What Is The Cornea?
The cornea is the transparent dome on the front of the eye, which acts as a window, protecting the inner light-detecting components of the eye. Cornea grafting is used for many corneal diseases but relies on an intact limbal stem cell source in the recipient for long term success.
The limbal stem cells help maintain a clear cornea. The health of the cornea on the front surface of the eye is essential for vision. Deficiency of these stem cells results in corneal inflammation, opacification, vascularisation, pain and loss of vision.
How Can Stem Cells Help Prevent Blindness?
On Tuesday 7th June 2016, the first Limbal Stem Cell transplant in Ireland was performed by Mr William Power, Consultant Ophthalmologist at the Royal Victoria Eye and Ear Hospital (RVEEH) in Dublin.
While this technique has been available in a number of other countries until now this was not a treatment option available in Ireland. This transplant represents the culmination of a collaboration between researchers, scientists and clinicians in the National Institute for Cellular Biotechnology (NICB) in Dublin City University (DCU), the Eye Bank at the Irish Blood Transfusion Service (IBTS), and the Royal Victoria Eye and Ear Hospital (RVEEH).
Other new research led by scientists at Newcastle University, UK reveals a potentially revolutionary way to treat eye injuries and prevent blindness — by softening the tissue hosting the stem cells which then helps repair wounds, inside the body.
The team discovered that the simple application of a tissue-softening enzyme, collagenase, prevents the loss of corneal stem cells following an injury and could prevent patients from losing their sight.
It offers hope to almost 500,000 people a year who lose their sight due to chemical burns including acid attacks.
As the outermost layer of the human eye, the cornea has an important role in focusing vision yet many of the processes keeping it transparent and resistant to damage are not well understood.
Like skin, the cornea is covered by a multi-layered epithelium forming a barrier to physical harm and invading microorganisms. But unlike the skin, when an injury occurs the corneal epithelium is repaired by stem cells clustered in the tissue’s periphery, first by quickly dividing in great numbers and then by migrating towards the damaged site as matured epithelial cells in order to seal the wound.
How Is Corneal Damage Usually Treated?
A cornea transplant is an operation to remove all or part of a damaged cornea and replace it with healthy donor tissue.
A cornea transplant is often referred to as keratoplasty or a corneal graft.
It can be used to improve sight, relieve pain and treat severe infection or damage.
One of the most common reasons for a cornea transplant is a condition called keratoconus, which causes the cornea to change shape.
A cornea transplant can be carried out under general anaesthetic(where you’re unconscious) or local anaesthetic (where the area is numbed and you’re awake).
The procedure usually takes less than an hour and, depending on your circumstances, you either leave the hospital the same day or stay overnight.
If the procedure involves the transplantation of the outer cornea, the new outer cornea is held in place with stitches, which usually stay in for more than 12 months.
An endothelial transplant (EK) doesn’t require stitches. It’s held in place by an air bubble until a few days later when it naturally sticks to the deep layer of the cornea.
After a Corneal Transplant
The recovery time for a cornea transplant depends on the type of transplant you have.
It takes about 18 months to enjoy the final results of a full-thickness transplant, although it’s usually possible to provide glasses or a contact lens much earlier.
Recovery is usually faster after replacing just the outer and middle layers (DALK).
Endothelial transplants (EK) tend to have a faster recovery time of months or even weeks.
It’s important to take good care of your eye to improve your chances of a good recovery.
This means not rubbing your eye and avoiding activities such as contact sports and swimming until you’re told it’s safe.