It is widely believed the human body has approximately 100 organs. However, there is no universally standard definition of what constitutes an organ. Generally speaking, an organ is a collection of tissues joined in a structural unit to serve a common function. Our largest organ is our skin. Five organs are considered vital for survival, the heart, brain, kidneys, liver, and lungs. It is fair to say we can’t remain alive if any of the five stops working. Our life does not depend on them, but our eyes are organs vital to a normal life.

Unfortunately, organs are not perfect. They can wear out, get damaged, acquire a disease, or lose functionality due to any number of afflictions. Cancer is perhaps the most devastating. The progress of medical research has produced amazing treatment options over recent years. Traditionally, the options have been cut (surgery), burn (radiation), or poison (chemotherapy) the cancer. More recently, medical research has focused on the cutting edge of immunotherapy treatment where doctors can target markers on the cancer cells and cause the immune system to attack the cancer cells and destroy them.

Another approach, written about quite a few times in my blog, is regenerative medicine. For example, diseased liver tissue can potentially be replaced by using the patients pluripotent stem cells and 3-D printing to create tissue which can be implanted in the liver. The artificial parts of the printed tissue dissolves into the body and the stem cells become liver cells and grow into the diseased organ. Great progress is being made in this area. See Health Attitude: Unraveling and Solving the Complexities of Healthcare.

The ultimate solution in many cases in the future may be to completely replace a defective organ with an artificial one. Replacing defective joints has become commonplace. You can find stories in my blog about my experience in having my knee joint and shoulder joint replaced with artificial joints. In October, my other shoulder will become artificial. One more step toward becoming a bionic man, and another step toward the singularity. For more about the singularity, see
Robot Attitude: How Robots and Artificial Intelligence Will Make Our Lives Better. 

I don’t know for which of all human organs it would be most difficult to create an artificial replacement. The human eye is a likely candidate. An international team of scientists at the Hong Kong University of Science and Technology (HKUST) has been working on the challenge for almost ten years. The team has recently had a breakthrough and has developed the world’s first 3D artificial eye with capabilities better than existing bionic eyes. Existing artificial eyes are basically spectacles with external cables. They do allow the wearer to see something on a computer screen, but the 2D resolution is poor. 

The Electrochemical Eye (EC-Eye) developed at HKUST, replicates the structure of a human eye for the first time. The breakthrough is a 3-D artificial retina constructed from nanowire light sensors. The nanowire sensors mimic the photoreceptors in human retinas. A research experiment replicated a visual signal transmission of what the artificial eye sees and displayed it on a computer monitor. The complexity of what has been created is mind-boggling. See picture above.

The researchers believe the artificial eye will ultimately have sharper vision than a human eye, and offer additional functions such as the ability to see in the dark. The first beneficiary of the artificial eyes will likely be humanoid robots, but ultimately, the artificial eyes will offer new hope to millions of patients with visual impairment.

Prof. Fan Zhiyong and Dr. Gu Leilei from the Department of Electronic and Computer Engineering at HKUST have been working on this research for nine years. They are collaborating with researchers at the University of California, Berkeley. The next step will be to connect the nanowires to the human nerves and create vision in the brain. Many enhancements are needed, but this is not science fiction. I believe the medical capabilities we see in the next 10 years across all areas of medicine will far exceed what we saw in the last 100 years. 

Note: You may wonder how big is a nanowire. A nanowire has a dimension on the order of a nanometer. Visualize a human hair. One hair could contain 65,000 nanowires. If you think of the relationship between one mile and one inch, one mile is 63,360 inches. A human red blood cell is 6,000-8,000nm across,  and the diameter of the coronavirus is 50-100nm.