LASIK
LASIK stands for “laser in situ keratomileusis” and is currently the most frequently applied laser therapy for ametropia worldwide. The complication of dry eye is now a well-known consequence and frequently occurring side effect of the operation, which can also develop into chronic post-LASIK dry eye (i.e. a corneal disease caused by damaged nerves).
Causes
Why can a chronic tear film disorder occur after laser surgery? It is possible that the patient already had slightly dry eyes before the operation, which are then further aggravated by the operation. The most severely affected patients, who suffer from dry eyes after LASIK surgery, usually have an ocular surface disorder caused by the surgery. This is caused by the severing of the nerves of the cornea during the operation and thus a loss of sensitivity of the corneal surface, which in turn leads to the fact that the feedback of the eye surface to the lacrimal glands (meibomian glands) does not function properly if there is too little tear fluid on the eye. This leads to an inflammation of the permanently irritated cornea and the symptoms of a classic dry eye, such as
- Burning
- Foreign body sensation
- Tiredness of the eyes
- Heaviness of the eyelids
Changes in the eye due to LASIK surgery
Changes in the conjunctiva: Immediately after the operation there is a loss of the so-called goblet cells, which produce the tear fluid indispensable for the eye. This leads to an unstable tear film. This condition usually persists for about 6 months after the operation. The so-called break-up time (BUT), i.e. the tear break-up time, is shortened after LASIK and the Schirmer test, which tests the tear secretion of the large lacrimal gland, can also show a slightly reduced secretion. In addition, osmolarity is increased after LASIK and also after PRK (photorefractive keratectomy).