In India about four million people are blind due to corneal diseases and every year this number is increasing. 80% of such blind people can be cured by an operation known corneal transplantation. The only source of healthy cornea for transplantation is through donors who decide to donate their eye balls after death. In certain cases, the cornea of a person might become opaque due to different reasons. In such cases this opacity obstructs light to enter inside thus leading to blindness. Clinically, it appears as a white spot in the normally ‘dark’ centre of the eye. Injury, infection, poor nutrition and hereditary disorders are common causes of corneal opacity and subsequent corneal blindness. Corneal transplantation is a surgical procedure where a damaged or diseased cornea is replaced by donated corneal tissue (the graft). When the entire cornea is replaced it is known as penetrating keratoplasty and when only part of the cornea is replaced it is known as lamellar keratoplasty. Keratoplasty simply means surgery to the cornea. The graft is taken from a recently deceased individual with no known diseases or other factors that may affect the chance of survival of the donated tissue or the health of the recipient. Sri Sankaradeva Nethralaya has a fully dedicated Eye Bank and Corneal Transplantation unit in its premises. The Eye Bank performs a number of activities such as –
Provide information regarding Eye Bank
Collection of Eye Balls from donors after death
Preservation of eyeballs
Distribution of eye balls to various eye hospitals
Establishment of eye bank network
Promotion of eye research
The process of corneal transplantation or Keratoplasty can be done under local or general anesthesia. A disk of the opaque cornea of the patient is removed and replaced by a transparent and healthy ‘donor’ cornea collected from the donated eye ball. Depending upon the depth of the corneal opacity, either the full thickness (Penetrating Keratoplasty) or superficial slice of the opaque cornea (Lamellar Keratoplasty) is replaced by transparent donor cornea. Eye donation procedure at Sri Sankaradeva Nethralaya The only source of cornea is from the donated human eye balls. Generally, anybody who wishes to donate his/her eyes after death can do so. However, if any donated cornea is found to be unhealthy, or has a chance of disease transmission from the donor cornea to the recipient, these eye balls are rejected for transplantation. These rejected eye balls are used for various research purposes. As per normal procedure, the willing donor is required to contact a local eye bank and fill the ‘Eye Donation Pledge Card’. In addition to this, the donor should also inform his/her family members and close relatives regarding the pledge so that they can inform any nearby eye bank after the death of the donor. In the case of minors or persons who have not pledged to donate, the immediate family members can decide to take the decision on behalf of the deceased. The donated eye balls are collected generally within six hours after the death of the donor. The surgical removal of the eye tissue is performed soon after death, ensuring the tissue is in the best possible condition for transplant. This also makes sure that the funeral arrangements are not delayed in any way. As such, the eye bank has to be informed immediately after the death of the donor. Once they are informed, the Eye Bank personnel rush to the location of the deceased donor and collect the eye ball by a surgical procedure known as Enucleation. This procedure takes about 15 – 20 minutes time and to avoid any cosmetic deformity, prosthetic eyes are fitted to the face of the deceased. Soon after the removal of the eye ball, it is transported to the eye bank and preserved carefully to maintain the integrity of the corneal tissue. Three different types of preservation are possible and depending upon the mode of preservation the cornea can be transplanted within a specific time. Short term (1 to 3 days), intermediate term (1 to 7 days) and long term (more than 2 – 3 weeks) preservation of the cornea can be done before it is used for transplantation. The preserved eyes are distributed to various hospitals as per their need.
Frequently Asked Questions regarding Corneal Transplantation
The endothelial cells lining the back of the cornea constantly pump water out of the cornea, thus, maintaining its clarity. Damage to the cells due to hereditary diseases, inflammation and various forms of trauma including surgery can allow fluid buildup in the cornea resulting in corneal oedema and loss of clarity. Scars in the cornea following injury or infections contain fibrous tissue and also appear white. When the cornea becomes cloudy, similar to the frosting of glass, light is not able to pass through the eye resulting in poor vision. The only way to restore this vision is to replace the cornea with donated healthy corneal tissue. Obtaining a new cornea is what happens in corneal transplant surgery.
The major corneal disorders which cause poor vision and can be corrected by a corneal transplant are: 1. Corneal edema after cataract extraction and lens implantation - Fluid collects in the cornea with loss of clarity 2. Fuch’s endothelial dystrophy - Genetically determined loss of endothelial cells 3. Keratoconus - Conical protrusion of the cornea causing poor vision 4. Corneal scarring after infections and trauma - Opaque fibrous tissue rejects clear cornea 5. Failed grafts - Failure of a previous corneal transplant 6. Hereditary stromal corneal dystrophies - Genetically determined production of opacities in the clear cornea It is of course understood that in such cases, the eye has only a corneal problem. A corneal transplant will not restore vision if the eye has any retinal or optic nerve disease.
When the corneal abnormality is limited to the anterior portion of the cornea a lamellar (partial thickness) keratoplasty os performed. if the corneal abnormality is involves the deeper layers or the entire cornea, a penetrating (full thickness) keratoplasty is performed Corneal transplants performed to rdid the eye of progressive eye infections are called Therapeutic Keratoplasties.
No. The central part of the diseased host cornea is removed and is replaced by a donor corneal button of similar or slightly larger size. The donor cornea is sutured in place with very fine monofilament nylon suture which is much thinner than a human hair. The cornea is the only part of the eye that can be transplanted.
Yes. Corneal transplantation can be performed along with cataract, glaucoma and vitreous surgery.
Complications following corneal transplantation include hemorrhage, infection, graft rejection, wound dehiscence and astigmatism.
No. Usually an intervening period of one year is advised.
The rate of graft clarity depends on the nature of the patient’s corneal diseases. It is greatest when the host cornea is free of disease or blood vessels. For example, in keratoconus, the success rate is over 95%. In contrast, after a severe chemical burn there is extensive growth of new vessels onto the cornea and a severely damaged ocular surface. The prognosis for for corneal transplantation in such an eye is poor.
Post-operation, the patient is reviewed at 1 , 3 and 6 months after the surgery and at yearly intervals thereafter. Eye drops will need to be used for a period of 6 to 9 months. Suture removal is usually performed after about 6 months. Visual recovery occurs by about the third month after surgery.
Redness, difficulty in facing bright light, sudden decrease in vision, pain, irritation and discharge may be early indications of impending graft rejection or infection. If such symptoms arise, consult your ophthalmologist immediately. Use prescribed eye drops as directed. Bring your medications with you on each visit to your doctor so that he/she may check them and make appropriate adjustments.
Eyes are obtained from the cadaver within 6 hours after death, provided there are no donor contradictions like infections, malignancy or AIDS. Age, race, sex, blood type and eye color are of no importance to the functioning of the cornea. If the eyes are suitable, the cornea is removed along with a small rim of sclera and is placed in special tissue culture solutions designed to keep the cornea viable for 7 – 14 days.
A patient with a corneal problem is first assessed by a corneal surgeon. If it is decided that he/she will benefit by a corneal transplantation procedure, his/her name is registered on a waiting list. The patient is then informed when his/her turn arrives and the surgery can be performed.
Frequently Asked Questions regarding Eye Donation
Anyone can be a donor irrespective of age, sex or blood group.
Yes. All religious beliefs affirm that organ donation, including eye donation, for the benefit of a suffering person is a noble cause.
No. Only the thin transparent layer in front of the iris called the cornea is used for transplant.
No. Both these conditions relate to the lens of the eye and not the cornea.
No. The removal of eyes does not cause disfigurement, nor does it interfere with the customary funeral arrangements.
Corneas do not have any direct blood supply, so the risk of rejection is very low. Rejections, if they occur, can be suppressed by timely medication.
Corneas of persons suffering (in their last days) from AIDS, Jaundice, Rabies, Syphilis, Tetanus, Septicaemia, Viral diseases, Hepatitis B & C, Blood cancer and dengue are considered unfit for donation.
Donors with these conditions can donate their eyes.
After the eyes are removed they will be evaluated, processed, screened and then supplied to the eye surgeon for transplant.
Corneas that, for technical reasons, are not used for vision restoring corneal transplant, are used for research.
No. Transplants only help when the loss of sight is solely due to corneal defect and the rest of the eye’s mechanism (retina and optic nerve) is intact.
As soon as possible. Normally eyes can be removed within 6 hours after death, but in places where the climate is hot, such as ours, a shorter duration, preferably 2 to 4 hours, is advisable
Eye banks have personnel who come to the donor’s home to remove the eyes. The procedure, known as enucleation, takes approximately 30 to 45 minutes. The eye bank can be communicated over telephone about the donation.
An eye bank is the link between the donor and the recipient / eye surgeon. It is an organization recognized by the Government to collect and distribute human eyes to those who require corneal transplants.
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