Within our country, we have an average of 15 million blind people of which 75 per cent possess preventable blindness. After cataract, refractive errors and glaucoma, corneal blindness is a leading cause of avoidable blindness.
Cornea is the outermost transparent dome like structure of our eye which lies in front of the pupil through which all light enters our eye and helps us to see. It is composed of 6 layers, each one contributing in its special way to keep the cornea clear.
There are various factors that lead to corneal blindness including Vitamin A deficiency, Hereditary diseases, Corneal Dystrophies and Keratoconus. Scarring is caused as an aftereffect of bacterial, fungal or viral infections and trauma. Chemical injuries and post-surgical complications leading to decompensation.
A detailed evaluation by an ophthalmologist is vital to identify the issue. The grade of scar will determine your treatment options. They could give you glasses or contact lenses if your vision is reasonably good. For people who have a very poor quality of vision, surgery would be a better option.
Even today there is a lot of misconception about what exactly an eye transplant is. A lot of people believe that the whole eyeball is being transplanted which is not the case. The only part of the eye which we transplant is the cornea. We retrieve this from donor within 6 hours of their demise.
Thanks to the advancements in medical science which has paved way for surgeries that involves just replacing the particular damaged layer instead of complete cornea. The options we have are the traditional Penetrating Keratoplasty where all six layers of the cornea are transplanted. The chances of rejection are higher in this type of surgery because of the immune system.
There are lamellar surgeries called DALK (Deep Anterior Lamellar Keratoplasty) where only the front layers of the cornea which are scarred are transplanted. The recovery period is much faster compared to full thickness and also chances of rejection are low. The most common indication for DALK is Keratoconus.
In endothelial surgeries like DSEK (Descemets Stripping Endothelial Keratoplasty), DMEK (Descemet Membrane Endothelial Keratoplasty) and PDEK (Predescemetic Endothelial Keratoplasty) we transplant the innermost layer of the eye which is not functioning well.
The thickness of the Endothelial grafts is as thin as 15 microns in DMEK and 25 microns in a PDEK surgery. As a result, the recovery and visual rehabilitation is also much prior compared to conventional surgeries. PDEK has the added advantage of using young donor corneas which increases the reserve of Endothelial cells transplanted. A decreased number of sutures and an intact surface gives much faster corneal rehabilitation, less post-operative complications and better quality of vision.
In certain cases, the innermost layer of cornea alone is damaged due to conditions like Fuchs dystrophy or post cataract surgery and as a result the endothelial cells which play an important role in maintaining corneal transparency are damaged leading to fluid accumulation and swelling of cornea. This in turn affects the patient’s vision.
Corneal surgeries have a very high success rate among transplants. Post-surgery you will have to be under close follow-up with your ophthalmologist. You will be put on topical medications. The sutures will be removed as and when the healing is complete in a case of Penetrating Keratoplasty. In endothelial surgeries the number of sutures will be minimal.
Please do not ignore any corneal opacity or difficulty in seeing in children as their early identification and treatment will avoid the child from becoming permanently visually impaired. It is also important to check each eye individually in order to not miss a condition affecting only one eye.
The number of corneal blind people keep increasing every year but the number of eyes donated per year does not meet the demand, as a result the waiting list keeps growing over India. However, state of the art eye banks have now helped bridge this gap by increasing the quality of eyes transplanted as well as through use of the newer Lamellar Keratoplasty techniques.
The onus to spread awareness about the importance of eye donation lies in each and every individual. Let us all come forward to pledge our eyes and give the gift of sight to those who deserve it.