What is a Corneal Transplant?
Corneal transplant surgery is the most commonly performed and most successful organ transplant procedure, and it does not require systemic immunosuppression. Antirejection drops (topical steroids) are needed, sometimes for life.
The cornea is the clear front structure of the eye. It must be transparent and smooth to provide clear vision. Conditions that produce scarring or swelling of the cornea cause reduction of vision and glare.
There are five layers to the cornea: The epithelium which lies over Bowman’s membrane, the stroma which is made of layers of tightly packed collagen, and Descemet membrane which is coated with endothelial cells.
Conditions or Corneal Diseases That May Require a Transplant
Keratoconus: A deformed cone shaped cornea
Fuchs’ Dystrophy: An inherited disease of the lining of the cornea (endothelium)
Corneal Scars: Resulting from eye infections or injuries
Corneal Damage: From previous eye surgery
Types of Corneal Transplants
Penetrating Keratoplasty (PKP) or full thickness corneal transplant where all layers of the cornea are replaced with a clear healthy donor tissue which is secured in place with multiple sutures. A PKP requires a full year to heal. Attaining maximal visual recovery may still require a contact lens if the surface of the new cornea is irregular. Indefinite protection from eye injury is mandatory after a PKP.
Partial Thickness Corneal Transplant (DALK), also Known as Deep Anterior Lamellar Keratoplasty, replaces the front and middle section of the cornea while preserving the lining. It is an alternative to a full thickness graft. The advantages of DALK included reduced rejection rate, earlier return to unrestricted physical activity and shorter healing time. Reduced dependence on topical steroids (anti-rejection drops) after DALK creates less risk for steroid induces glaucoma and cataracts.
Endothelial Keratoplasty is a partial thickness transplant that replaces the damage innermost layer of the cornea (endothelium). There are two types of endothelial keratoplasty:
DSEK: Descemet Stripping Endothelial Keratoplasty
DMEK: Descemet Membrane Endothelial Keratoplasty
The type of endothelial keratoplasty procedure chosen by the surgeon depends on the corneal condition and anatomy.
The difference between a DSEK and DMEK is in the thickness of tissue transplanted and associated technical difficulty.
The advantages of endothelial keratoplasty:
- Faster visual recovery
- The eye is less susceptible to damage if injured
- Less astigmatism and minimal change in eyeglasses prescription
- Suture related problems are reduced or eliminated
- Fewer restrictions on physical activity after surgery
DWEK (Descemet without Endothelial Keratoplasty), also known as DSO (Descemet Stripping Only), is a procedure where a small area of the lining of the cornea is removed to allow the patient’s own cells to regenerate without transplanting a donor tissue. It is offered to select Fuchs’ dystrophy patients.
Contact us to schedule a consultation with the experienced cornea transplant surgeons at Washington Eye Physicians and Surgeons.
Image of cornea © 2021 American Academy of Ophthalmology
