Power Insight

The backs of our eyes are studded with millions of photoreceptors, cells in the retina triggered by light to help send electrical impulses to the brain. Differently-shaped ‘rod’ and ‘cone’ photoreceptors work to keep our vision precise and sensitive – and require a constant supply of energy. Here we see bundles cellular power stations – or mitochondria – highlighted in different colours around a single cone cell from a macaque monkey’s eye. To capture this level of detail, the retina was set in resin and a series of pictures taken while shaving away thin layers of tissue. The technique, called serial block face scanning electron microscopy, reveals the mitochondria have pointy 'tops' (left) and swollen bases (right), 10,000 times smaller than a bunch of asparagus. Researchers believe this arrangement helps with mitochondrial fusion – when the powerhouses join and rejuvenate, important to the health of retinal cells in monkeys and humans alike.

Written by John Ankers

John Ankers

Writer

A former researcher in systems biology, John is now an online biology tutor and professional coach supporting the wellbeing of scientists and NHS professionals. He's writing, too, of course.

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• Image from work by Matthew J. Hayes and colleagues
• University College London Institute of Ophthalmology, London UK
• Image originally published with a Creative Commons Attribution 4.0 International (CC BY 4.0)
• Published in Scientific Reports, September 2021