What is a cornea?

The cornea is the eye’s outermost layer. It is the thin, transparent dome-shaped surface of the eye that covers the iris (coloured part of the eye), pupil and anterior chamber. Approximately the size of a one cent piece, the cornea forms the protective covering of the eye and focuses most of the incoming light.

Vision and the cornea – how does the cornea work?

Light first enters the eye, and is bent (refracted) by the cornea, it then becomes focused by the lens, before being projected onto the retina where the stimulation is interpreted by the brain as a visual picture or image.

The cornea acts as the eye’s outermost lens. Just as a camera lens focuses light onto film, the cornea focuses light onto a light-sensitive membrane called the retina. The retina functions much like the film inside the camera, and the iris like the camera shutter.

If the cornea becomes damaged or cloudy through disease, degeneration, infection or injury, the resultant scarring or discoloration causes impaired vision by blocking or distorting light as it enters the eye. Vision becomes dramatically reduced, and in some cases blindness may result. Severe damage of the cornea also impairs the protection of the eye from the drying environment and against infection.

What is a cornea transplant?

A cornea transplant is a micro-surgical procedure to remove all or part of a damaged (injured or diseased) cornea and replace it with healthy donor corneal tissue. A cornea transplant is often referred to as Keratoplasty or a corneal graft. It can be used to improve sight, relieve pain and treat severe infection or damage.

Who would need a cornea transplant?

Adults, children and even babies may need cornea transplants, for a variety of reasons. A transplant may be necessary in the case of cornea failure due to hereditary conditions such as Fuchs’ dystrophy, or Keratoconus (thinning and steep curving of the cornea). A transplant might also be required due to scarring resulting from trauma or injury, ulceration, infection or scarring as a result of previous ophthalmic surgery. Certain ageing processes can also affect the clarity and health of the cornea.

How great is the need for corneas and eye tissue?

Despite many hundreds of corneal graft surgeries taking place each year in South Africa, the need is ever increasing and unfortunately, never satisfied. To date, the use of artificial materials for corneal transplants has been unsuccessful. As a result, patients awaiting corneal transplants depend solely on the gift of tissue donation.

Should a donor elect to donate the complete eye, rather than the cornea alone, the sclera (white part of the eye) may be used in ocular graft procedures related to other types of eye disease.

Is there a time limit after death in which the corneas must be recovered?

Yes , the optimal recovery time limit after death is 12 hours, during which the Eye Bank personnel will need to procure the donated corneal or eye tissue.

How long does it take for the corneas or eye tissue to be procured and will this delay funeral arrangements?

The process of recovering the donated corneal or eye tissue and thereafter ensuring the preservation of the donor’s appearance takes approximately 30 minutes. Arrangements for this tissue recovery do not compromise funeral arrangements and the Eye Bank staff will usually liaise with the funeral home or hospital in this regard.

How soon will the donated corneas be used for transplantation?

A corneal transplant is usually performed 10 days of donation. This is dependent upon the completion of routine testing, the location of the receiving hospital, and the preparation of the selected recipient.

What is the procedure following corneal and scleratissue recovery?

Donated tissue is procured by trained personnel from the Eye Bank. Thereafter, the corneal or eye tissue is carefully stored in preservation media and transported to the Eye Bank where it is placed in a sterile environment within a temperature regulated medical grade walk-in refrigerator. After routine medical grade evaluations to identify infections or imperfections the donated corneal and eye tissue is made available for recipient selection and allocation. The donated tissue is then transported to the requesting recipient hospital in a controlled environment and using tracking procedures to ensure it is safely delivered.

This entire process entails the use of sterile, disposable consumables, professionally trained personnel and the facilities necessary to support resources for the efficient operation of the service. The fee levied covers associated procurement costs and ensures the continued development of the Eye Bank, an essential and community-driven healthcare resource within the Province. Patient recipients of grafts and transplants within State Hospitals receive corneal and eye tissue at the State Hospital’s expense. Private Medical recipients receive corneal and eye tissue which is usually reimbursed by their Medical Scheme.

Will the corneal / eye tissue recipients be informed of the identity oftheir donor?

No. The gift of sight is usually made anonymously. Specific information pertaining to the donor or donor family is not freely available to the recipient. However, the Eye Bank encourages recipients to write a letter of thanks to the donor family, which will then be forwarded on by the personnel. The Human Tissue Act does, however, make mention of an option for the two parties to meet, should both donor and recipient parties agree. In this case a written application must be submitted to the Eye Bank.

Who can qualify to become a cornea or eye tissue donor?

Any person between the ages of 6 and 65 years and even up to 70 years in certain cases, where death is as a result of either natural causes (for example heart diseases, most cancers, strokes) or unnatural circumstances (for example motor vehicle accident injuries, gunshot wounds, stab wounds). Cataracts and poor eyesight do not prevent eye donation, however, previous laser surgery to the eye and infections such as Tuberculosis and HIV Aids as well as Lymphoma and Leukemia are unfortunately contra-indications for donation. The Eye Bank personnel may be required to ask the next-of-kin, as well as the potential donor’s doctor for information on the health status and circumstances surrounding the death of the deceased, in order to determine whether the tissue may be suitable for donation.

Why become a cornea or eye tissue donor?

Sight is essential to the normal daily functioning and holistic life experience of an individual. Whether performing your occupation, caring for children or learning at school the gift of sight is enhanced through vision. Every year, more than 300 people in the Gauteng Province will have their sight preserved or restored through corneal transplantation. In addition to the cornea, the sclera (white part of the eye) can also be donated and used for ocular graft surgery in the treatment of cancer.