Corneal Graft Rejection

Corneal Graft Rejection: Symptoms, Signs, Prevention, and Graft Survival

Corneal rejection is an immunological complication that can occur after a corneal transplant (penetrating keratoplasty (PKP) or lamellar keratoplasty (DALK). It is the leading cause of graft failure and requires early detection and urgent treatment.

Symptoms and Signs of Corneal Rejection

Rejection can occur days, months, or even years after the transplant. Patients should be alert for:

Subjective Symptoms (what the patient feels)

✔ Red eye (conjunctival hyperemia).

✔ Eye pain (mild to severe).

✔ Sudden blurred vision.

✔ Photophobia (sensitivity to light).

✔ Excessive tearing.

Clinical Signs (what the ophthalmologist sees)

🔹 Inflammatory infiltrates in the graft (lymphocytes attacking the tissue).

🔹 Corneal edema (thickening and loss of transparency).

🔹 Keratic precipitates (deposits of immune cells on the endothelium).

🔹 Corneal neovascularization (growth of blood vessels into the graft).

🔹 Endothelial rejection line (visible with a slit lamp).

How to Prevent Corneal Rejection?

Prevention is key, especially in the first 2 years post-transplant:

Use of topical corticosteroids (prednisolone, dexamethasone):

High doses initially, gradually tapering.

Some patients require long-term therapy (years).

Systemic immunosuppressants (in high-risk cases):

Cyclosporine, tacrolimus.

Avoid risk factors:

Ocular trauma (contact sports).

Untreated infections (ocular herpes).

Loose or infected sutures.

Close follow-up:

Periodic slit-lamp examinations and endothelial microscopy.

Corneal Graft Survival

The transplant success rate depends on multiple factors:

5-year survival

PKP (Penetrating Keratoplasty): 70-80%

Lamellar Keratoplasty: 85-90% (lower rejection due to preserving the patient's endothelium)

Younger patients: Higher risk of rejection (more active immune system)

Neovascularized corneas: Reduced survival (50-60%)

When is a graft considered "successful"?

Anatomical survival: The graft remains transparent.

Functional survival: The patient achieves useful vision (20/40 or better).

What to Do if Rejection Is Suspected?

See an ophthalmologist urgently (rejection is reversible if treated promptly).

Increase the frequency of corticosteroid drops (e.g., prednisolone every hour).

Oral immunosuppressant therapy (in severe cases).

80% of rejections occur in the first year post-transplant.

Lamellar keratoplasties have a lower rejection rate than PKP.

Long-term use of topical corticosteroids reduces the risk of rejection by 50%.