CHENNAI : Eyes are our windows to the world, and the gift of sight is precious. Sadly, visual impairment remains a harsh reality for millions of people due to cataract, refractive error, glaucoma, age-related macular degeneration and diabetic retinopathy. Another prominent cause is corneal blindness, which is caused by the opacity of the cornea, which in turn leads to blurring and vision loss.
Till a few decades back, people suffering from corneal blindness had no recourse. But thanks to advancements made in medical science, their vision can now be restored with corneal transplantation or keratoplasty, a term used for the surgical replacement of the cornea. However, this procedure is entirely dependent on voluntary eye donation after a person dies. India is home to half of the world’s blind population. Of the 15 million blind people in the country, 6.8 million suffer from corneal blindness, a number that is expected to rise to 10.6 million by 2020.
As many as three million people with total vision impairment can benefit from a corneal transplant, according to an estimate. In a keratoplasty, the affected cornea is removed and replaced with the donor cornea. It is important to harvest the cornea within six hours after the death of the donor. Once the eyeball is procured, it is transferred to an eye bank.
Even after decades of promoting eye donation, the current supply is sufficient to meet only 10 per cent of the total demand. India, a country of 1.2 billion people, saw only 3,000 eye donations in 2015-2016. Lack of awareness and superstition are the main hindrances to eye donation. Inadequate infrastructure for extraction and storage of cornea is another.As National Eye Donation Fortnight comes to an end on September 8, we analyse the myths and processes surrounding eye donation.
Many people believe the soul of a dead person whose eyes have been removed will not attain salvation. Medical personnel harvesting the eyes take care not to change the facial appearance of the deceased. A plastic prosthetic eye is placed in the socket and the eyelids are gently closed to give the face an unaltered appearance.
Eye donation from one person (both eyes) can give the gift of vision to four patients. Anybody can pledge to donate eyes after death, irrespective of age or gender. However, the next of kin has to authorise eye donation of the deceased, even if the deceased had pledged his or her eyes for donation. The next of kin can also permit donation of eyes of the deceased even if he or she did not donate eyes before death. People suffering from diabetes, hypertension, asthma and those without communicable diseases can also donate eyes, as also people blind from retinal or optic nerve diseases.
People suffering from AIDS, Hepatitis B or C, rabies, septicaemia, tetanus, cholera, meningitis or encephalitis cannot donate eyes. Those with frank ocular infection and those who have had a previous refractive surgery cannot donate either. Donation is also not possible if death was caused by drowning or due to unknown causes.
All donated eyes are used in some way and proper records are maintained. While healthy eyes are used to provide vision to the blind, eyes not medically suitable for corneal transplants are used for medical research and education. The form for eye donation is available at all major hospitals and eye banks. It can also be accessed online.
Today, an army of biomedical engineers and scientists globally are striving to develop artificial corneas for transplantation, but this is still at the research stage. The only hope for blind patients is eye donation. If indeed, more people donate eyes in India, blindness can soon be a thing of the past. The author is a consultant ophthalmologist at Dr Agarwal Eye Hospital.
What is the cornea?
The cornea is the clear, transparent layer before the black portion of the eye. It is the main focusing surface which converges light rays as they enter the eye to focus on the retina. It is the most important part of the eye’s optical apparatus. Loss of its transparency results in loss of vision, which may be caused due to infection, injury, malnutrition or congenital/hereditary causes.