Weird Eye Thing!

[daniela]

I don't really know how to explain this, so I'll just use an example.

Last night I was lying in bed, TV off, computer off. As I turned to my side towards the TV I could see the reflection of my computer mouse light which is bright blue. Only thing is when I looked directly at the blue light (in the reflection still) it disappeared! It's only when I don't look right at it I can see it. It's really odd! It must have something to do with the eye, but question is what?!

This has happened to me a few times with different lights and not necessarily in a reflection... hope someone can shed some light on this! Thanks.

[john91]

I don't know if this is the effect you have noticed, but it is possible to see faint objects better if you don't look at them directly, its called 'averted vision' and astronomers use it to see faint stars etc, just put 'averted vision' in google for more detail.

[Quizmonkey]

If you felt okay after, this answer's probably irrelevant - but you're describing what for me is the first sign of a migraine. Luckily I get these very rarely (one a year or rarer) - but it always starts with a 'hole' in my vision in one eye - when I can't see a small object unless I look away from it - then the hole gets bigger and shimmery. I know then to lie down and sleep in a darkened room until it all passes!

[Clanad]

A simplified version of how the eye "sees" is that the photoreceptor sheet at the back of the eye recieves vision through rods and cones.  One (cones) focuses centrally and detects color and one (rods) picks up motion peripherally (which is the reason you see movement out of the "corner" of your eye).  Additionally, the sheet of photoreceptors at the back of the eye where the received light is transmitted is much like a sheet of film at the back of a camera. But it has a hole in it. At one location, called the optic nerve head, processes of neurons collect together and pass as a bundle through the photoreceptor sheet to form the optic nerve, which carries information from the eye to the rest of the brain. At this location, there are no photoreceptors, and hence the brain gets no information from the eye about this particular part of the picture of the world. Because of this, you should have a "blind spot" (actually two, one for each eye), a place pretty much in the middle of what you can see where you can't see. The blind spot for each individual is usually different is size and actual location, so a slight movement of the head can eliminate vision in one or both eyes.  Remember, the visual "picture" is reversed vertically on the photoreceptor sheet, but is processed by the brain to give us the correct information about what we are seeing...


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[daniela]

John, I forgot to mention that detail, but yes, it does get brighter and clearer when I look away from it. That's really interesting.

Quizmonkey- Nope no migraine. Luckily I've never had one!

Clanad - very detailed answer, thank you. That was really interesting to read!

So it's not just me after all! Just as well hehe.