Introduction
The cornea is the transparent clear layer covering the front of the eye. The cornea comprises cells and proteins that protect the eye and provide good vision. The ophthalmologist may suggest a corneal transplant if the cornea cannot be cured or fixed. A healthy cornea from a healthy donor can be used to replace the damaged cornea in this situation. Individuals who decide to provide their corneas to others in need after passing away are referred to as human donors.
Why Is a Corneal Transplant Needed?
Eye diseases and trauma can damage the cornea causing corneal problems. These corneal problems in the long term may need replacement with a new corneal layer (corneal transplant). In addition, the following common vision problems may result in a damaged cornea requiring corneal transplants–
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Keratoconus - The cornea is shaped more like a cone than a dome in keratoconus.
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Fuchs' Dystrophy - Improper working of cornea's inner cells layer of the cornea (endothelium).
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Infections - Inflammation brought on by conditions like allergies, asthma, or eye infections can damage the corneal tissue.
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Eye Injuries - The cornea was injured by prior corneal surgery or eye surgery.
What Is a Corneal Transplantation?
A cornea transplantation is a surgical procedure that involves replacing a portion of the diseased cornea with corneal tissue from a donor. Keratoplasty is another name for this procedure. The transparent, dome-shaped surface of the eye is called the cornea. Through the cornea, light enters the eye. Therefore, it significantly influences how the eye can see. The aims of a corneal transplant involve:
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Restore vision with corneal transplantation.
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Lessen pain.
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Enhance the appearance of a cornea that has been injured or is sick.
In What Situation Is Corneal Transplantation Performed?
Corneal transplantation is performed where medicines, conservative keratoconus surgery, and cross-linking can no longer heal the cornea; corneal transplantation is the only option.
What Is the Source of Graft Used for Corneal Transplantation?
The donor is either a recently dead person with no known diseases or an eye bank. A nearby eye bank processes and tests the donated cornea to ensure it is suitable for surgery. The donation must be made within six hours of the death.
What Are the Indications of Corneal Transplantation?
Corneal transplantation is indicated in -
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Cosmetic - Corneal transplantation can be done on people with corneal scars to enhance their appearance.
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Therapeutic - When the corneal tissue is irritated and not responding, a corneal transplant is an option.
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Optical - To improve the patient's eyesight by substituting clear, healthy donor tissue for opaque or deformed host tissue, as in the case of keratoconus or trauma-related scarring.
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Reconstructive - To maintain the integrity and anatomy of the cornea in patients with stroma (inner cellular of the cornea) thinning.
What Are the Risk Factors for Corneal Transplantation?
The risk factor for corneal transplantation includes:
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The human immunodeficiency virus (HIV), viral hepatitis, syphilis, congenital rubella, tuberculosis, septicemia, and active malaria are among the illnesses that can be present.
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Fatality (Death) with no recognized reason.
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A history of prostitution, intravenous drug abuse, sex with an HIV-positive person, or other high-risk behaviors for HIV and hepatitis.
What Is the Procedure of Corneal Transplantation?
The doctor will perform a physical examination of the patient, carry out certain lab tests, and the patient has to sign an informed consent form, and the surgery date and time will be scheduled.
The procedure is performed under general anesthesia, local anesthesia, and a sedative.
Preparation of the eye to be operated on:
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Draping the face area around the eye.
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To keep the eyelids open, a speculum is put on them.
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Some lubricant is used to prevent the eye from drying.
In the case of children, a metal ring is stitched to the sclera, which will support the sclera during the procedure).
What Are the Different Techniques Used in Corneal Transplantation?
The different types of corneal transplantation include -
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Penetrating Keratoplasty - Penetrating Keratoplasty is a type of corneal transplantation in which the donor and recipient cornea can be removed in a circular disc using a surgical cutting device named trephine, later operated at the site should be sutured. Eye Drops are placed, the eye is patched, and the patient is taken to a recovery area. The area grafted depends on the extent of the disease process to be addressed.
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Anterior Lamellar Keratoplasty - Another corneal operation consists of two different methods. Removing damage issues from the frontal corneal layers such as epithelium and stroma. The stroma's deep layer should leave the endothelial layer's back.
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Artificial Keratoplasty - Original keratoplasty is not available in some cases, but there is an option for artificial keratoplasty. This procedure is known as keratoprosthesis.
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Endothelial Keratoplasty - Endothelial keratoplasty is a surgical corneal operation where the diseased part can be removed from the back part, especially the cornea's inner cellular layer(posterior stroma). It is a relatively new procedure that has revolutionized the treatment of disorders of the cornea's innermost layer because it uses less or no sutures, and the healing period is comparatively lesser.
What Are the Possible Complications Associated With Corneal Transplantation?
Even though corneal transplantation is a surgical process, it is still considered the safest procedure. Rejection occurs in roughly one out of every ten transplants when the body's immune system assaults the donor tissue. Most of the time, eye drops can be used to reverse it. Descemet stripping endothelial keratoplasty (DSEK) and particularly Descemet membrane endothelial keratoplasty (DMEK) have a substantially lower risk of rejection since very little donor tissue is utilized in these treatments.
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Bleedings.
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Swelling of the cornea.
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Cataract.
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Detached retinal infections.
What Are the Advancements in Corneal Transplantation?
The advancements in corneal transplantation include -
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High-Speed Lasers - High-speed lasers can replace high-speed laser blades to make surgical incisions more precise. These incisions allow the cornea to heal more quickly.
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Stem Cells -The bioengineering technique uses stem cells to create corneas or parts of corneas that can be transplanted into the eyes. These Corneal stem cells are removed from the healthy cornea of a healthy patient. They are collected using laboratory techniques, and five to ten layers of cells are created that can be patched into a patient's eye. The injured corneal tissue has been removed, and the stem cells are implanted.
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Artificial Cornea - Artificial corneas are laboratory constructions, either with or without the support of biological material, and are designed primarily to perform the same functions as the natural human cornea. A normal donor cornea transplant would not be successful in difficult and risky situations. In such a situation, doctors may recommend artificial cornea, which helps to ensure non-toxic, sterile goods with high stability. Furthermore, artificial corneas prevent viral invasion and immunological rejection.
What Is the Prognosis of Corneal Transplantation?
The prognosis of corneal transplantation is very good, as chances of long-term transplant success are
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Keratoconus, traumatic corneal scars, early bullous keratopathy - less than 90 percent.
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Advanced bullous keratopathy or inactive viral keratitis - 80 to 90 percent.
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Chemical or Radiation injury - 0 to 50 percent.
Conclusion
Most people with a cornea transplant get at least part of their vision restored, but each situation is different. It could take a few weeks and up to a year for the vision to improve fully. The eyesight might get worse before it gets better. Individuals suffering from corneal problems or any eye symptoms should get their eyes checked regularly to prevent worsening symptoms and long-term complications.
