Researchers Develop Artificial Cornea

Around 10 million people worldwide are blind due to corneal damage or disease. In the hopes of saving millions of eyesight, researchers at the Fraunhofer Institute for Applied Polymer Research IAP in Potsdam and the Department of Ophthalmology at the University Hospital of Regensburg, working together with the EU-funded CORNEA project, have developed an artificial cornea which is set for clinical testing early in 2008.

According to the Fraunhofer press release, a person suffering from cornea damage due to congenital malformation, hereditary disease, or corrosion has a risk of going blind. A common solution is to implant a cornea from a donor, however, donor corneas are in short supply. Implanting a cornea involves cutting the natural cornea in a circular fashion and replacing it with a new cornea that is sutured into place. In Germany alone, 7000 people wait for new corneas while in Europe, an estimated 40,000 people wait for a donor. These people wait but often in vain since there is a shortage of donor corneas. Due to this shortage, there have been attempts in creating artificial corneas but many research met with little success.

Most failed attempts at artificial corneas is due to the requirements imposed upon the material. The material on the edge of the artificial cornea must grow firmly into the natural tissue to attach itself but it must also not allow cells to deposit on the center of the artificial cornea as this will impede the patient's vision.

The researchers at Fraunhofer and Regensburg have found a solution. The researchers' artificial corneas are made from commercially available polymer that doesn't absorb water so no cells can grown on it. The artificial cornea is also coated with masks and special protein is coated on the edge of the artificial corneas. The special protein allows cells on the natural cornea to latch unto the artificial cornea to keep it intact but the center of the artificial cornea is free from the special protein so no cells can grow unto it.

IAP project manager Dr. Joachim Storsberg says that what is special about the protein is that in can survive thermal sterilization of the artificial cornea because it does not have a three-dimensional structure that is common in large proteins. If the proteins used are three-dimensional, it would be destroyed in the sterilization process and would lead to changes in the properties of the material. The scientists coated the optical part of the cornea implant with hydrophilic polymer so that it can be constantly moistened with tear fluid.

The scientists' artificial corneas have already been tested on rabbit's eyes and if further tests are successful, it will be tested in humans in 2008.

SOURCE:

Fraunhofer-Gesellschaft, "Artifical Cornea Saves Eyesight." Frauhofer.de