Amrita Institute of Medical Sciences has been able to offer corneal transplantation to over 190 patients in a short span of time. Corneal transplantation or keratoplasty is the most successful organ transplantation known to medical science. Revolutionary changes in microsurgical techniques and materials have made it a highly rewarding exercise with success rates of 80 -90 % in most cases.
Cornea is a transparent structure like a watch glass, which forms the front part of the eye and has multiple layers. The light rays have to pass through cornea if it has to enter the eye. If the cornea is diseased, it no longer maintains its transparency. Hence the light rays do not reach inside the eye resulting in blindness. Corneal blindness or blindness due to corneal disease can be cured by corneal transplantation, in which diseased cornea is replaced by a normal cornea, obtained through eye donation.
Corneal blindness is a major cause of curable blindness in our country second only to cataract. It is estimated that, in India at least 7 million people are corneal blind people in at least one eye, of whom one million are blind in both the eyes. The main causes of corneal blindness in India are
- Vitamin A deficiency during childhood often associated with measles
- Workplace injury
- Corneal scar following corneal infection
- Corneal oedema following cataract surgery.
It is a frustrating fact that nearly 95% of this corneal blindness is avoidable. Prevention through health promotion strategies and safety in workplaces is most important to deal with corneal blindness in a developing country like India. Once corneal blindness has occurred, in most cases the only treatment option is corneal transplantation or keratoplasty.
Corneal transplantation or Keratoplasty is a well-accepted treatment modality with about 45,000 procedures performed annually in the United States. In India the figure is around 10,000 mainly limited to major ophthalmic institutes.
Keratoplasty is done with any of the following objectives
- Optical - to restore the vision
- Therapeutic - done on an emergency basis, primarily to cure the corneal infection resistant to medical treatment in order to save the eye
- Tectonic - to restore the shape of the eye
Lamellar keratoplasty or selective replacement of pathological corneal layer has revolutionized the scene of corneal transplantation resulting in early visual rehabilitation. And automation [use of a microkeratome for lamellar cut] has brought further precision and refinement to lamellar keratoplasty minimizing the interface haze.
Presently, Amrita Institute of Medical Sciences is the only centre in Kerala to have automated lamellar keratoplasty system [ Amadeus ALTK ] and is useful in both anterior a lamellar and endothelial keratoplasty.
Automated anterior lamellar keratoplasty
For corneal stromal disease, only the anterior stroma can be replaced, the dissection done precisely with a microkeratome, as in LASIK – called automated anterior lamellar keratoplasty. Automated anterior lamellar keratoplasty virtually eliminates interface haze – the main problem with manual dissection. As the endothelium is not replaced there is almost no risk of rejection & need for long-term steroids.
Descemet’s stripping endothelial keratoplasty, the popular form of corneal transplantation for endothelial pathology like pseudophakic bullous keratopathy and Fuch’s endothelial dystrophy can also be performed with ALTK system – Descemet’s stripping automated endothelial keratoplasty [ DSAEK ] .
Therapeutic keratoplasty – can save the eye and can restore vision in a lot of them, if done appropriately and early enough.
After corneal transplantation, multiple check-ups are required and steroid eye drops need to be used for at least a few months. Graft infection, graft rejection or rise in eye pressure are possible which needs immediate treatment. Eye pain, redness, watering, aversion to light or decrease in vision are warning signals which require immediate consultation with a trained eye-specialist.
The number of corneal transplants performed in our country, more so in Kerala is disappointingly low due mainly to lack of public awareness and poor communication between the donor and the transplant team. For proper utilization, the corneal tissue has to be taken from the deceased person within 6 hours by the eye bank personnel. The eye bank usually attached to a major hospital promptly collects the whole eye or cornea on being alerted, stores it and disperses it to the transplant surgeon for timely utilization. The ignorance of lay public, commotion in the family at the time of demise, delay of eye bank personnel to reach the site, limitations of storage all result in wastage of many a cornea.
Storage of cornea in M-K medium is indeed advantageous. In M-K medium, cornea can be kept for 72 to 96 hours which gives us enough time to perform corneal transplantation almost as a planned procedure. With the whole eye, usually stored in moist chamber, transplantation has to be performed preferably within 24 hours and so chances of wastage of tissue are high due to delay in completing the blood tests and in arranging the recipient.
Amrita Eye Bank
At Amrita Eye Bank, the donor cornea is preserved in MK medium in which nutrition of the cornea can be maintained for 4 days, making corneal transplantation a planned procedure. The state–of–the–art facilities at Amrita Eye Bank include specular microscopy and laminar flow hood.