In this method, used particlularly in the stages II-III of keratoconus, a disc obtained from a donor cornea is sewn onto the cornea of the patient without changing his/her tissue. Depending on the needs of the refractive power of the patient's eye, the disc is carved with an Excimer Laser in its optical power. Therefore, Epikeratophakia is namend "living contact lens". After the removal of the outermost protective layer - of the epithelium - this new button is sewn to the patient's eye. Here, a fine circular cut is made with the Guided Trephine System or the Femtosecond Laser to fixate the disc, which should heal without a step on the patient's cornea. Advantages of EPI:
- The subject's cornea is preserved.
- Refraction (short/far sightedness and astigmatism) may be corrected within the same operation. Remaining refractive errors may be treated later with the Excimer Laser from the outside using the PRK technique.
-Reversible: if the result is insufficient, the button can be removed under local anaesthesia.
The donor cornea is fastened with two circumferential threads - the double running antitorque suture, which are removed after about 1 year. Complications may happen extremely rarely (< 3%) . The rejection of the disc may occur, in which case the application of a second button should be performed. Rejection of several discs have not yet ocurred but is theoretically possible. There is the possibility of infection, as may happen with any surgical intervention which can be controlled by administrating antibiotics. This method is a procedure chosen to preserve the patient's eye. In case this measure does not bring the desired resul, if warping and scarring of the cornea are too far advanced, the DALK or PKP procedure are required.