Dry eye

Dry eye

Dry eye syndrome is one of the most common eye diseases and is normally observed in both eyes. Mostly, it is caused by reduced function of the lacrimal glands. In this condition, the aqeous middle layer of the tear is reduced. This reduced function is observed mostly in women rather than men, because estrogen affects the production of tear. Dry eye generally occurs after menopause. However, many women suffer from this disease before menopause as well as men. Dry eye may be one of the symptoms of rheumatic diseases. Other causes include drug side effects and allergic reactions to certain substances.

The mucous layer of the tear (mucin) is found directly on the eye and is released from specific cells found in the conjunctival layer (goblet cells). Severe inflammation or injury of the conjunctival layer may destruct these cells, causing defective mucin production, which results in dry eye to occur. If the upper adipose layer of the tear weakens due to inflammation of eyelid glands that produce fat or inflammation of the eyelid (blepharitis), the tear evaporates early. Dry eye may also occur in this way. When the tear is distributed unevenly due to eyelid shape or scars, dry eye may be observed.

The most common symptoms of dry eye is burning and stinging. Most of the time, fluid comes from the glands of the eyelid and from the conjunctival glands. Itching and photosensitivity are observed more rarely. Rubbing and wiping the eyes worsen the sense of dryness and closing the eyes decreases the symptoms. When one works by focusing on a screen or reads a lot, the eyelid is involuntarily blinks less. In this case, more intensive complaints occur. The eyes may get dry in cooled and heated rooms. Although the complaints are intensive, they do not jeopardize vision. In rare cases, the corneal surface gets dry, which may decrease visual acuity.

To test for dry eye, the Schirmer test is performed to determine the amount of tear. Here, a small band which is composed of a special paper is placed in the conjunctival sac of the lower eyelid. After five minutes, the amount of moisture is measured. If the distance is very short, there is a possibility of dry eye and other tests should be performed.

It is generally not possible to treat the causes of dry eye. Mostly, treatment is applied as artifical tear in the form of eye drop. These eye drops should be used a few times a day.