Can a Blind Person See Again With Eye Transplant?

For a long time, people have been fascinated by the idea of giving sight back to the blind with eye transplants. Now, with big leaps in medicine and technology, we wonder: Can eye transplants really make blind people see again? In this article, we’ll take a close look at eye medicine today, the hurdles we still need to overcome, and the groundbreaking research that might someday bring sight back to those who can’t see. We’ll explore everything from how we’re trying to fix damaged nerves to the latest in bionic eyes and stem cell treatments. Come with us as we explore the exciting possibilities of bringing back sight.

What is Blindness?

Blindness is defined as a significant loss of vision that cannot be corrected with standard visual aids like glasses or contact lenses. It can range from partial vision loss, where limited sight remains, to complete blindness, where there is no perception of light at all. The term is often used more broadly to cover severe visual impairments, and legal definitions of blindness can vary, typically involving criteria such as visual acuity worse than 20/200 in the better eye with corrective lenses, or a very narrow field of vision, less than 20 degrees wide.

Types of Blindness

Partial Blindness: In this condition, some level of vision is still present, often referred to as “low vision.” Individuals with partial blindness may have a significantly reduced visual acuity or a very limited field of vision, but they can still perceive light, shapes, and some degree of detail.

Complete Blindness: This is the absence of any light perception and visual capability. Complete blindness is quite rare and means that an individual cannot see anything, not even light. This level of vision loss results in a total reliance on non-visual senses and skills for navigation and daily activities.

Congenital Blindness: This type of blindness is present at birth or develops shortly after. Causes range from genetic conditions affecting the eyes or optic nerves to developmental issues in the womb or birth defects. People with congenital blindness may have various levels of residual vision, from almost none to relatively light perception or the ability to detect some motion.

Legal Blindness: Defined not by a complete lack of vision but by specific legal standards, typically involving visual acuity and field of vision. A person is considered legally blind if their vision in the better eye, even with the best possible correction, is 20/200 or worse. Alternatively, legal blindness can be determined by a severely restricted field of vision, less than 20 degrees wide, making it hard to perceive surroundings fully.

Nutritional Blindness: This form of vision impairment is caused by a deficiency in vitamin A, which is crucial for maintaining healthy vision, especially in low-light conditions. Prolonged vitamin A deficiency can lead to xerophthalmia, a condition that damages the cornea and can lead to night blindness or more severe visual impairment if not treated. Nutritional blindness highlights the importance of a balanced diet for eye health.

Brief History of Eye Transplantation Attempts

For centuries, scientists and doctors have been captivated by the idea of transplanting eyes, facing many challenges along the way. The quest to make eye transplants possible has grown from just an idea to detailed experiments, showing the progress in medical science and technology. People have thought about moving eyes or eye parts since ancient times. However, it wasn’t until the late 1800s and early 1900s that doctors started trying out corneal transplants, which are simpler than transplanting a whole eye. In 1905, Eduard Zirm successfully completed the first corneal transplant, a big step forward for eye surgery. This achievement paved the way for more complex transplant research.

During the 1900s, researchers tried many times to transplant eyes in animals, but these attempts usually failed. The eye is very complex, and the body often rejects transplanted parts. Thanks to advances in microsurgery and better ways to prevent rejection, recent research has shifted to transplanting specific eye parts, like retinal cells or the RPE, instead of the entire eye.

Challenges in Full Eye Transplantation

Despite these advancements, the prospect of full eye transplantation remains daunting due to several critical challenges:

• Nerve Regeneration: The optic nerve, which links the eye to the brain, needs to regrow and attach correctly. This nerve has over a million fibers, so reconnecting it is very complex. The central nervous system, including the optic nerve, hardly ever regrows after damage.
• Immune Rejection: The eye is usually safe from the body’s immune attacks to protect sensitive vision tissues. But this safety makes transplanting tricky because the body might strongly reject new, foreign tissue. Balancing the immune response to avoid hurting the eye’s function is tricky.
• Eye Complexity: The eye is complex, with parts like the retina, cornea, and lens, each needing to work together perfectly after a transplant. Making sure all these parts work well together after a transplant is a big challenge.

What Parts of the Eye Can Be Transplanted?

1. Corneal Transplants

Corneal transplantation has been a viable and successful treatment for nearly a century. Clear vision relies heavily on the cornea, the eye’s front surface. When the cornea is scarred or swollen due to injury or disease, vision can become blurred or cause glare. In a corneal transplant, a damaged cornea is surgically replaced with a clear donor cornea. Depending on the specific condition of the cornea, there are various types of corneal transplant procedures available, each tailored to address different layers or sections of the cornea.

2. Amniotic Membrane Transplantation (AMT)

This innovative procedure utilizes the amniotic membrane from a donated human placenta after childbirth. The amniotic membrane serves as a therapeutic bandage to promote healing and regeneration of the eye’s surface tissues. This technique can be applied either as a temporary or permanent solution, offering a unique approach to treating conditions affecting the sclera and conjunctiva.

3. Eyelash Transplants

Eyelash transplantation is a surgical procedure aimed at restoring eyelashes that have been lost due to burns, injuries, or medical conditions. This procedure involves transplanting hair follicles to the eyelid to achieve natural-looking eyelash growth.

4. Eyelid and Tear Duct Transplants

The field of eye transplantation is continuously evolving, with ongoing research into the feasibility of transplanting other eye components, such as eyelids and tear ducts. Notably, in July 2010, a landmark procedure in France included the transplantation of eyelids and tear ducts as part of a comprehensive full-face transplant. Since then, eyelids have been incorporated into several face transplant surgeries, highlighting the advancements and possibilities in reconstructive transplantation.

Can a Blind Person See Again With an Eye Transplant?

Right now, a full eye transplant, where doctors replace the whole eye, can’t help a blind person see again. This is mainly because of the optic nerve, which links the eye to the brain. This nerve has more than a million fibers, and doctors can’t yet reconnect them if they’re cut or hurt in a way that would let someone see normally after getting a new eye.

But, there have been big improvements in other eye surgeries and treatments. For example, corneal transplants can bring back sight for people with certain corneal eye problems. Also, there’s exciting research happening with bionic eyes and retinal implants that might help some blind people see in a new way.

The main problems with doing a full eye transplant are the tricky job of fixing the optic nerve back together and how the body might react badly to the new eye. So, while the idea of replacing an entire eye is still something scientists are looking into, it’s not a cure for blindness yet.

The First Complete Human Eye Transplant 

NYU Langone Health’s team achieved a medical milestone by performing the first-ever complete eye transplant along with a facial transplant on Aaron James, who got badly hurt in an electrical accident. This groundbreaking surgery is testing new possibilities in eye repair and healing, but it’s still not sure if James will be able to see with the new eye.

Aaron James underwent this pioneering surgery hoping to look better and possibly get some of his sight back. The new eye is healthy and hasn’t been rejected, which often happens in transplants, marking a big moment in eye transplant history.

This surgery is pushing the limits by transplanting a whole eye, including the eyeball, blood vessels, and optic nerve. This is a key step in trying to find a cure for blindness. Still, getting the optic nerve to regrow is a big hurdle we need to clear to bring back sight.

The operation not only shows what eye transplants might do in the future but also celebrates the courage and optimism of people like Aaron James who are willing to try new medical treatments. What we learn from this surgery could spark more research and discoveries, hopefully leading to ways to bring back sight for others.

Even though the new eye is doing well, fixing the optic nerve, which is essential for sight, is still a big challenge. Seeing is a complex process that involves the brain as much as the eyes. If the optic nerve, carrying over a million nerve fibers, gets damaged, it cuts off communication between the eye and the brain, causing loss of sight.

This operation, which involved more than 140 surgeons, showed that we can transplant eye tissue and improve how a patient looks. However, restoring sight is still tough due to the difficulties in making the optic nerve regrow, as noted by Dr. Yvonne Ou, an ophthalmologist from the University of California, San Francisco. While the surgery has made great strides in terms of survival and appearance, the journey to restore vision continues to face significant obstacles.

Bionic Eye Implant

An 88-year-old woman in the UK has just received a groundbreaking bionic eye implant at Moorfields Eye Hospital. This new technology gives her hope to see again despite having geographic atrophy, a common type of dry age-related macular degeneration (AMD) that causes blind spots and has stopped her from enjoying gardening and painting.

Pixium Vision in France developed this implant, which is a tiny 2mm-wide microchip doctors placed under her retina. The system includes special glasses with a camera that sends images to a small computer. This computer uses AI to process the images and tells the glasses to send the info as an infrared beam to the microchip. Then, the chip turns this into an electrical signal that goes to the brain, letting the patient see visual signals.

The woman is excited about the implant, hoping it will let her get back to her hobbies and help others with eye problems too. But, getting used to this new way of seeing takes time, about six weeks of rehab after the surgery.

Dr. Mahi Muqit from Moorfields, who also teaches at the UCL Institute of Ophthalmology, said this successful operation could really help us understand how this treatment can work. This bionic eye implant is a big step forward in helping people with dry AMD see again and adds to the hospital’s history of eye care innovations, like the world’s first 3D-printed prosthetic eye announced in 2021.

Vision Renewed

In conclusion, the journey toward enabling the blind to see again through eye transplantation is fraught with challenges, yet it is undeniably filled with hope. While the full transplantation of an eye remains a complex endeavor due to obstacles such as optic nerve regeneration and immune rejection, significant strides in corneal transplants, bionic eyes, and stem cell therapy illuminate the path forward. The collective efforts of scientists, surgeons, and researchers around the world continue to push the boundaries of what we once believed possible. As we look to the future, the dream of restoring sight to those in darkness draws ever closer, fueled by the relentless pursuit of medical innovation and the enduring human spirit to overcome the impossible.