Al Limberg wrote: > Also, most of us have a right eye and a left eye > with only portions of the visual fields overlapping. And the "standard eye" structure supports this idea. Since the nose presents an obstacle for perpiheral vision, it looks like the retina has accommodated this physical limitation, giving your left eye a lot more peripheral vision to the left, and vice versa the right eye. ----------------------------------- http://www.4colorvision.com/standeye.htm#mosaic Retinal Topography Zones of the Retina (following Hogan, 1971) ....Central Foveola 0.35 mm diam ~175 PC's in diam. Fovea next zone out to 1.85 mm diam. Parafovea next zone out to 2.85 mm diam. Perifovea next zone out to 5.85 mm diam. ....Peripheral Near periphery 1.5 mm zone around the central retina Mid periphery 3.0 mm zone around near periphery Far periphery 9-10 mm wide on temporal side, 16 mm wide on nasal side=20 Ora serrata 2 mm wide on temporal side, 0.7-0.8 mm wide nasally ....Macula (a.k.a. Macula Lutea) Overlay of retinal area 2.0 mm. wide and 0.88 mm vertically centered on the Fovea ------------------------------------ Far peripheral vision is handled by 16 mm of retina from the fovea towards the nose, and only 9 to 10 mm of retina from fovea on the side of the temples. The lens, of course, causes the left to right inversion, which is why the retina closer to the nose gets to do the greater amount of peripheral vision. What this doesn't describe is how much far peripheral vision is available vertically. Evidently, less than horizontal peripheral vision, else they would have given it a specific number. Bert ---------------------------------------------------------------------- You can UNSUBSCRIBE from the OpenDTV list in two ways: - Using the UNSUBSCRIBE command in your user configuration settings at FreeLists.org - By sending a message to: opendtv-request@xxxxxxxxxxxxx with the word unsubscribe in the subject line.