Question

Discuss the indications and complications of therapeutic penetrating keratoplasty.

Hint:

Close monitoring for complications like graft rejection and infection after therapeutic PK is essential to ensure the success of the surgery and maintain visual outcomes.

Answer 1

Therapeutic penetrating keratoplasty (PK) is a surgical procedure in which the entire thickness of the cornea is replaced with a donor graft to treat corneal diseases that are causing vision impairment or threatening the integrity of the eye.

Step 1: Indications for Therapeutic Penetrating Keratoplasty:
1. Corneal Scarring: PK is indicated when the cornea is scarred due to infections, trauma, or degenerative diseases. Scarring can significantly reduce vision and compromise the integrity of the eye.
2. Keratoconus: A progressive thinning and bulging of the cornea often requiring PK when other treatments like contact lenses fail.
3. Infectious Keratitis: Therapeutic PK is indicated for patients with severe bacterial, fungal, or viral keratitis, where the infection is unresponsive to medical treatment, and there is a risk of corneal perforation.
4. Corneal Dystrophies: Conditions like endothelial dystrophy, where the corneal endothelial cells fail, can lead to corneal edema, requiring PK to restore vision.
5. Corneal Ulcers and Perforation: PK is needed in cases where corneal ulcers lead to perforation or imminent perforation, particularly in the presence of infectious or inflammatory conditions.

Step 2: Complications of Therapeutic Penetrating Keratoplasty:
1. Graft Rejection: One of the most significant complications of PK is graft rejection, where the recipient's immune system attacks the donor tissue. This can lead to graft failure and requires immediate medical intervention.
2. Infection: The corneal transplant can become infected post-operatively, leading to endophthalmitis, especially if there is poor wound healing or postoperative care.
3. Astigmatism: PK can lead to irregular corneal shape, resulting in postoperative astigmatism, which may require corrective lenses or additional surgery.
4. Glaucoma: The surgery can increase intraocular pressure due to changes in the anterior chamber and potential damage to the trabecular meshwork.
5. Corneal Graft Failure: This occurs when the transplanted cornea fails to integrate properly or if there is delayed epithelial healing, leading to the loss of the graft.