Why cant the sight of a blind person be restored?

Question

Why cant blind see even tho they got eyes? Why cant people donate an eye, we dont need 2?

Answer 1

The reason entire eyes currently can't be transplanted, as a liver or kidney is, is because the eye is not actually a separate organ in that same sense. The eye is directly hooked up to the brain, so in many ways it is simply an extension of part of the brain. The impulses from the optic nerve feed directly into the brain, the same as your ears do. They do not go through the spinal cord. It's not as simple as taking out the old non-functioning eye and popping in a new one. Currently there is no way to plug the optic nerve into the brain. And if you cut a nerve, it tends to die and stay dead. To remove the eye from a donor, you would have to cut that optic nerve. Then, you would have to manage to reattach it, undamaged in the recipient. That's a lot of fine work in an area we don't have much knowledge for. Currently, if you have a damaged lens, it can be removed and replaced. The retina can even be reattached in many cases. But if there is a problem with an eye which prevents it from sending impulses to the brain, the brain will shut off the eye. And once the brain shuts off an eye, it's very difficult to get it to "turn it back on" again. The other problem is that you really do need 2 eyes to see correctly. You have stereo vision, with the images from both eyes giving you an image that the brain fuses. It is the reason you have depth perception, for one thing, and that requires two working eyes. Although you can certainly adapt to having vision in only one eye, it does impact on your vision. You have less of a visual field, and will have to rotate your head more often to be able to see a person on your blind eye side. If you want an idea of how much losing one eye can handicap you, just try covering one. You will discover very quickly how much you depend on having two working eyes, and how much of the world around you will disappear from your view. Hopefully someday perhaps, transplanting eyes and restoring vision to the blind will be possible. But for right now there are just too many obstacles. I don't think though, we are likely to see many live donor transplants, though. We can live with only one kidney without really impacting much on daily life or altering function. That just isn't possible to do when you take one eye, and leave one.

Answer 2

blindness may be due to a multitude of reasons, starting with trachoma (a disease affecting the conjunctive, the outermost later of the eyeball) to diabetes, (which messes up with the blood capillaries supplying the retina) to a brain tumour affecting the occipital lobe (the area of the brain that processes the visual information).
there are some types of blindnesses that can be medically or surgically remedied, like diseases of the eye lens, in which we can replace the natural lens with an artificial one.
and a healthy person cannot donate an eye because the donor's body simply will not accept it, due to an immune reaction.
if you know someone who is suffering from a condition of the eye that has rendered them blind, please get their eyes evaluated by an ophthalmologist. it may turn out to be a condition that can be remedied.

Answer 3

Yes, usually damage to the optic nerve or brain visual centre can't be cured. However, if the cause is physical, sometimes it is possible to restore someone's sight (through corneal graft, for instance); and there have even been cases of people who were born blind and had their sight restored later in life.

Answer 4

Sometimes, it's not just about the eyes. The brain has to interpret images that are sent from the eyes from the optic nerve. If there is damage to the center in the brain that interprets the information, it won't matter if there are eyes or not. The person won't be able to see.