The cornea is the clear front window of the eye, and is the most important element for bending light rays to produce a clear focus on the retina at the back of the eye. A healthy, clear cornea is essential for good vision. A diseased, swollen or scarred cornea affects vision by scattering or distorting light and causing glare and blurred vision, and sometimes corneal disease can lead to severe eye pain. In some cases of corneal disease, vision can be improved with specialty contact lenses, by removing scar tissue with surgery, or by surgically improving the shape of the cornea to improve vision. In more advanced cases, a corneal transplant (graft) may be necessary to restore functional vision. This procedure replaces damaged corneal tissue with healthy corneal tissue donated from our local NSW Eye Bank in Sydney. Traditionally, corneal transplant surgery has meant replacing the full thickness of the central cornea with a full thickness corneal transplant (known as a penetrating keratoplasty). Modern corneal transplant surgery involves selectively transplanting only the diseased layers of the cornea (lamellar transplant surgery), which can be either the front layers only, or the back layer only.
There are three main types of corneal transplants:
1) Traditional, full thickness corneal transplant, also known as penetrating keratoplasty (PK)
2) Partial thickness corneal transplant of the front layers, also known as deep anterior lamellar keratoplasty (DALK)
3) Partial thickness corneal transplant of the back layer, also known as endothelial keratoplasty (eg Descemet’s Stripping Automated Endothelial Keratoplasty – DSAEK)
When Do You Need a Cornea Transplant?
If your cornea is damaged due to eye disease or eye injury, it can become swollen, scarred or severely misshapen and distort your vision. A cornea transplant may be necessary if spectacles or specialty contact lenses cannot restore your functional vision or if painful swelling cannot be relieved by medications.
Some of the conditions that may require a corneal transplant to improve vision :-
• Fuchs’ endothelial dystrophy
• Advanced keratoconus with scarring and/or significant thinning, not suitable for other procedures to rehabilitate the vision
• Scarring from infections, such as contact-lens related infections, herpes affecting the eye or fungal infections of the cornea
• Excessive swelling (oedema) of the cornea, such as after complicated cataract surgery
• Chemical burns of the cornea or damage from an eye injury
• Graft rejection following a previous corneal transplant