Keratoplasty can be Penetrating or Lamellar.
Penetrating Keratoplasty
Penetrating Keratoplasty consists of replacing the entire thickness of the diseased cornea with a cornea of a deceased donor. Therefore, a central button with a diameter varying between 7 and 8 mm is removed, leaving a corneal ring of 1 to 3 mm in the receiver´s eye to which the donor button is sutured, with an equivalent diameter.
Because the cornea is a bloodless tissue, its transplantation does not carry as many risks of rejection as in other tissues or organs. Thus, the percentage of rejection cases is low, although it varies according to the pathology that led to the transplant. The administration of systemic immunosuppressive medicinal products is generally not necessary.
Although the recovery of vision in this type of transplant takes few months, the result is usually satisfactory and long-lasting, after correction of residual astigmatism.
Lamellar Keratoplasty
Lamellar Keratoplasty can be of two types:
Posterior or Endothelial Lamellar Keratoplasty (DSAEK, DMEK)
This procedure allows, in cases where the corneal disease is limited to the deeper cellular layer of the endothelium, (such as Fuchs Endothelial Dystrophy and Endothelial Decompensation after cataract surgery), to transplant only the diseased layer through a small incision.
The recovery of visual acuity is much faster, weeks instead of months, than the traditional penetrating transplants.
Deep Anterior Lamellar Keratoplasty (DALK)
In reverse situations where the endothelium is healthy, and the cornea is deformed (keratoconus, ectasia), or opacified (maculae, leucoma), there will be every advantage in preserving it by replacing only the altered layers.
This technique can be assisted by Femtosecond Laser.
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