In the Gospel of John, disciples of
Jesus see a blind man and turn to Jesus, asking if the man or his father had
sinned to put him is such a decrepit state. According to the story, Jesus said
that it was neither, and healed him of his blindness, which he declared a work
of God. Whether you buy the story or not, it gives us insight into how
marginalized those experiencing blindness have been in history. Unfortunately,
physicians do not have the miraculous capabilities that Jesus was said to have,
and so 2.3% of Americans still experience blindness. However, many incredible steps are being made
in science to try to understand the mechanisms behind blindness and use
resources available in other species to cure human blindness.
The National Institute of Health funded a study that took a
protein from green algae and inserted it in the retina of blind mice. This
specific protein (channelrhodopsin-2 or ChR2)
is light sensitive and fires an action potential when exposed to light, helping
the process of photosynthesis in green algae. However, when it is inserted into
mice that are bread to be blind, it has incredible effects. Blind mice who undergo
the ChR2 protein injection were suddenly able to complete visual behavioral tasks,
such as following blinking light for a reward of food. Researchers determined that
the majority of ChR2 treated mice received input into their visual cortex, when
such input was absent prior to treatment.
The implications of such research
are huge, in that it makes a cure for blindness in humans seem much more
attainable in the near future. Clinical trials have not yet been taken on, but The
National Eye Institute (NEI), has voiced its desire to take research a step further
and explore how more complex visual stimulus can be processed through similar
mechanisms as the ChR2 treatment that mice experienced. Through their work, we
might soon be able to tackle such huge and debilitating conditions such as
blindness in humans.
https://www.nih.gov/news-events/news-releases/blind-mice-recover-visual-responses-using-protein-green-algae
This would be revolutionary if it applied to more diseases of the eye (article states that the protein cures something similar to retinitis pigmentosa). When I worked at a retina clinic, about 50% of the cases we saw were diabetic retinopathy (DR), and the other 50% macular degeneration (MD). DR is usually easily treated by maintaining control of blood sugar so that blood pressure and doesn't increase too much and release blood from eye vessels into the vitreous humor, however, macular degeneration is still a mystery. We know that it has a genetic component, but really, not much else is known or can be done. MD consists of macular cells (the middle of the retina) dying, usually when the individual hits 60-70 years of age. It's really terrible because your central vision is basically decimated. The only treatments available as of now are steroidal shots into the eyeball which reduce the swelling and improves vision slightly, but only slows the degeneration, so it would be really cool to see something like this for MD!
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