Your ophthalmologist has suggested a corneal transplant.
What is the cornea?
The cornea is the “window” through which light enters the eye. It’s a tissue essentially made up of collagen, located at the front of the eye in contact with the eyelids, tears and air. The cornea’s role is to transmit light into the eye thanks to its transparency, to focus incident light rays towards the retina thanks to its curvature, and to act as a barrier to the environment thanks to its resistance and elasticity.
What pathologies affect the cornea?
A number of pathologies can cause the transparency or curvature of the cornea, leading to a permanent drop in visual acuity:
- Prolonged corneal edema (Cornea Guttata, Fuchs endothelial dystrophy),
- Infection scars (abscesses, herpes),
- Scars
from trauma (wounds, foreign bodies, burns, surgery) - Hereditary opacifying diseases (corneal grid dystrophies, polymorphic dystrophies, etc.)
- Exaggerated deformation of the cornea (Keratoconus)
When should a corneal transplant be performed?
Your ophthalmologist will suggest a transplant if all other non-surgical treatment options are insufficient to correct defects in corneal transparency or curvature. These options may include glasses, contact lenses, eye drops, medications, intracorneal rings or lasers.
What is a corneal transplant?
Corneal transplantation is a surgical operation in which a recipient’s defective cornea is replaced by a healthy cornea taken from a deceased patient (graft on). The transplanted patient must not have refused organ donation during his or her lifetime. Corneal donation is free of charge, and the anonymity of both donor and recipient is guaranteed. The corneal banks and the Agence de Biomédecine are responsible for the management of transplants and graft quality control. Patients waiting for a transplant are registered on a national registry, and the waiting period for a transplant can be up to 6 months.
What are the different types of corneal transplants?
In the vast majority of cases, the corneal graft is partial, i.e. only part of the cornea is replaced. This is known as lamellar keratoplasty, and there are 2 types:
- Posterior lamellar or endothelial keratoplasty involves replacing the thin layer of cells lining the deep posterior surface of the cornea, in contact with the aqueous humor inside the eye. This thin layer, around 16 microns thick, is essentially made up of so-called endothelial cells, whose role is to maintain the cornea’s normal hydration. Posterior grafting is indicated when the endothelial cells become deficient and chronic edema with corneal opacification develops. This condition is known as Cornea Guttata or Fuchs’ Endothelial Dystrophy.
- Anterior lamellar stromal keratoplasty involves replacing only the front, transparent part of the cornea. This thick layer, around 500 microns thick and made up mainly of collagen, is called the corneal stroma. This type of graft is indicated for all other corneal pathologies responsible for opacities or disorders of corneal curvature (infections, trauma, keratoconus, etc.).
Finally, in certain cases of very advanced pathology, or when lamellar grafts fail, your surgeon may propose replacing your entire cornea. This is called
Total or transfixing keratoplasty.
How is surgery performed?
In most cases, the ophthalmology team will admit you to Ambulatory Surgery for a half-day stay. You must have stopped eating, drinking and smoking at least 4 hours before hospitalization. The procedure is usually performed under local anaesthetic, and usually lasts less than an hour.
What happens after the operation?
The immediate post-operative period may be marked by tearing, redness, stinging and grainy sensations, which generally subside within a week. Improvement in visual acuity comes later, after several weeks. It is essential to follow your eye drop treatment carefully, avoid rubbing your eyes, and avoid activities that could cause eye trauma. You will be given several post-operative appointments in the following months.