A Full-Thickness Corneal Transplant

Penetrating keratoplasty (PK) is a full-thickness corneal transplant procedure that aims to improve the vision when it is affected by significant conditions of the cornea and spectacles or contact lenses cannot improve the vision to a satisfactory level.

In PK the entire central portion of the abnormal cornea is replaced with a healthy donor cornea. This traditional approach is particularly effective when all layers of the cornea are affected and cannot be treated with partial-thickness, also known as lamellar, procedures.

Indications: When is Penetrating Keratoplasty needed?

The most common reasons for performing penetrating keratoplasty include:

  • Corneal scarring: Deep scars from infections, trauma, or previous surgeries that involve all layers of the cornea.
  • Advanced keratoconus with hydrops: Cases where the cornea has becomes severely thinned and stretched, leading to a break of the inner Descemet’s and endothelial layers.
  • Severe chronic bullous keratopathy: When chronic swelling of the cornea has led to severe corneal scarring.

Corneal perforations: Due to trauma or disease, where urgent full-thickness reconstruction is required to restore the eye’s structure and function.

Recovery and Healing Timeline

Penetrating keratoplasty is a fairly significant eye surgery, and the recovery process is slow and prolonged. Patients may initially experience mild discomfort, but the procedure itself is not painful as it is performed under general anaesthesia. After surgery, the recovery involves managing postoperative inflammation and ensuring the donor cornea integrates properly.

The sutures (stitches) used to secure the new donor tissue often remain in place for 18 to 24 months, as removing them prematurely could destabilise the graft. As a result, it can take a year or longer for vision to improve. Regular follow-up visits are crucial to monitor healing and detect potential complications, such as graft rejection, high pressure or glaucoma, at early stages.

Advantages and Disadvantages of Penetrating Keratoplasty

Advantages:

  1. Broad Applicability: Penetrating keratoplasty can address full-thickness corneal damage, making it an excellent option for severe or complex cases.
  2. Proven Track Record: It is the most established corneal transplantation technique, with decades of clinical success.
  3. Durable Outcomes: In most cases, grafts last for decades, offering a long-term solution for patients.

 

Disadvantages:

  1. Long Recovery Period: With stitches staying in place for up to two years, the healing process is protracted and visual recovery is slow.
  2. Risk of Complications: Higher potential for graft rejection, infection, suture-related problems, astigmatism and glaucoma compared to partial thickness lamellar procedures .

Despite these limitations compared to lamellar surgery, penetrating keratoplasty remains a crucial option for patients with more severe corneal conditions, offering an excellent option for improved vision and quality of life.