“Sir, the batteries of your television’s remote control have gone bad. We will have to replace your television set.”
Wouldn’t you kick out a technician who asks you to change the whole when you can very easily change just the part?
Similarly, when it comes to your eye, there are many conditions where it is only the single-cell thick layer of your cornea called the endothelial layer which is at fault. Why would you want to change your entire cornea just for one layer?
The cornea is the outer dome shaped transparent surface of your eye. The cornea is made up of five layers namely Corneal Epithelium, Bowman’s layer, Stroma, Descemet’s membrane and Endothelium.
Corneal Transplant or Keratoplasty is a surgery where your damaged cornea is replaced with a healthy one from a donor. This may involve the entire cornea (called full thickness transplant) or a part of the cornea (called partial thickness transplant). Descemet’s Stripping Automated Endothelial Keratoplasty (DSAEK) or DSEK is a type of partial thickness corneal transplant in which the damaged inner cells of your cornea are stripped and replaced with that of a donor’s.
Corneal endothelial cells are responsible for pumping out fluid from the cornea. Due to improper functioning of the endothelial layer there may be water logging in the cornea. This water logging called as corneal oedema causes deterioration of vision and formation of blisters (bullous keratopathy). It is for this condition that DSAEK is performed.
This failure of endothelial cell functioning is seen in:
• Fuch’s dystrophy: A genetic disorder
• After eye surgery like extraction of cataract
Prior to your surgery, your doctor will evaluate your eye to determine the technique that would be best suited for your eyes. Appropriate medications may be advised. DSAEK is an outpatient procedure that does not require you to stay in the hospital overnight. It is generally performed using a local anesthetic to numb your eyes. A small cut is made at the edge of your cornea. Then the layer of damaged cells is removed. After this, the required portion of the donor’s cornea is folded and placed inside your eye. An air bubble is then injected into your eye to unfold the donor tissue and keep it pressed into place.
The donor tissue layer is prepared for use either manually (when the surgery is called DSEK) or using an artificial anterior chamber and microkeratome (a cutting device) and this is when the surgery is called DSAEK.
The entire procedure does not take more than 60 – 90 minutes.
For about an hour after surgery, you will be required to lie flat on your back so that the air bubble can hold the new corneal tissue in position and help it stick to your cornea. You will also be asked to lie flat on your back as much as possible for the next 24 hours. The gas bubble will slowly get absorbed on its own.
Avoid rubbing your eyes in the first few weeks after the operation to prevent the graft from getting displaced.
Steroid drops may be prescribed to reduce the risk of rejection and decrease the inflammation. These should be used only as prescribed.
You would be required to follow up one day after the surgery, one week later, three weeks later and /or as advised by your surgeon.
• Lift other graft surgeries; there is the risk of graft rejection.
• It may so happen that the endothelial cells never function or function for a while and then stop functioning. This is called graft failure.
• Bleeding or Infection inside your eye
• Glaucoma or raised pressure inside your eye
• Complications due to the anesthesia like droopy eyelids or damage to your optic nerve.
IN DSEK / DSAEK, only the thin inner layer of your cornea is replaced rather than the entire thickness of cornea as in traditional corneal transplant. Since the entire cornea is left intact, the chances of astigmatism (refractive error due to irregular surface) is drastically reduced. Also, no or at the most 2-3 stitches are needed as compared to 14-16 in conventional surgery. It also ensures faster recovery. Since all the corneal nerves are not cut in DSEK, surface problems like irritation, blurred vision and erosions are markedly less.
Vision improves faster than that in conventional corneal transplant. Your final visual results will be seen in about 1 to 6 months after surgery. Glasses may be prescribed as required in the course of the checkups after the surgery.