CORNEAL TRANSPLANT SURGERY: WHAT IS IT?
A corneal transplant involves removing a damaged cornea and replacing it with a donor cornea that is in good condition. The term “Keratoplasty” also applies to this technique.
The colourful iris and circular, black pupil are covered by the cornea, which can be seen as the front window of the eye. We can see because the cornea concentrates the light as it passes through. The most crucial component for clear eyesight is a healthy and clean cornea. The cornea loses its smoothness and ability to see properly if it is scratched, damaged, or ill, which results in distorted, glaring, or blurred vision.
A CORNEA WORK
Our sight comes from our eyes. It is made up of a variety of parts, such as the cornea, iris, pupil, lens, retina, macula, optic nerve, choroid, and vitreous, among others.
The transparent front surface of the eye, known as the Cornea, functions like a camera lens and is principally responsible for concentrating light in human eyes. Clear through the cornea are the colourful iris and the pupil, which is a black dot. In essence, the cornea aids in concentrating incoming light onto the retina, a light-sensitive layer found in the rear of the eye. The picture created at the retina is sent to the brain.
Similar to a camera’s diaphragm, the iris of the eye regulates the quantity of light entering the rear of the eye by automatically altering the pupil’s size.
Accommodation Light is further focused by the crystalline lens of the eye, which is situated right behind the pupil. This lens, which works similarly to an autofocus camera lens, assists the eye in automatically focusing on nearby and approaching objects through a process known as accommodation.
Retinal Light is focused onto the retina via the cornea and crystalline lens. The retina transforms optical pictures into electrical signals, much like a digital camera’s electronic image sensor. The visual cortex, the area of the brain that regulates our sensation of sight, receives these impulses from the optic nerve.
What situations call for a CORNEAL TRANSPLANT?
A corneal transplant can be used to treat a variety of disorders, including the following:
- an outwardly curved cornea (Keratoconus)
- the corneal tissue thinning
- scarring of the cornea brought on by accident or illness
- corneal opacity
- eyelid swelling
- Ocular ulcer
- rare side effects from prior eye surgery
Types of Corneal Transplants
The kind of corneal transplant a patient receives depends on the degree and location of the damage to the cornea. Several varieties of corneal transplants include:
- A full thickness transplant known as penetrating keratoplasty involves resecting the patient’s cornea completely with a trephine of the appropriate diameter, followed by the implantation of a donor corneal graft.
- Deep anterior lamellar keratoplasty (DALK) involves replacing or modifying the cornea’s outer or middle layer. The corneal stroma is selectively transplanted during this partial thickness procedure.
- Endothelial keratoplasty: replacement of cornea’s deep layer. Disorders of the cornea’s innermost layer are treated with this relatively recent technique. In contrast to a conventional corneal transplant, this procedure requires only one or no stitches.
CORNEAL TRANSPLANT SURGERY BENEFITS
- More than 70% of eyesight is corrected.
- Recuperation is rapid
PROCEDURE FOR CORNEAL TRANSPLANT SURGERY
#PRIOR TO THE OPERATION
- Prior to the procedure, the ophthalmologist will perform a number of eye exams to assess the candidate’s suitability for corneal transplant surgery.
- A thorough eye examination is performed by the eye surgeon to look for any conditions that might lead to difficulties in the future.
- Eye measurement: The doctor will determine what size cornea the patient needs.
- Review of all prescription drugs and dietary supplements – All prescription drugs will be carefully examined, and the surgeon may advise patients to cease using certain drugs either before or after surgery.
- Before the procedure, any other eye issues, such as infections, inflammation, etc., must be properly addressed.
- Information regarding medical conditions: The patient must disclose to the surgeon any allergies or medical conditions they may have had in the past.
- The night before the procedure, the patient must refrain from eating anything after midnight. Up to two hours before operation, the patient may have water, juice, tea, or coffee without sugar or cream. Since 24 hours before operation, alcohol consumption must strictly be avoided.
- Wear comfortable clothing the day of the procedure, and avoid wearing jewellery, creams or lotions, or makeup.
#WHEN IN SURGERY
- Under general or local anaesthetic, corneal transplant surgery typically lasts an hour.
- The most popular method of corneal transplant (penetrating keratoplasty) involves the surgeon completely removing the damaged or infected cornea.
- The patient has a little button-shaped corneal disc removed from their eye.
- A precise circular cut in the cornea is made with a trephine, a tool that functions like a cookie cutter.
- To suit the patient’s cornea, a piece of cornea from a donor is trimmed to the same size.
- The graft is held in place by tiny stitches composed of nylon. Instead of nylon, air bubbles are employed in endothelial keratoplasty to maintain the graft in place.
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#AFTER THE OPERATION
- Most patients return home the same day as their operation, but some may need to stay overnight.
- For around 4 days, the patient will need to wear eye patches.
- To promote speedy healing and shield the eye from infection and rejection, the doctor will prescribe eye drops.
- At a later appointment, the doctor will take the sutures out. Some sutures could not be removed at all, while others might last up to a year.
#When Recovering
Since the cornea is thought to be “immunologically privileged,” matching the donor and recipient is not necessary. Your eye drops will aid in preventing rejection of the new cornea without the need for pills or systemic medicine. If only the outer layer of the cornea is transplanted, as opposed to the whole layer or the inner layer, your body is less likely to reject the procedure. Rejection occurs in less than 20% of instances, on average.
COMPLICATIONS WITH CORNEAL TRANSPLANT
The main issues with corneal transplantation include:-
- Rejection: In about one in three transplant patients, the body may reject the transplanted cornea. Steroid eye medications may be able to control this rejection.
- Bleeding
- Glaucoma
- Cataract
- eyelid swelling
- disease of the eyes
- absence of vision
- injury to the eye
RATES OF CORNEAL TRANSPLANT SUCCESSION
- Success rates often vary depending on the issue that has to be resolved with the transplant. According to several studies, a fresh cornea lasts at least 10 years.
- 85% of those who have keratoconus.
- 75% of those who have fuchs dystrophy.
- 60% to 70% of individuals have corneal scarring.
Outlook (prognosis)
It might take up to a year for your eyesight to fully recover. For several years following a successful corneal transplant, most patients enjoy really good eyesight. For better eyesight, the patient could require eyeglasses and contact lenses.
A corneal donor is found
The majority of the cornea utilised in transplants originates from a deceased donor. The patient does not have to wait very long for a corneal transplant, unlike other transplants like kidney, liver, or lung. Compared to other organs, a lot more people ask for an eye donation when they pass away. The cornea from persons who have a number of disorders, such as a central nervous system disorder, a history of eye surgery or infection, another eye ailment, or those who pass away for undetermined reasons, may not be utilised.
Does a donor have to be in top physical condition?
Regardless of vision or the presence of conditions like diabetes or cancer, anybody between the ages of 2 and 75 can donate their eyes. Only HIV, AIDS, active hepatitis, active syphilis, rabies, viral encephalitis, leukemia, active lymphoma, or active meningitis are known to exclude eye donation.