Visual affections are very hard to treat, since the human eye represents an incredible organ, this being capable to differentiate between a huge number of colors, mechanically adjusting to various lighting conditions found in the environment, and, if we are speaking in pure technical terms, it has around 50 f-stops, similar to a very high tech camera.
Light enters into our eyeballs and it is then captured by photoreceptive proteins located inside the retina (the cones and the rods). From here, all details are sent towards the human brain via a ganglion and numerous bipolar cells found behind cones and rods. The brain is capable of adjusting to the ever-changing data flux coming from the eyes, just like when photographer are using various color filters (or tinted sunglasses to put it in a simpler) in an almost imperceptible way.
In the majority of degenerative diseases that are affecting the eyes, like macular degeneration and retinitis pigmentosa, a large amount of cones and rods are destroyed over time, leaving more than a quarter of all sufferers of such medical conditions legally blind. But, the curious part is messenger cells remain mainly intact during the destructive process.
This is exactly what today’s scientists are looking to make experiments on and they have been performing such experiments with channelrhodopsin-2, this being one of the light-sensitive proteins discovered in several species of green algae. Specialists have had success in people having retinitis pigmentosa and channelrhodopsin-2 protein can be incorporated into the human retina through gene therapy methods, bypassing all rod and cone systems in the way and permitting the ganglion cells to detect light waves by themselves.
The medical experiments started around a decade ago, when American researchers implemented the light-sensitive protein into several blind lab rats, and their approach worked when they tried to restore the mice vision during the first attempt.
A few years later after these initial and successful experiments, companies in the research domain took all research initiative in order to begin their experiments on people. And during recent weeks, having also the approval of US authorities, a small number of clinical tests will start on more than 10 sufferers of different visual deficiencies before 2016.
However, the entire procedure might not bring the entire restoration of a person’s vision, since human ganglion cells in the nervous system are not necessarily designed to detect several levels of light waves, but only to process the signals received by the eye.
The channelrhodopsin-2 proteins are more than 1,000 times less light sensitive than a fully functioning network of cones and rods. So, even when the revolutionary protein is helping the visual chain to perform better, there might remain some signs of color blindness for the treated people. The protein addition is generally only responding to a rather narrow selection of wavelengths.
The human brain can make the necessary adjustments to adapt to various spaces, though. This is one of the parts that remain to be further analyzed during the studies by testing them on human eye. In the course of the next year, experts might have a treatment for individuals suffering from degenerating vision.
Image source: Vertigo-dizziness
