Optogenetics is a new technology, first discussed in 2004, using the ideas of neuroscience and microbial biology. The basic idea of optogentics is that light can activate and deactivate cells. It was observing algae that led to the lightbulb moment (excuse the pun). Algae would swim towards light, and scientists found a protein that was activated by the light and causing its behaviour.
Scientists then came up with the idea to remove the DNA (protein) from the algae, use gene therapy (attach it to a virus so it can be put into other animals) and then inserting into the animal cell. Once it was in the cell, it would replicate and fill the cell with these light sensitive proteins. They could then manipulate the cells using different coloured light. They also had the ability to add these viruses only to certain cells.
This technology is being investigated for brain diseases but also for vision conditions. Below is a TED talk that explains the discovery of optogenetics, how it is being researched and describes its use for vision conditions. Basically what it says is that even though the photoreceptor cells are damaged, light can still get into the retina. Optogenetics installs cells to act as a 'camera'. The video shows an experiment they have done with mice that, I must admit, got me a little emotional thinking about the possibility of seeing things again!
Below are links to optogenetics and vision articles.
Medical Daily, 11 May 2015
Science News, 15 May 2015
PLOS Biologue, 7 May 2015
Daily Mail, 11 May 2015
Image source: https://www.sciencenews.org/article/how-rewire-eye