Dry eyes occur due to a disturbance of the constantly necessary moisture on the surface of the eye. This leads to numerous complaints.
In order to stay healthy, the eye has to be kept moist - always and everywhere - even on the ocular surface and with the lids open for vision. This is done through the thin tear film on the eye.
If the tear film is disturbed, the sensitive mucous membrane begins to dry out immediately. Changes inside the body and many external influences in daily life can contribute to desiccation.
Drying damages the tissue and irritates the nerve fibers. Damage to the tissue results in it becoming even less wettable. Thus, dry eye can become worse without sufficient treatment. The irritation of the nerve fibers leads to a feeling of irritation and pain - this may be felt on or around or even behind the eye.