Penetrating Keratoplasty

Penetrating Keratoplasty (PKP): Complete Corneal Transplant

Penetrating keratoplasty (PKP) is a surgical procedure in which the entire corneal layer (epithelium, stroma, and endothelium) is replaced with healthy donor tissue. It is an option for advanced cases of keratoconus, corneal scarring, severe infections, or endothelial dystrophies.

Indications for Penetrating Keratoplasty

It is considered when other therapies have failed:

Advanced keratoconus (with scarring or an extremely thin cornea).

Deep corneal scarring (due to infections such as ocular herpes or trauma).

Irreversible corneal edema (endothelial failure, as in Fuchs' dystrophy).

Corneal opacities that impair useful vision.

Surgical Technique

Anesthesia: General or local (depending on the case).

Corneal Button Extraction: A trephine is used to cut and remove the damaged cornea.

Graft Suturing: The donor cornea is secured with 10-0 nylon sutures (16-24 stitches).

Initial Recovery: 24-48 hours with a protective patch.

Postoperative and Follow-up

First week: Use of topical antibiotics and corticosteroids.

First month: Monitoring for possible rejection, monitoring for primary failure.

4-12 months: Progressive removal of sutures.

Visual acuity: Gradual improvement (may take 1-2 years to stabilize).

Graft rejection: 10-20% risk (requires urgent treatment with immunosuppressants).

Advantages

✅ Solution for severely damaged corneas.

✅ Restores vision in complex cases.

✅ Widely available technique.

Disadvantages

❌ High risk of rejection compared to lameral corneal transplants

❌ Slow recovery (up to 2 years).

❌ High post-surgical astigmatism.

Results and Prognosis

Anatomical success: >90% at 1 year.

Useful visual acuity: 20/40 or better in 60-70% of cases.

Complications:

Rejection (signs: red eye, pain, blurred vision).

Infection.

Irregular astigmatism (requires rigid contact lenses or refractive surgery).

Post-Penetrating Keratoplasty Recommendations

Use protective eyewear to avoid trauma.

Close follow-up with an ophthalmologist (every 3-6 months).

Avoid contact sports until approved by the surgeon.

When Should Penetrating Keratoplasty Be Considered?

When keratoconus is intolerant of contact lenses and has central scarring.

If there is painful corneal edema (endothelial decompensation).

Penetrating keratoplasty accounts for 30% of corneal transplants worldwide.

Five-year graft survival is 70-80%.

Post-PKP astigmatism can be corrected with selective sutures or laser.

Many patients will require rigid/scleral contact lenses after PKP.