Talk:Eagle eye

Wiki Education Foundation-supported course assignment

This article was the subject of a Wiki Education Foundation-supported course assignment, between 7 September 2020 and 11 December 2020. Further details are available on the course page. Student editor(s): Ndennis1.

Above undated message substituted from Template:Dashboard.wikiedu.org assignment by PrimeBOT (talk) 20:22, 17 January 2022 (UTC)

Please move

Someone please move this to Eagle eye. See Human eye, for example. 2001:18E8:2:28AE:9CFC:20B5:255:D138 (talk) 18:56, 12 November 2012 (UTC)

 Done--McGeddon (talk) 19:00, 12 November 2012 (UTC)

I'm confused by some of the wording

The article has:

The phenomenon of an eagle turning its flexible head almost 270 degrees,[3] while sitting or flying, is attributed to the fact that when its large head is turned fully its eyes are also turned, unlike a human.

I don't understand that. If I turn my head to the left side my eyes are also turned. I'm guessing the article is trying to say that the bird turns its head while human employ a combination of turning her head and rotating her eyes to see around or behind her? The article also has:

Each eagle eyeball moves separately. The eyeball is so large and so tightly fit that the eagle can barely turn it within the socket.

I learned that the eyes can rotate within their sockets but it's not clear how much eagles employ eye rotation versus head turning. --Marc Kupper|talk 20:33, 12 November 2012 (UTC)

Visual acuity numbers are highly dubious.

This doesn't make sense: "the retina's fovea has one million cells per mm as compared to 200,000 per mm in humans"...it's not a linear feature - so "number of cells per millimeter" doesn't make sense. Number of cells per SQUARE millimeter is more likely. I couldn't find a number for the density of cells in the fovea. The human eye is on average 22mm in diameter and 72% of the interior is the retina - so that's an area of 1,000 square millimeters. The human eye is known to contain between 80 and 150 million rods & cones - which gives us an AVERAGE of 80,000 to 150,000 per square millimeter...but we know that the fovea has a greater density...so 200,000 per square millimeter seems like it might be a plausible number. But 200,000 per linear millimeter would suggest about 200,000² per square millimeter which is clearly impossible.

The number of optic nerves is important for visual acuity too. There are only a million of them in the human eye and half of those go to the fovea - which is only about one or two square millimeters. I we believe "200,000 per square millimeter" for the number of light-sensitive cells and half a million for the number of nerve cells, then that would mean that there is more than one nerve cell per light receptor in the fovea...which makes no sense - why could we possibly need more "wires" than we have information to put onto those wires? So I suspect that the number of photoreceptors per square millimeter in the fovea is more like a 250,000 to 300,000.

The other problem is that visual acuity isn't just about the raw number of cells. The outer areas of the human eye have only about one nerve fibre carrying information back to the brain for every 20 to 30 photoreceptors...which means that we get a spatial resolution that's much worse than the number of cells would suggest - because we're getting a combined signal from lots of cells being sent back to the brain.

Worse still, human eyes continually vibrate in their sockets to improve the spatial resolution of our vision - do eagles also do that? We state that they have trouble moving their eyes around - so maybe not. Because of that, our vision is better than (for example) a digital camera with the same number of pixels as we have cells. If the eagle can't do that trick - then maybe it doesn't see as well as the numbers suggest?

It would be interesting to ask how well-endowed the eagle's eye is with nerve fibres - because that might sharply limit it's ability to resolve small targets...or in some other way limit it to seeing only certain kinds of object with clarity.

At any rate - I think the analysis here is highly dubious.

SteveBaker (talk) 22:12, 12 November 2012 (UTC)

Sorry Gentlemen, we have used only book sources which we thought would be most reliable and we are not specialist in the field. If what you are saying is the right thing, please change the text suitably with references. Thanks for the interest taken to point out the anomalies or mistakes. --Nvvchar. 03:20, 13 November 2012 (UTC)

Lead

The lead needs improving from this vague current state. Widefox; talk 16:16, 8 May 2021 (UTC)