Blindness:-
Blindness is a condition in which person is not able to see things. It occurs due to physiological or neurological defects. Eyesight is the greatest thing which enables the person to see the beautiful colors of this world. Many features work together to make the person see things like, retina, cornea and iris. These factors together let the eye focus the light and enable the eye to see things. Brain is the most important part of the body. When an eye wants to see something, it sends signals to the brain. Brain after receiving the signals sends back the command to the eye through receptors which make the eye see things and focus on the light. But some people who can't see things properly, they have this problem since birth. The main cause is that either the child's eye components like cornea, irises etc do not develop properly. Sometimes it happens that your baby's eye might seem normal but in fact, his brain does not receive the optic signals from the eye properly. The nerve does not function in a normal way that is why the brain does not receive signals properly.

There are various reasons that why the person gets blind. As it is also genetic disorder that is why either the individual gets it from his parents or some kind of accident can also cause this disorder. Sometimes blindness occurs due to some disease like diabetes or eye disease cataracts in which an individual is completely blind or partially blind. There are some people who are blind but they can see things in the form of shadows or light.

Gene Therapy:-
Gene therapy is a very useful technique of genetics which has helped in treating various diseases. Sometimes the treatment becomes helpful for some people and some people get sicker because of this therapy. But still this technique has been applied to treat defects and disorders.

The test of gene therapy was held on three young adults. They suffered from blindness due to some genetic disease. When these adults were undergone gene therapy, they showed tremendous results and their eyesight improved a lot. They didn't show any side effects against this therapy.

Viral Vector and treatment:
For the process of gene therapy, first viral vectors are prepared. Scientists take out virus's genetic material so that it does not create any harmful effects in the body when inserted. Then they inserted desired genes which had to be administered in the body to treat blindness. Through this method, scientists develop viral vectors. For treating blindness, scientists used a special virus called adeno-associated viral vector which is also called as rAAV2-hRPE65. This virus was used as the vector for treating blindness because scientists knew its properties very well. These viruses can very well target the retinal cells and have the ability to stay for the longer time in the cells.

The viral vector is administered near the retina in the form of an injection. This way virus has less chance to create any side effects. Though the method of insertion f viral vector is new but many eye defects are treated with the injection method.

Eye is a simple organ. Treatment of blindness with gene therapy is easy because there is one gene defect involved in this disorder unlike other defects like cancer which have multiple gene disorders.

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