Could 3-D Retina Transplants Put a Stop to Degenerative Blindness?

More than two million Americans suffer from age-related macular degeneration (AMD). While AMD does not result in total blindness, it is the leading cause of vision loss among Americans age 50 and above, and it causes sufferers to slowly lose central vision and interferes with an individual’s ability to drive, read, write, recognize faces, and more. There is no cure for AMD, although doctors can prescribe treatments in an effort to slow its progression.

AMD is only one of several degenerative eye conditions that lead to vision loss for which there has been no cure since it is caused by the actual decay of structures within the eye. However, this may soon change thanks to a groundbreaking advance in medicine: the development of transplantable 3-D retinas.

A team of researchers at California-based AIVITA Biomedical led by CEO Hans Keirstead, PhD have successfully used human embryonic stem cells (hESCs) to develop a 3-D “retinal organoid” made of laminated retinal progenitor cells and retinal pigment epithelium (RPE). In preclinical studies, the researchers showed that, when injected into the eye, the organoid was able to form synaptic connections with existing tissue and thus restore vision.

“The cause for hope for transplanting a 3-D retina has never been greater,” Keirstead told Modern Retina. “We have been on a relatively long journey, but are now at a point where we will be walking along a well-articulated path that will lead us to the beginning of our first in-human study.”

Keirstead, who suspects that a clinical research phase for the 3-D retinas may be as soon as two years away, explained that AIVITA’s target population is patients with degenerative disease of the outer retina, like AMD or retinitis pigmentosa. The 3-D retinas can be transplanted in the patient’s eye to replace the diseased or non-functional photoreceptors and RPE and establish new, functional connections with the inner retina and restore lost vision.

Of course, there are still a number of challenges ahead of the researchers, and the retinas are still years away from becoming commercially available for patients. But the possibility that 3-D retinas could be viable for use in patients opens the door for millions of patients, potentially, to get their sight back.

Corneal Transplant Surgery: What You Should Know

hargrave eye centerYou may need a cornea transplant if your cornea no longer lets light enter your eye properly because of scarring or disease.  The first cornea transplant was performed in 1905 by Eduard Zirm (Olomouc Eye Clinic, now Czech Republic), making it one of the first types of transplant surgery successfully performed.  

According to the Mayo Clinic, a cornea transplant, also called keratoplasty, is a surgical procedure to replace part of your cornea with corneal tissue from a donor. Your cornea is the transparent, dome-shaped surface of your eye that accounts for a large part of your eye’s focusing power.  A cornea transplant can restore vision, reduce pain and improve the appearance of a damaged or diseased cornea.  Most cornea transplant procedures are successful. But cornea transplant carries a small risk of complications, such as rejection of the donor cornea.

Types of cornea transplants include:

  • Penetrating (full thickness) cornea transplant. This involves transplanting all the layers of the cornea from the donor.
  • Lamellar cornea transplant. During this procedure, the surgeon only replaces some of the layers of the cornea with the transplant.

ocular healthExperts know more about the long-term success rates of penetrating cornea transplants, which use all the layers of the cornea.  Success rates are also affected by the problem that needed to be fixed with the transplant. For example, research from WebMD has found that the new cornea lasts for at least 10 years in:

  • 89% of people with keratoconus
  • 73% of people with Fuchs’ dystrophy
  • 60% to 70% of people with corneal scarring

The cornea tends to heal slowly. To help protect your eye in the days after the surgery, your doctor may ask you to wear a protective shield over it.  You will need to use eyedrops for several months after the transplant which can then be reduced to one drop a day or discontinued. The stitches may remain in your eye for months or years. Your eye doctor can remove them in a simple procedure during an office visit.  Your vision may improve slowly after the surgery. It’s important to avoid any possible trauma to your eye, such as from sports. This can damage your new cornea. You should report new irritation or any decrease in vision to your corneal surgeon. These may be signs that your body is rejecting the donor cornea. Most transplant rejections are fully reversible with steroid eyedrops if detected early enough.  Rejection may even occur years after the surgery. If you notice any of these signs that last for more than six hours, call your eye doctor promptly. The doctor can give you medicine that can help prevent as well as treat rejection.

Eye donors are screened to eliminate those with diseases that may be transferred to you via the donor cornea. The donor’s general and eye medical history are reviewed, and blood tests are performed for hepatitis and AIDS. AIDS has never been transmitted via corneal transplant, but it is tested as a precaution. While none of these tests are infallible, there is only a remote chance of transmitting disease via corneal transplantation.