Lamellar Corneal Surgery

Blindness due to corneal disease is a potentially devastating condition accounting for 4.6 million blind individuals in India alone, with a large proportion of the affected being children. Corneal transplantation is one of the chief modalities of treatment in such case.

Corneal disease, that could lead to corneal blindness could affect the full thickness of the cornea or could be confined to a partial thickness of the cornea. In either case, conventional corneal transplant, or penetrating keratoplasty involves the replacement of the entire thickness of the cornea. This involves a circular button of healthy corneal tissue from a donor cadaver eye replacing the full thickness corneal tissue from the unhealthy eye, being held together with 16-24 sutures, taking several months to heal and requiring the patient to use medication for about 6-8 months to suppress an immune rejection of the graft. The surface of the cornea is often rendered irregular by the sutured graft, having a deleterious effect on the quality of vision.

In the last decade, a modified form of corneal transplant called Lamellar Keraoplasty has become popular. This involves only a partial thickness of the cornea that is transplanted to selectively replace only the diseased portion leaving the rest of the healthy cornea of the patient undisturbed. It is therefore a less invasive procedure but involves finer surgical skill and more refined instrumentation. Lamellar keratoplasty is of two types:

1. Deep anterior lamellar keratoplasty (DALK)
2. Deep lamellar endothelial keratoplasty (DLEK)

Deep anterior lamellar keratoplasty (DALK) is a partial thickness corneal graft, that is used in eyes where the pathology is confined to the anterior (front) layers of the cornea, eg. Superficial corneal scars and certain congenital or developmental disease. The advantages of this technique over the ‘conventional’ full thickness graft are: fewer sutures, quicker rehabilitation, less medication, almost negligible chances of a graft rejection and a more secure wound.

Deep lamellar endothelial keratolasty (DLEK) is also a partial thickness corneal graft, that is used to replace the innermost layer of the cornea, called the endothelium, which is responsible for maintaining the transparency of the cornea. This layer is often damaged due to complications in cataract surgery, leading to poor vision. DLEK is a more intricate surgical procedure than DALK, and was introduced as recently as 1998 by an innovative Dutch surgeon, Dr. Gerrit Melles and popularized in the US by an Ohio-based surgeon Dr. Mark Terry. The benefits of the technique, over the conventional corneal transplant include a better quality of vision a more comfortable post operative period and a quicker visual rehabilitation. This form of corneal transplant can even be performed through a wound as small as a modern cataract wound and can be done without sutures.

Sankara Nethralaya has always believed in keeping abreast with progress in science and technology, and in taking the lead to bring the best of techniques and technology to patients in this country at an affordable cost. We had Dr Gerrit Melles from Rotterdam, Holland, visit our institution in 2002 and initiate the corneal surgeons at Sankara Nethralaya into the techniques of DALK. This procedure has been performed on several patients by the corneal team, with gratifying results.

Dr. Rajesh Fogla, a member of the team of the corneal surgeons at Sankara Nethralaya received intensive training in the procedure of DLEK, under the tutorship of one of the best known pioneers in this field, Dr. Mark Terry himself. He recently performed a successful DLEK, for the first time in India, bringing this technology to Sankara Nethralaya for the benefit of many more potential candidates for this surgery.

In order to disseminate this knowledge and expertise among our colleagues from different parts of the country, Sankara Nethralaya organized a 2-day international conference on “Lamellar Keratoplasty” of September 4 and 5, 2004. This meeting provided an update and insight into these and other recent advances in corneal surgery. Among the distinguished faculty for this meeting were Dr. Mohammed Anwar from Magrabi Eye & Ear Hospital, Jeddah, Saudi Arabia, and Dr. Mark Terry from Devers Eye Institute, Portland, USA, both world renowned corneal surgeons and pioneers in this particular field of Lamellar Keratoplasty.

Comments

[G. Culver]

Dr. Mark Terry actually is an OREGON - based physician