Cornea Transplant Surgery

What is the cornea?

The cornea is a clear window at the front of the eye.  It is very important for the cornea to remain clear so that the eye can function normally and good vision can be experienced by the patient.  There are many diseases that can potentially affect the cornea but essentially these diseases either affect the shape of the cornea, which causes blurred vision, or they affect the clarity of the cornea, which also causes blurred vision.


Conditions that affect the shape of the cornea

Conditions that affect the shape of the cornea are broadly grouped as ectatic conditions.  This is where the cornea rather than assuming a nice round shape starts to develop an egg shape to it.  Conditions that can give rise to this problem are keratoconus, pellucid marginal corneal degeneration and less commonly keratoglobus.  On rare occasions, patients who have undergone laser refractive surgery can develop a form of this problem called post LASIK ectasia.


Keratoconus, pellucid marginal degeneration and keratoglobus

In these conditions, the corneal shape becomes irregular and more egg shaped.  This can give rise to blurred vision.  Often glasses can be used to help improve the vision.  In some patients however, the condition is progressive and in these cases, we apply a treatment called collagen cross-linking.  Collagen cross-linking is very effective at halting the progression of these diseases.  In some patients the irregular shape of the cornea is such that it cannot be managed with glasses alone and in some cases we need to use a hard contact lens which is prescribed through an optometrist or on some occasions we need to perform surgery.

In milder cases of keratoconus, pellucid degeneration and keratoglobus, we can perform a procedure called intrastromal ring segment implantation.  If the corneal condition is very severe, then we perform a corneal transplant procedure.  The corneal transplant procedure is performed as a deep anterior lamellar keratoplasty (DALK) or on some occasions penetrating keratoplasty (PK).

Conditions that can affect the clarity of the cornea

The clarity of the cornea can be affected from either scars or swelling of the cornea.  Scars often result from previous trauma or infection.  In some patients, they can develop corneal swelling due to failure of the internal pump mechanism of the cornea (corneal endothelial cells).  Scars, if severe, can be treated by corneal transplantation.

If there is a problem in the cornea due to swelling, which is typically seen in a condition called Fuchs’ corneal dystrophy or on occasion following intraocular surgery or trauma, then a cornea transplant procedure can be performed.  In these cases, an endothelial keratoplasty is performed where the diseased corneal endothelium is transplanted and the rest of the cornea is left undisturbed.  This gives rise to a quicker postoperative recovery of vision and a potentially safer operation because this is performed through small incisions.


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Hunter Eye Hospital