Deep in the back layer of our eyeballs, light triggers cells called photoreceptors – the long, rod-shaped cells stained green in this microscope image. Once activated, the photoreceptors send messages via nerve cells into the brain that enable us to see. Sometimes these photoreceptors break down and stop working properly, causing sight loss. But because the nerves wiring them to the brain are still intact, researchers are testing whether new genetic engineering techniques – known as optogenetics – can switch light-sensitivity back on and restore sight. Using a modified virus, they're adding a specially-designed light-activated protein molecule into cells at the back of the eye in blind mice. These molecular 'light switches' work amazingly well, turning on in response to light and bringing back the animals' vision. Although it's still early days, the exciting results bring hope that this technique could one day lead to new therapies for sight loss.
BPoD stands for Biomedical Picture of the Day. Managed by the MRC Laboratory of Medical Sciences until Jul 2023, it is now run independently by a dedicated team of scientists and writers. The website aims to engage everyone, young and old, in the wonders of biology, and its influence on medicine. The ever-growing archive of more than 4000 research images documents over a decade of progress. Explore the collection and see what you discover. Images are kindly provided for inclusion on this website through the generosity of scientists across the globe.
BPoD is also available in Catalan at www.bpod.cat with translations by the University of Valencia.