A Close up Look Infographic – #3 – Chameleon vision/Focusing
How do our eyes focus on moving objects and chameleon eyes zoom into their environment? Learn about the differences between the human eye and chameleon eyes in our latest infographic.
An insightful infographic written and illustrated by Gil Torten.
Enjoyed the infographic please keep it coming.. I wanted to ask that – we know that vision is sharp at center of eyes that is at fovea as compared to periphery (the reason given is that concentration of cones is more at fovea in contrast to lesser concentration of cones on periphery) but is there any other explanation for this other than above mentioned one (cause the relaying neurons behind cones or rods would be the ones which can make difference here right but I never understood it’s exact nature ) please help me out here..
I’m glad you enjoyed it!
So the cone density being much higher in the fovea is the main reason for higher visual acuity in the center of the visual field but there are a couple other interesting things that contribute.
First, the density of ganglion cells (the last cell in the retinal pathway before going to the brain) is much higher in the fovea – since these cells are very specific to particular types of signal and movement there is a much greater ability to discern things like edges and contrast.
Second, there’s some new research at UCLA showing that the different cell types actually are different across the retina based on location, particularly based on gene expression! For example, a rod photoreceptor might look morphologically very similar comparing the fovea to the periphery, but it might have very different genes expressed that contribute to the differences in these areas. This is still a very new area of research, but it appears that even cells that initially appear identical could be completely different in the genes they express, entirely based on location within the retina!
If you’re interested in that last point, check out this paper by Yirong Peng, a new faculty member at UCLA – https://pubmed.ncbi.nlm.nih.gov/30712875/ . It’s pretty exciting work!
Glad you enjoyed it!
So the higher concentration of cones in the fovea is the primary reason, but there are a couple other factors that play a role.
First, the density of ganglion cells (the last cell in the retinal pathway before it goes to the brain) is much higher in the fovea than the periphery. Since these cells are very sensitive to particular types of light signal and movement it heavily improves contrast and edge detection in the center of the visual field. There are also more overall ganglion cells per visual area, so you can notice more minute differences in the center of your vision.
Second, there’s some new research at UCLA showing that identical cell types could actually have very different gene expression entirely based on their location with the retina! For example, a rod photoreceptor in the fovea may appear morphologically and functionally very similar to one in the periphery, but it could have a very different gene expression profile changing the way it responds to light in ways that enhance foveal vision. If you’re interested in this, check out this paper by Yirong Peng, a new faculty member at UCLA – https://pubmed.ncbi.nlm.nih.gov/30712875/ . Pretty exciting work!
There are also more overall ganglion cells per visual area, so you can notice more minute differences in the center of your vision” -ohh now it makes sense
Great thanks for your attention
Surely I will go through the article
Thanks