Surface changes in the eye by LASIK | Dry eyes after LASIK

Surface changes in the eye by LASIK

The LASIK procedure can change the contour of the surface of the eye, which can make it difficult to evenly wet the cornea with tear fluid. Particularly at risk are highly short-sighted patients in whom laser treatment must be performed deep into the cornea to correct the defective vision. It can be assumed that the associated loss of sensitivity is due to deep nerve damage. It has been shown that an incision in the cornea of the eye made during surgery with a knife (microkeratome) leads to a greater nerve-related loss of sensitivity of the eye surface and an increased disturbance of the tear film than is the case with a laser (femtosecond laser).

Risk factors for tear film disorders after LASIK

Long-term contact lens wearers usually already have permanent damage to the corneal surface due to a mechanical disturbance of the natural tear film. Patients with dry eyes already existing before the operation and a Schirmer test of less than 10mm per 5 minutes are also particularly at risk of suffering from a persistent tear film disorder after the LASIK procedure. According to many observations, other risk factors appear to be the female sex (especially after menopause), advanced age and Asian origin. Due to the severed nerve fibers (subbasal nerves) during the operation, many patients develop reduced corneal sensitivity, which should, however, return to normal within 6-12 months. One study found that LASIK surgery on the eye seems to permanently reduce the frequency of eyelid blinking by 40%, which can also lead to dry eyes, as the tear fluid is normally evenly distributed on the surface of the eye by regular eyelid blinking.

Diagnostics to be performed before LASIK surgery:

Before such a cosmetic procedure on the eye, it is important to examine the quality of the tear film and the eye surface in detail. Additional risk factors for a tear film disorder have to be examined, including eyelid inflammation and local medication.