Corneal transplantation (DMEK)
The cornea is the transparent "windscreen" of the eye. It needs to be clear in order for visual images to be passed to the back of the eye (retina) without obstruction. So in order to see well, the cornea must be free from any kind of vessels, and must remain transparent.
This important task is the responsibility of the inner layer of the cornea, the endothelium. These cells work like "pump cells": they are constantly removing liquid from the cornea to ensure it remains transparent.
A number of diseases, both congenital and acquired, can cause the cornea to become cloudy and the vision to deteriorate to the point of blindness. In about half of all patients, this cloudiness is due to a problem in the endothelium. As the corneal endothelium cells continue to deteriorate, more and more liquid flows into the corneal stroma (the main layer of the cornea). This in turn leads to a gradual reduction in visual acuity, a marked sensitivity to glare, and above all to fluctuations in visual acuity in the early hours of the morning.
Univ.- Prof. Dr. Claus Cursiefen
Transplantation to save sight
As the corneal endothelium is unable to regenerate, in these cases the only way to restore the function of the inner layer is a corneal transplant. Apart from diseases of the endothelium, other cases where the only solution is a transplant include infections and injuries, and congenital or acquired anomalies of the cornea (e.g. keratokonus).
New surgical techniques
The Eye Center Cologne, the center of ophthalmology at the University Clinic of Cologne, has excellent diagnostic and surgical expertise in the field of corneal surgery. Until only recently, the gold standard in endothelial corneal disease was the drastic corneal transplant (penetrating keratoplasty). However, minimally invasive procedures have moved into the spotlight as new developments have been made over the years in the techniques for lamellar corneal transplants. The most recent development is the isolated transplantation of the Descemet’s membrane with endothelial cells, also called DMEK (Descemet Membrane Endothelial Keratoplasty).
DMEK is a gentle and effective method of treating diseases of the corneal endothelium. In DMEK surgery, only the diseased inner layer of the cornea is replaced, and not the entire cornea. Vision improves more quickly after this method than with total replacement of the cornea, and the surgery causes less corneal distortion (astigmatism).
Eye Center Cologne in the lead
The University Clinic Cologne performs about 600 corneal transplants a year, which regularly puts it in one of the leading positions in Germany. Nationally and internationally, the Eye Center Cologne is one of the centers with the most experience in this type of surgery and the highest transplant figures involving the cornea. More than 10% of all corneal transplantations are performed at the Eye Center of the University Hospital Cologne.
Artificial cornea: Boston Keratoprosthesis and new research project by the European Union
One treatment option for restoring visual acuity in patients with the most serious diseases of the surface of the eye (for instance after repeated transplant failures, after acid burns or in association with immunological diseases of the surface of the eye) is the use of artificial corneas. The Eye Center Cologne as the center of ophthalmology at the University Clinic of Cologne offers the implantation of keratoprostheses (e.g. the Boston Keratoprosthesis).
The Eye Center Cologne at the University Clinic of Cologne is also running a Europe-wide research project with the aim of developing innovative new options to provide the most seriously diseased eyes with "biocorneas".
This research project is being supported by the European Union for four years, and aims to develop "bioartificial" corneas made from collagens that will over time be taken on by the host cornea, thereby avoiding possible rejection.