Genetic Engineering

Keratoprosthesis is a surgical procedure where a diseased cornea is replaced with an artificial cornea. Traditionally, keratoprosthesis is recommended after a person has had a failure of one or more donor corneal transplants.[1] More recently, a less invasive, non-penetrating artificial cornea has been developed which can be used in more routine cases of corneal blindness. While conventional cornea transplant uses donor tissue for transplant, an artificial cornea is used in the Keratoprosthesis procedure. The surgery is performed to restore vision in patients suffering from severely damaged cornea due to congenital birth defects, infections, injuries and burns.Keratoprotheses are made of clear plastic with excellent tissue tolerance and optical properties. They vary in design, size and even the implantation techniques may differ across different treatment centers. The procedure is done by ophthalmologists, often on an outpatient basis.The idea of artificial cornea was first proposed in 1789 by French ophthalmologist Guillaume Pellier de Quengsy. On the day of the procedure, the patient will arrive to the hospital or laser center where the surgery is to be performed. After a brief physical examination, he/she will be taken to the operating room. General anesthesia or local anesthesia is given before the surgery begins.An eyelid speculum is used to keep the eye open throughout the surgery. Some lubrication may be used to prevent the eye from drying. Depending on the type of keratoprosthesis used, the surgery may involve a full thickness replacement of the cornea or the placement of an intralamellar implant. For the Alphacor a manual incision is used to create a corneal pocket and a punch is used to create an opening through the posterior cornea into the anterior chamber. The Alphacor is then inserted into the corneal pocket to allow for bio-integration after several months, a second procedure is used to remove part of the anterior cornea to allow light to reach the retina. In the case of the KeraKlear, the intralamellar pocket is created with a femtosecond laser or a corneal pocket making microkeratome. The posterior cornea is left intact.Typically, there is a follow up session few days after surgery, when patients’ complaints are addressed and modifications are made, if needed.Since Keratoprosthesis surgeries are evolving, constant attempts are being made to improve the outcome of the surgery. Also, the material and design used in the artificial cornea may vary and as a result of this, there can be minor variations in surgical procedure as well.