Corneal transplant

Corneal transplant (Keratoplasty)

The cornea is a transparent front surface of the eye that covers the iris and pupil. Light must first pass through the cornea to enter the eye and reach the retina. The cornea refracts the light so that images of objects far-away and close-up are focus on the retina. Therefore, the transparency of the cornea is very essential for vision.

Corneal transplantation is a type of surgery in which a damaged corneal tissue is removed and replaced with a new, healthy corneal tissue. Corneal transplant is usually done for one of the following reasons:

• Improves vision in cases where corneal opacity causes blurred vision
• Repair of corneal perforation to protect the internal structure of the eyeball
• Treatment of eye pain in cases of severe pain due to corneal disease
• Eradication of corneal infection in cases where it is not treated with medication
• Vision correction in cases where regular glasses or contact lenses do not provide satisfactory vision

What disorders may require a corneal transplant?

• corneal edema following other ocular surgeries such as cataract surgery
• keratoconus or increase in corneal curvature
• inherited corneal disorders, such as Fuchs dystrophy
• corneal ulcers following herpes simplex virus (HSV) infection
• scarring caused by corneal injuries such as chemical burns
• Graft rejection after the first corneal transplant

Corneal transplantation is done in two ways:

Full-thickness corneal transplant (PK or Penetrating Keratoplasty): In this method the all layers of the cornea in the affected part is removed and replaced with a healthy cornea.

Partial thickness corneal transplant (endothelial keratoplasty): In this surgery only the affected layers of corneal tissue are removed and replaced with the same layer of the cornea. For example, if the corneal staining only involves the superficial layers, these layers can be removed and replaced with the appropriate layer of the donated cornea.

Where does a transplanted cornea come from?

A transplanted cornea comes from the eye of those deceased individuals who have already expressed a willingness to donate their corneas or their families agree to it. Donated corneas are carefully examined in eye-bank to ensure their health. In addition, all transplanted corneas are screened for infectious diseases such as AIDS and hepatitis so that they are not transmitted to the recipient. These corneas are then preserved in the eye bank for donating to the person in need.

Different stages of corneal transplantation:

Before surgery:  For a corneal transplant surgery the patient is usually admitted on the day of surgery, before the hospitalization, however, cornea booking is coordinated with the eye bank.

Surgery Day:  Corneal transplantation is usually performed under general anesthesia. But if there is no possibility of general anesthesia due to other diseases such as heart or lung problems, the patient gets relaxed with medicine and then the eye becomes numb with local anesthetic (numbing medicine). In this procedure, the patient is awake, but does not feel any pain.

During surgery:  When performing a full-thickness corneal transplant, using microscopic instruments, the surgeon removes a round tissue from the middle of the patient’s cornea and replaces it with an appropriate round tissue of the healthy donor cornea and then sutures it delicately to the eye. To perform a partial thickness corneal transplant, using very exquisite blades or automatic blades (microkeratome), the affected or damaged layer of the patient’s corneal tissue is removed and replaced with a healthy corneal tissue of the donor cornea and If needed attached in place with microscopic sutures. Nowadays, with the advent and evolution of femtosecond laser technology, this type of laser is used to make the corneal flap in most corneal transplantations. The surgery takes one to two hours.

After surgery:  Usually after surgery the patients feel pain and discomfort after waking up that is normal and should not be a concern. Eye bandage is opened the day after surgery and the eye is examined. You have blurred vision on the first day after surgery. Blurred vision gradually and slowly improves, so you should not expect a good vision in the first few days and weeks after the surgery. Pain, sensitivity, and watering of the eye usually improve after 3 to 4 days. The patient is usually discharged from hospital on the day of surgery; however, it may be necessary to have a doctor exam every few days for 3 to 4 weeks.

Postoperative care

Immediately after corneal transplantation, the eye is highly susceptible to trauma and may be seriously injured even with a mild trauma. Therefore, in the first weeks after transplant, you need to follow the following tips:

• Be sure to use a plastic eye shield to prevent impact.
• Avoid bending, pushing and lifting heavy objects.
• You should not bend your head forward during this time. If you have to pick something up from the ground, do not bend, but lean your knees and keep your head straight.
• In the first few days, in case you need a hair wash make sure to keep water and shampoo out of your eye.
• The only exercise allowed during this period is light walking.
• Avoid rubbing and scratching your eyes during this period.

You can get back to your work after two weeks if you do an office work and you mainly do your work sitting, but if your job requires physical activity, you have to wait at least 4 weeks to get back to work.