Regaining vision after 40 years of blindness
Modern medicine is achieving great successes and genetic therapy is one of the innovative technologies which gives us a lot of hopes for treating the conditions which had never been treatable before. The results of the experiment of using gene therapy for partial restoration of the vision in an person who had been completely blind for forty years is one of the examples of amazing things waiting for us in the future.
Genetic therapy with retinal ganglion cells
The results of the recent experiment are absolutely amazing since this is the first case of a person developing improvements in the eyesight due to the optogenetic treatment.
So far, optogenetics is focusing on a special alteration of genetic code which allows the scientists to reproduce channelrhodopsins. These are light-sensitive proteins important for human’s vision.
For the experiment, the researchers have used retinal ganglion cells after genetic modification. The scientists wanted to omit the bottom layers of non-functioning photoreceprors in the blind man and work with the top layer consisting of the ganglion cells in such a way as to make it photo-sensitive. The genetic code of ChrimsonR which is a name of channelrhodopsin was stored in a cold virus. ChrismonR is responsible for sensing amber light.
The virus with the code was injected and then, the researchers gave the man five months to get adapted to this genetic alteration in his body. According to the plan, the researchers wanted the man to have a series of practice with special googles. The task of these googles was using the wavelengths of an amber light to project visual images onto the man’s retina.
Surprisingly, it took less time than the researchers had expected for the man to start noticing the improvements in the vision.
The results of the experiment
Actually, it took the man only seven months of training to start experiencing spontaneous signs of the improvement in his eyesight.
The researchers are explaining this as the brain learning a language of communication with the alternated ganglion cells which is not the same as the one people normally have. The reports of the man were checked with EEG (electroencephalogram) which was used for measuring the brain electrical activity. This technique revealed real response of the man’s brain to the eye’s visual input. This means that the man is actually not blind anymore.
It is crucial to understand that in practice the man was able to distinguish large and simple objects surrounding him, however, this was not enough for making him capable of seeing smaller items. The road to mastering the technology to the point when blind people with be able to distinguish faces is still rather long. This requires a rather high resolution which cannot be achieved with the current technology. That is why the researchers do not want to give false hope to any blind people. Still, the mere fact that the person who has been blind for more than a half of his life (the man in the experiment is now 58 years old) is now capable of seeing things no matter how blurred or imperfect the eyesight is, is absolutely mind-blowing.
The man participating in this research is suffering from a genetic disorder known as retinitis pigmentosa. This malaise can destroy the vision by breaking the cells responsible for light absorption and conversion into brain signals.
Because of the disorder, the man in the experiment completely lost his vision forty years ago. Certainly, for such a person being able to see large obstacles on his way is of an enormous significance since for this purpose one ca n count only on a stick.
The researchers reported that there are more people participating in this experiment, however, the Covid-19 epidemic made it rather difficult for them to appear in the medical centre for practising with goggles rather complicated. The situation didn’t allow the scientists to study the participants in an appropriate way. Because of that reason, the researchers cannot be sure about the respond of other participants to the treatment. The researchers are treating the results of the study as a proof of the possibility of their technology working, however, they need to replicate the results in other people to make sure of its effect on the vision.