What is Dry Eye ?

Dry eye occurs when the eye is no longer making as many tears properly, or not the same quality of tears as it used to do .

Dry eye is very common.in fact , among women over the age of 50 and what this is  a  feeling  of  irritation , burning , a sandy sensation as  if   there  is  something  in  the eye.

If left untreated, dry eye can lead to pain, ulcers,or scars on the cornea, and some loss of vision. However, permanent loss of vision from dry eye is uncommon.it’s called also keratoconjunctivitis sicca, dysfunctional tear syndrome. 

Types of dry eye :

1-Aqueous tear-deficient dry eye is a disorder in which the lacrimal glands fail to produce enough of the watery component of tears to maintain a healthy eye surface. 

2-Evaporative dry eye may result from inflammation of the meibomian glands, also located in the eyelids. These glands make the lipid or oily part of tears that slows evaporation and keeps the tears stable. 

Dry eye can associated with :

**inflammation of the surface of the eye. 

**any disease process that alters the component of the tears. 

**an increase in the surface of the eye, as in thyroid disease when the  eye  protrudes  forward. 

**cosmetic surgery, if the eyelids are opened too widely.