For 40 years, diseases and surgery of the cornea and ocular surface have been a major interest of Eye Health's corneal specialist, Kenneth R. Kenyon, MD. Beginning with a cornea transplant, the first operation he ever witnessed as a medical student, Kenyon has remained devoted to the development of this increasingly important sub-specialty. As Director of the Cornea Service of the Mass. Eye & Ear Infirmary and Associate Professor of Ophthalmology at Harvard Medical School for 12 years prior to joining Eye Health in 1990, he devised, taught and published many of the surgical techniques in this area that are practiced today world-wide. The cornea is the transparent "window" of the eye that permits light to enter the pupil and to focus on the retina to produce clear vision. Normally crystal clear and dome-shaped (like a contact lens), it can become cloudy or misshapen as a consequence of injury, disease or surgical complications, thereby greatly reducing vision.
|Following severe ocular injury, the cornea is scarred by extensive corneal laceration (note sutures), there is extensive iris tissue loss, and the ruptured lens has a milky white cataract||Following corneal transplant plus extensive reconstruction of the iris and cataract removal by Dr. Kenyon, the same eye attains nearly full restoration of vision and appearance.|
The good news is that cornea transplantation (termed keratoplasty) using human donor corneas are the most successful of organ transplants, enjoying a 95% favorable prognosis in most cases. Thanks to the world's best network of eye banks, in the USA approximately 40,000 cornea transplants are performed annually on an elective (i.e. scheduled) basis.
Only the central portion of the cornea is involved in transplantation. The surgeon removes a circular disc of the patient's cornea and replaces it with a similarly sized disc of donor cornea, which is then secured with microscopically fine sutures that are 1/10th the diameter of a human hair. Despite the precision involved, this surgery is performed on an ambulatory outpatient basis and in straightforward cases requires only 30 minutes to complete. In eyes with more substantial abnormalities of the iris and lens, Dr. Kenyon has devised techniques to combine cornea transplants with cataract removal, intraocular lens implantation or exchange, and repair of damage to the iris and pupil. Sutures are removed or adjusted to reduce astigmatism on an individual basis. Thus glasses or contact lens will generally not be prescribed until the transplant has become stable and healed, usually after 3 months.
Apart from the cornea, the other tissues comprising the ocular surface, specifically the conjunctiva (a transparent membrane covering the white of the eye or sclera) and the limbus (immediately adjacent to the cornea and the source of vital stem cells) are also subject to disease or injury. Starting in 1978, Dr. Kenyon devised the surgical technique of conjunctival autograft for treatment of localized conjunctival diseases such as the pterygium (an inflammation of the conjunctiva extending on to the cornea which commonly affects fisherman, construction workers and others exposed to sun & wind), thereby improving the prognosis for cure from 50% to 95%. This surgery has become the technique used universally for treating such disorders. Beginning in 1984, Kenyon then developed the limbus autograft predominantly for eyes that had sustained diffuse ocular surface damage such as by chemical burn. This technique of stem cell transplantation (Figure 2) has also been widely adopted during the past two decades and has improved the success of subsequent corneal transplant in such eyes from 50% to 90%. More recently, operating at the Greater New Bedford Surgicenter, Dr. Kenyon has adapted the technique of amnion membrane transplantation for use in conjunction with corneal transplants to treat eyes with loss of corneal sensation following infection or injury, and has also greatly improved the prognosis for these so-called high-risk keratoplasties. Kenyon's pioneering efforts have been recently recognized in The New York Times and The New England Journal of Medicine, as well as by noted North Dartmouth author, Ann Parson in her recent book about stem cells, "The Proteus Effect" (Joseph Henry Press, 2004).
At Eye Health's Center for Cornea & Ocular Surface Disease, patients are referred both regionally and internationally for evaluation and management. Hundreds of cornea transplants and other ocular surface surgeries have been performed routinely by Dr. Kenyon at the Greater New Bedford Surgicenter with excellent outcomes. As a result, such patients no longer have to be referred to Boston for performance of these sight-restoring procedures.