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A New Window of the Eye: The Corneal Transplant

The cornea is a transparent, dome-shaped tissue that covers the front part of the eye. There are five layers to the cornea, all of which play an important role in vision, and the protection and function of the eye.

The cornea and the tears on it form the main refractive surface of the eye, with a vital role of focusing light and images onto the retina, enabling clear vision. However, certain corneal diseases or corneal damage can lead to its opacification and the need for surgical intervention by corneal transplantation. In such cases, a corneal transplant becomes a viable option.

The following terms all refer to corneal transplantation surgery, taking donor tissue in the form of a donor cornea and replacing the person’s diseased opaque cornea with a clear new window of the eye:

  • Corneal graft
  • Corneal grafting
  • Corneal transplantation
  • Corneal transplant
  • Full thickness keratoplasty

Corneal Diseases requiring a Corneal Transplant:

  1. Corneal Scarring: Scarring and severely reduced vision can occur due to infections, such as keratitis, chemical burn, or physical trauma to the front window of the eye. Severe corneal scarring causes visual impairment, is the most frequent indication for a corneal transplant.
  2. Keratoconus: This condition in young adults involves a progressive thinning and bulging of the cornea, leading to severely distorted vision if left untreated. In advanced keratoconus, a corneal transplant may be required to restore vision.
  3. Fuchs’ Corneal Endothelial Dystrophy: This inherited disorder affects the endothelial layer of the cornea, leading to corneal swelling, blurred vision, and eye discomfort. There are five layers of the corneal, epithelim at the front and endothelium at the back of the cornea. An endothelial layer corneal transplant can alleviate the troublesome symptoms and reduced vision of Fuchs´Corneal Endothelial Dystrophy.
  4. Corneal Degeneration: Corneal dystrophies or certain systemic diseases can cause corneal degeneration, leading to visual impairment. Corneal transplant can improve vision in these cases.

Symptoms indicating the need for a Corneal Transplant

  1. Severe Blurred Vision: When the cornea becomes scarred or damaged, it can result in untreatable blurred or hazy vision.
  2. Corneal Opacity: An chronically opaque or cloudy appearance of the cornea is a clear indication of corneal damage or disease.
  3. Visual Distortion: Conditions like keratoconus can cause astigmatism, resulting in distorted or irregularly shaped vision which if advanced is not treatable by contact lens wear or corneal cross linking treatment.
  4. Sensitivity to Light: Corneal problems may lead to increased discomfort with severe sensitivity to light and glare.
  5. Eye Pain or Discomfort: Conditions like keratitis or corneal ulcers can cause persistent eye pain or a foreign body sensation.

Corneal Surgery Options

  1. Full-Thickness Corneal Transplant (Penetrating Keratoplasty): In this procedure, the entire thickness of the cornea is replaced with a donor cornea. It is typically performed for conditions like corneal scarring following severe corneal infection or traumas.
  2. Partial-Thickness Corneal Transplant (Deep Anterior Lamellar Keratoplasty): This technique involves replacing the outer layers of the cornea while retaining the patient’s healthy innermost layer (endothelium). It is often performed for conditions like keratoconus or corneal dystrophies.
  3. Endothelial Keratoplasty: In this procedure, only the damaged endothelial layer of the cornea is replaced with a donor tissue. It is commonly performed for conditions like Fuchs’ endothelial dystrophy.
  4. Amniotic Membrane Transplantation: In certain cases, amniotic membrane obtained from the placenta can be used to promote corneal healing and reduce inflammation. This technique is often employed for severe ocular surface disorders.

Procedure overview

What happens at surgery: The donor tissue must be reserved from the corneal donor bank. The donor cornea is a human donor tissue. The diseased cornea is surgically removed, then the donor cornea or full thickness donor corneal transplant, is immediately and delicately sutured into place under microscopic control. This is called eye or ocular microsurgery. Only highly trained Corneal Ophthalmic Surgeons do corneal transplants.

Post-Surgical Care and Outlook: After corneal transplantation, patients are typically prescribed medications, including eye drops, to prevent infection, reduce immune rejection of the corneal transplant and promote healing.

Regular follow-up: visits with the corneal surgeon (specialist ophthalmologist) are crucial to monitor progress and ensure proper integration of the transplanted corneal donor tissue. While corneal transplants have a high success rate, full visual recovery may take several months. The delicate micro suture is left in up to a year, and is not usually felt at all by the corneal transplant patient.

Corneal transplantation

This is a most valuable surgical option for saving or restoring sight in individuals with corneal damage or a diseased cornea which cannot be adequately managed through non-surgical means.

Understanding the causes and symptoms associated with corneal transplants is essential in seeking timely medical intervention.

With advancements in ocular microsurgical techniques and post-operative care, corneal transplantation continues to offer hope for improved vision and enhanced quality of life for those in need.

Who does Corneal Transplantation?

The highly trained Corneal Ophthalmic Surgeon, Mr Sajjad Ahmad at Clinica London will assess the need for corneal transplant and advise on the best surgical option. He is a specialist in external eye, refractive, cornea and eye anterior segment micro-surgery

Ten Corneal Transplant Facts

Here are ten interesting facts about corneal grafts/transplants:

1. Human corneal transplants have been performed for over a century: The first successful corneal transplant was performed in 1905 by Dr. Eduard Zirm in Czechoslovakia.

2. The cornea is the clear, dome-shaped front part of the eye that covers the iris and pupil. It has 5 corneal layers and contains many fine delicate almost invisible but highly sensitive corneal nerves. It has no blood vessels, hence maintains its transparency. It plays a crucial role in focusing light onto the retina.

3. Corneal transplantation can restore vision: When the cornea becomes damaged or diseased, it can lead to vision loss or impairment. Corneal transplantation can help improve vision and alleviate symptoms such as blurry vision, pain, and sensitivity to light.

4. There are different types of corneal transplants: The most common type is called a full thickness penetrating keratoplasty, where the full thickness of the cornea is replaced by a fresh donor corneal transplant. Another type is called lamellar keratoplasty, which involves replacing only specific layers of the cornea.

5. Corneal transplantation has a high success rate: The success rate of corneal transplants is around 90% of transplants functioning well after one year. However, individual results may vary depending on various factors such as the patient’s overall eye health and the specific condition being treated.

6. Corneal donor tissue is usually obtained from deceased donors: The corneas used in grafting procedures are typically obtained from individuals who have recently passed away but had donated their corneas for transplantation. These donations are crucial in providing corneas for patients in need. The corneas are all from the human corneal bank and have been screened for communicable diseases.

7. The immune response of the host cornea to the new adjacent donor cornea is a key consideration: The success of corneal transplantation is partially attributed to the unique immune privilege of the cornea. The cornea has low immunogenicity, meaning it is less likely to be rejected by the recipient’s immune system compared to other types of tissue transplants. However, some patients may still require long-term immunosuppressive medications in the form of eye drops to prevent rejection.

8. Corneal transplant rejection is possible: Although corneal transplants have a relatively low rejection rate compared to other organ transplants, there is still a risk of rejection. Signs of rejection include redness, pain, decreased vision, hazy donor cornea, vascularised donor cornea and sensitivity to light. Timely detection and treatment can improve the chances of saving the graft.

9. Advancements in surgical techniques: Over the years, advancements in surgical techniques, such as the use of femtosecond laser technology and selective tissue transplantation, have made corneal transplantation more precise and effective.

10. Worldwide demand for corneal transplants: Corneal transplantation is one of the most common types of organ transplantations performed globally. However, the demand for corneal tissue exceeds the available supply in many countries, highlighting the need for increased awareness about eye donation. The collection, screening and storage of donor corneal tissue is highly regulated to ensure maximum safety for the corneal recipient patient.

Check other eye treatments, and book an appointment to evaluate your conditions or do regular check-ups.

Mr Sajjad Ahmad

Mr Sajjad Ahmad

Consultant Ophthalmic Surgeon
Cornea & External Eye Diseases, Cataract, Keratoconus & Refractive Surgery Specialist

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