Backwards retina: mitochondria focus light (Introduction)

by David Turell , Tuesday, April 05, 2022, 21:17 (753 days ago) @ David Turell

A study in squirrels:

https://www.quantamagazine.org/mitochondria-double-as-tiny-lenses-in-the-eye-20220405/

"A study published last month in Science Advances found that inside mammalian eyes, mitochondria, the organelles that power cells, may serve a second role as microscopic lenses, helping to focus light on the photoreceptor pigments that convert the light into neural signals for the brain to interpret.

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"The lens at the very front of the eye focuses light from the environment onto a thin layer of tissue called the retina in the back. There, photoreceptor cells — cones that paint our world in color and rods that help us navigate in low light — absorb the light and translate it into nerve signals that propagate into the brain. But light-sensitive pigments sit at the very ends of photoreceptors, right behind a thick bundle of mitochondria. The odd placement of this bundle turns the mitochondria into seemingly unnecessary, light-scattering obstacles.

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"Instead of being obstacles, the mitochondrial bundles seem to play a critical role in helping to funnel as much light as possible to the photoreceptors with minimal loss, Li said.

"With simulations, he and his colleagues confirmed that the lens effect was caused primarily by the mitochondrial bundle itself, not the membrane surrounding it (though the membrane played a role).

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"Li and his colleagues think that what they saw in ground squirrels is also likely to occur in humans and other primates, who have very similar cone structures. They suggested that it could even explain a phenomenon, first reported in 1933 and called the Stiles-Crawford effect, in which light passing through the very center of the pupil is perceived as brighter than light entering at an angle. Because that central light may be more aligned with the mitochondrial bundles, the researchers think that it may get focused better onto a cone’s pigments. They suggest that measuring the Stiles-Crawford effect might help with the early detection of retinal diseases, since many of them cause damage and changes to mitochondria. Li’s team hopes to analyze how diseased mitochondria may focus light differently.

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"At least in cones, these mitochondria may have evolved to serve as microlenses because their membranes are made up of lipids, which have a natural ability to bend light, Li said. “They’re just the best material to achieve this function.'”

Comment: so our crazy backward retina is found to be marvelously designed for sharp vision. The complaints about God doing it improperly can be cast aside.