It is a disease in which the tear production is reduced or the tear film stability over the cornea is reduced.
There is not a simple cause of the dry eye, since multiple factors may favor this disease. It is quite common to find milder forms known as sub clinical dry eye, cases where dryness criteria are found on examination but the patient does not refer symptoms. In these cases, lachrymal stability is borderline and only one additional factor may trigger. Air conditioner, contact lenses, or any other factors can trigger symptoms of dryness.
The most common symptoms are: dryness sensation, burning sensation, difficulties in winking, and ocular tiredness. In more severe cases, blurred vision and sharp pain may also appear. In more severe complications (as in the ulcer), the disease can also cause pain and other symptoms.