Types of corneal transplant
There are full and partial thickness corneal transplants. The type of transplant of choice depends on the layer that is affected by disease.
Corneal diseases which affect the entire thickness of the cornea, a full thickness corneal transplant, also known as penetrating keratoplasty, removes the entire thickness of the cornea and replaces it with a healthy donor cornea.
There are various partial thickness corneal transplants such as Anterior lamellar keratoplasty (ALK) and deep anterior lamellar keratoplasty (DALK). When the disease of the cornea affects the front layers of the cornea, partial thickness transplant is the surgery of choice whereby only the front layers of the cornea is removed and is replaced with the donor cornea, leaving the back layers of the patient’s own cornea intact.
When the cells at the back layer of the cornea are not functioning, leading to a swollen and non-transparent cornea, they are removed and substituted with healthy donor cells which rest on the Descemet’s membrane. The patient’s own front layers of the cornea are left in situ.
The two types of this transplant are called Descemet stripping automated endothelial keratoplasty (DSAEK) and Descemet’s membrane endothelial keratoplasty (DMEK).
A corneal transplant presents an opportunity for better vision in diseases of the cornea not amenable to glasses, rigid gas-permeable contact lens or medications.