It is done for different purposes.

1- Optical : Primary purpose is being improvement of vision (leucoma, keratoconus etc.)

2- Tectonic: Restoration of altered corneal structure.( thinning, perforation etc.)

3- Therapeutic : Tissue substitution for refractive corneal diseases( non – healing corneal ulcer, pterygium etc.)

4-Cosmetic: Replacement ,without the hope for visual improvement.

Keratoplasty is indicated in patients having corneal scar (leucoma, adherent leucoma),bullous Keratopathy, keratoconus, fuchs and other corneal dystrophies,infective keratitis,and trauma to the eye ,congenital eye scar.

The primary benefit of corneal transplantation or keratoplasty is total restoration of vision.

The risks of corneal transplantation or keratoplasty include:

Astigmatism, which can be caused by a ripple in the tissue during surgery. Corrective lenses may be needed to correct this problem.

Glaucoma (high pressure in the eye that can cause vision loss).

Sometimes, the body rejects the corneal tissue. Medication is given to the patient after the transplant surgery to help their body accept the corneal tissue. In a small number of patients, however, the body rejects the donor cornea, resulting in cloudy vision. If rejection does occur, a second transplant can be performed.

Blindness if the surgery is not successful.

In most instances, the patient will meet with their ophthalmologist for an examination in the weeks or months preceding the surgery. During the exam, the ophthalmologist will examine the eye and diagnose the condition. The doctor will then discuss the condition with the patient, including the different treatment options available.

The doctor will also discuss the risks and benefits of the various options. If the patient elects to proceed with the surgery, the doctor will have the patient sign an informed consent form. The doctor might also perform a physical examination and order lab tests, such as blood work, X-rays, or an EKG.

The surgery date and time will also be set, and the patient will be told where the surgery will take place. Within the United States, the supply of corneas is sufficient to meet the demand for surgery and research purposes. Therefore, unlike other tissues for transplantation, delays and shortages are not an issue.

On the day of the surgery, the patient arrives to either a hospital or an outpatient surgery center, where the procedure will be performed. The patient is given a brief physical examination by the surgical team and is taken to the operating room. In the OT the patient lies down on an operating table and is either given general anesthesia, or local anesthesia and a sedative.

With anesthesia induced, the surgical team prepares the eye to be operated on and drapes the face around the eye. An eyelid speculum is placed to keep the lids open, and some lubrication is placed on the eye to prevent drying. In children, a metal ring is stitched to the sclera which will provide support of the sclera during the procedure.

With traditional full corneal transplant surgery (known as penetrating keratoplasty), a circular portion is removed from the center of the diseased cornea. A matching circular area is removed from the center of a healthy, clear donor cornea, placed into position and sutured into place.

With an EK cornea transplant procedure (endothelial keratoplasty), only the abnormal inner lining of the cornea is removed. A thin disc of donor tissue containing the healthy endothelial cell layer is placed on the back surface of the cornea. An air bubble pushes the endothelial cell layer into place until it heals in an appropriate position.

With a lamellar corneal transplant procedure, the superficial layers of the cornea are removed and replaced with donor tissue. Sutures are used to secure the new tissue into place.

1-Pre operative miosis and hypotony.

2-Anaesthesia and akinesia.

3-Exposure, globe fixation and scleral support (Flieringa ring is used to prevent scleral collapse)

4-Trephination of donor cornea is better from the endothelial side, and should be slightly larger (0.25-0.50mm) than the recipient corneal hole.

5-Trephination of recipient button. It is usually 7.0 to 7.5mm diameter in size.Cutting of the host- button is completed with fine scissors.

6-Management of the iris,lens, vitreous and IOL implantation in selected cases.

7-Graft placement and maintenance of anterior chamber by visco elastic agent.

8-Suturing of the corneal button : the first four sutures, placed at 12, 6, 3, and 9 o clock meridians, are known as cardinal sutures. Subsequent sutures are given with 10-0 nylon(at 75-90% of depth)by continuous or interrupted fashion.

9-Wound margin is checked for fluid leak and iris adherence.

10-Anterior chamber is reformed.

11-Sub-conjunctival injection of dexamethasone and gentamycin.

12-Pad and bandage.

The technique aims at

• Minimal manipulation of the donor tissue.
• Protection of the intra ocular structures of the recepient.
• Attaining a water tight junction at the end.

The surgery is a day care surgery. The prognosis for visual restoration and maintenance of ocular health with corneal transplants is generally very good. Risks for failure or guarded prognoses are multifactorial. The type of transplant, the disease state requiring the procedure, the health of the other parts of the recipient eye and even the health of the donor tissue may all confer a more or less favorable prognosis.

The majority of corneal transplants result in significant improvement in visual function for many years or a lifetime. In cases of rejection or transplant failure, the surgery generally can be repeated.

Total cornea transplant recovery time can be up to a year or longer. Initially, your vision will be blurry for the first few months — and in some cases may be worse than it was before — while your eye gets used to its new cornea.

As your vision improves, you gradually will be able to return to your normal daily activities. For the first several weeks, heavy exercise and lifting are prohibited. However, you should be able to return to work within a week after surgery, depending on your job and how quickly your vision improves.

Steroid eye drops will be prescribed for several months to help your body accept the new corneal graft, as well as other medications to help control infection, discomfort and swelling. You should keep your eye protected at all times by wearing a shield or a pair of eyeglasses so that nothing inadvertently bumps or enters your eye.

If stitches were used in your surgery, they usually are removed three to 17 months post- surgery, depending on the health of your eye and the rate of healing. Adjustments can be made to the sutures surrounding the new corneal tissue to help reduce the amount of astigmatism resulting from an irregular eye surface.

The precautions should be followed as per doctors advise.

• Poor graft centration
• Irregular trephination
• Damage to the lens
• Damage to the donor tissue
• Choroidal hemorrhage and effusion
• Incarceration of iris tissue in the wound
• Vitreous in the anterior chamber

Postoperative Complications

• Wound leak
• Glaucoma
• Endopthalmitis
• Primary Endothelial failure
• Persistent epithelial defect
• Microbial Keratitis
• Late failure
• Recurrence of primary disease

Graft Rejection.

The prognosis for visual restoration and maintenance of ocular health with corneal transplants is generally very good. Risks for failure or guarded prognoses are multifactorial. The type of transplant, the disease state requiring the procedure, the health of the other parts of the recipient eye and even the health of the donor tissue may all confer a more or less favorable prognosis.

The majority of corneal transplants result in significant improvement in visual function for many years or a lifetime. In cases of rejection generally can be repeated.