Notes about eyes

June 23, 2011 permalink


Research continues on whether humans (and other animals) have the ability to perceive magnetic fields:

Many birds have a compass in their eyes. Their retinas are loaded with a protein called cryptochrome, which is sensitive to the Earth’s magnetic fields. It’s possible that the birds can literally see these fields, overlaid on top of their normal vision. This remarkable sense allows them to keep their bearings when no other landmarks are visible.

But cryptochrome isn’t unique to birds – it’s an ancient protein with versions in all branches of life. In most cases, these proteins control daily rhythms. Humans, for example, have two cryptochromes – CRY1 and CRY2 – which help to control our body clocks. But Lauren Foley from the University of Massachusetts Medical School has found that CRY2 can double as a magnetic sensor.

Vision is amazing, even more so when you take into account the myriad other things that animals and insects can detect beyond just our “visible” EMF spectrum. See also: box jellyfish with their surprisingly complex (and human-like) set of 24 eyes.

June 11, 2010 permalink

Iphone Resolution

Phil Plait of Bad Astronomy lucidly explains display resolution, clearing up arguments about the iPhone 4’s retinal display technology:

Imagine you see a vehicle coming toward you on the highway from miles away. Is it a motorcycle with one headlight, or a car with two? As the vehicle approaches, the light splits into two, and you see it’s the headlights from a car. But when it was miles away, your eye couldn’t tell if it was one light or two. That’s because at that distance your eye couldn’t resolve the two headlights into two distinct sources of light.

The ability to see two sources very close together is called resolution.

DPI issues aside, the name “retinal display” is awfully confusing given that there’s similar terminology already in use for virtual retinal displays