Mitochondria in cone photoreceptors act as microlenses to enhance photon delivery and confer directional sensitivity to light.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 35235359.
- Also identified by DOI 10.1126/sciadv.abn2070 and PMC identifier 8890704.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Mammalian photoreceptors aggregate numerous mitochondria, organelles chiefly for energy production, in the ellipsoid region immediately adjacent to the light-sensitive outer segment to support the high metabolic demands of phototransduction. However, these complex, lipid-rich organelles are also poised to affect light passage into the outer segment. Here, we show, via live imaging and simulations, that despite this risk of light scattering or absorption, these tightly packed mitochondria "focus" light for entry into the outer segment and that mitochondrial remodeling affects such light concentration. This "microlens"-like feature of cone mitochondria delivers light with an angular dependence akin to the Stiles-Crawford effect (SCE), providing a simple explanation for this essential visual phenomenon that improves resolution. This new insight into the optical role of mitochondria is relevant for the interpretation of clinical ophthalmological imaging, lending support for the use of SCE as an early diagnostic tool in retinal disease.