Author Insights: Live Corneal Tissue Donation Offers Opportunities and Benefits for Patients and Donors

• Dr Fereshteh Azad, MD, MSc from the Kresge Eye Institute discusses how increased awareness about donation of live corneal tissue could lead to increased availability of much-needed donations as well as psychological benefits for patient-donors dealing with their own illness.

Fereshteh Azad: Hi. My name is Fereshteh Azad. I'm one of the ophthalmology residents at Kresge Eye Institute right now. Previously, I was affiliated with Spectrum Health in Michigan, Grand Rapids.

Prompt 1: What portions of the eye can be donated for transplantation?

Fereshteh Azad: When we think about eye donations and eye transplantations, one might think about the whole eye, but what we usually refer to is the cornea. Before we get into that, I really do want to talk about how we came up with the project, because it's an interesting, actually, start to our project. I was working with Dr. Marchese at Spectrum Health in plastic surgery program, and also Dr. Wan and O'Toole in the ENT department at Spectrum Health.

And we had a patient that came in that was complaining of diplopia, had this maxillary pain and was found to have a maxillary mass in the left side that was extending into the orbit and requiring orbital exoneration. He was very devastated with the prognosis and the diagnosis itself, and he wanted to see if he could offer donating his cornea. And we started looking into if there are any options for a live donation of the cornea and the whole project started.

When we think about cornea, we think about this very surface of the eye, which looks like a dome shaped area, and it's super clear. It helps with particles and germs not getting into the eye. It helps with damaging UV light. It helps with refracting that light and focusing and get into the eye with the help of the lens.

And corneal transplant itself is called keratoplasty and there are different types of corneal transplants based on what layer of the eye is involved as there is five layers to the cornea. Corneal transplants are actually very successful. We do them all the time. There's been usually more around 70,000 corneal transplants every year in the US that's been done. It's secondly most common after blood donation. As it's a very successful procedure and it's commonly done.

And there are certain diseases that make patients needing the transplant itself in the first place. A couple of the... Just to get a little bit of idea or background about what portions can be transferred and going back to your question. Patients who had had previous trauma to the eye that cause scarring to the cornea and damaging the vision obviously. Or any sort of infections from viruses and bacteria and fungi, or even parasites. If there's been any previous eye surgeries that cause damage to the eye.

Some patients have a different shape of the corneas. Instead of having that dome shape that I was mentioning, they have a cone shape that's called keratoconus. Some patients have endothelial dystrophies like Fuchs' dystrophy. Those are one of the most commonly performed surgeries for these types of patients that have corneal transplant.

Regardless of what type of transplant you require and all these transplants come from a diseased donor. And there hasn't been any cases of live donation. Going back to your question though, in terms of what portions. We just discussed, the corneal transplantation portion of it, there are other parts of the eye that are donated too.

We actually use human placenta, which is donated after childbirth. And there's an innermost layer of it. That's called the amniotic membrane and it's basically a healing bandage. We use it for covering the sclera on conjunctiva to regenerate surface tissue when patients have problems with that.

There's also eyelash transplantation, eyelid transplantation, tear ducts transplantation. There's an active area of research right now for retina, where they're looking into some of the diseases that are involved with the macular. For example, macular degeneration of [inaudible 00:04:27] disease. And to see if stem cells can be transplanted to replace the damaged cells, to treat conditions.

Prompt 2: If active tumor is invading the orbit, is there a risk to transferring tumor to the recipient of the cornea?

Fereshteh Azad: Just starting with what our patient, for example, had. Our patient had this maxillary sinus mask extending into the left orbit and destructing the entire left orbital floor. And once we did the biopsy was identified as a squamous cell carcinoma. Fortunately for him, this extension was extraconal, which means that it didn't involve the intraconal aspect of the orbit and the intraocular aspect of it. The intraconal was pretty intact, which means that the cornea was clear and was possible to be harvested for donation.

There are certain criteria as to what is accepted for donation and what is not. Usually in contrast with donation of other organs and tissues, where you have to rule out all the systemic diseases and malignancies. And if the patients do have that, they automatically get disqualified from donation of their tissues. Corneal tissue is a little bit different actually.

If the patient has infection causes like herpes, rabies, hepatitis B, HIV, prion disease, or any sort of CNS infection, those are automatic disqualification factors. There's some exceptions. If the patient has retina blastoma, or lymphoma, or leukemia, or intraconal involvement, then yes, they're automatically contradicted to be donated. But there is a set of accepted criteria by the eye banks that's placed.

And when the technician comes in to do the procurement of the previous event they've done, as a extensive past medical history chart review and blood draw with serological testing and full body examination to make sure that they identify any signs of disease process prior to doing the procurement.

And another interesting thing with corneas, cornea has a different immunological nature. Batching process is really not necessary between donors and recipients. If you want to transfer a liver or a heart, let's say, you have to HLA testing, APO blood group matching. And there's a whole set of serological testing that you have to do. But with cornea, it's such a interesting immunological environment to that, that where we call it the anterior chamber-associated immune deviation, it's like a form of T helper cells where they down regulate the response to antigens and reduce the immune response to transplant tissue and reduce the graft rejection.

And there has actually been multiple studies that looked at this, that looked to see if in transplantation of patients with penetrating keratoplasty, which is a full thickness transplant. If matching the ABO blood group or RH factor was actually changing their risk of graft rejection or survival in five years. And it showed that it didn't make a difference. It wasn't statistically significant.

And there was another study actually, looked at the HLA testing too. If HLA matching, which is a human leukocyte antigen matching that you always do with other types of transplants. They looked at to see if, for corneal transplants, it showed any benefit in matching and it didn't. That means that there's so much potential for increasing corneal tissue procurement. And it's important to consider live donors.