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.
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:
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:
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.
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