Risks and complications
The most frequent complication after Lasik surgery manifests itself in the form of dry eyes. This disorder manifests itself as a deterioration of vision, but a feeling of dryness tends to recede into the background. This is due to the destruction of the nerve fibers supplying the cornea (denervation) during Lasik surgery.
In most cases, however, this recovers within a period of up to six months after the operation. Until this time, artificial tear substitutes should be used to moisten the eyes. During the night, the use of gels or ointments to moisturize the eyes is recommended.
Furthermore, contrast vision can be impaired as a result of Lasik. This manifests itself as deterioration of vision at dusk or at night. A further risk of Lasik are cutting errors.
The piece of cornea (flap) can be cut too small or too thin with the microkeratome or even be completely separated. In the meantime, however, the rate for this complication is only 0.5%. Furthermore, a so-called epithelial defect can occur in the course of a Lasik.
This is a defect of the uppermost layer of the cornea (epithelium). The risk for this complication of Lasik is increased by an early or excessive use of anesthetics during the operation or by insufficient moistening of the eye during the operation. Patients suffering from very dry eyes or changes in the corneal tissue (corneal dystrophy) are also at increased risk of suffering an epithelial defect after Lasik.
If such a defect is present, it is treated with a bandage lens placed over the eye and with an increased dose of steroid eye drops after Lasik. As a further complication, wrinkles can form in the flap after the Lasik procedure. Small wrinkles (micro wrinkles) occur mainly in patients who are treated for severe myopia.
Usually, however, these small wrinkles appear without symptoms. In contrast, large wrinkles (macro wrinkles) in the flap must be surgically removed immediately after Lasik. For this purpose, the flap is separated again, stretched, so that the wrinkles spread and reattached.
In severe cases, however, removal of the wrinkles or temporary suturing for a few weeks may also be necessary. In up to two percent of cases, an inflammatory change in the cornea, a diffuse lamellar keratitis, can occur after Lasik. “Keratitis” refers to inflammation of the cornea and “diffuse” to a random, extensive distribution of this inflammation.
It is often caused by a defect in the corneal epithelium, bacteria or residues in the space (interface) between flap and corneal tissue. This complication of Lasik is treated with steroid drops, steroid tablets or irrigation. An inflammation caused by the pathogen – microbial keratitis – is also a risk of Lasik surgery.
As measures, antibiotic therapy in combination with thorough irrigation below the raised flap should be undertaken. It may even be necessary to remove the flap completely. In rare cases, glaucoma can occur after Lasik surgery, which is an increase in intraocular pressure.
This occurs as a result of steroid therapy after Lasik. Furthermore, the superficial corneal epithelium can grow in the area of the corneal incision. This complication of Lasik develops in about one percent of the treated cases.
However, as long as there is no worsening (progression), this complication does not need to be treated due to the lack of symptoms. If a too thin corneal remnant remains after the corneal ablation within the framework of Lasik, a corneal ectasia can occur, which is understood to be a protrusion of this remnant. If such a case occurs, lenses must be adapted for stabilization, so-called Ferrara rings must be inserted into the corneal tissue or a keratoplasty (corneal transplant) must be performed.
