasons:
One condition is when lacrimal glands are not working proper enough to produce an adequate amount of watery fluid. As a result, the eye doesn't get proper lubrication and symptoms like irritation and inflammation in the eye may occur.
In some cases, the meibomian glands are not producing an oily secretion to reduce evaporation of tears. As a result, the eye secretes more watery fluid to keep the eye moist but it keeps flowing out of the eye or evaporates.
Symptoms like redness of eye, pain, irritation, itching, blurred vision, sensitivity to light and feeling of having some particle in the eye may appear in such situation. The problem may appear as a sign of natural aging process, such as menopause, or can be a side effect of some drugs.
The treatment of dry eye depends on the root cause of it. If it is a part of aging process then it can't be cured but can be treated by use of artificial tears or eye ointments. If the oil producing glands are blocked then a device called lipiflow is followed to unclog those glands. In case if the problem is with lacrimal glands, then an option is to plug drainage holes at the inner corners of eyelids from where the excessive amount of tears is drained into the nose. Eye surgery is not common, but there has been some instances when it was necessary to correct other visual problems.