Saturday, September 12, 2009

Light Bulbs in your Field of View

I've read your response about incandescent lights being generally eye safe to look at but I still have some questions. Is a clear bulb safe even if its within your field of view? If you were watching TV would it be damaging to the eyes to have the image of the filament sit on your periphery? I understand the eye moves while watching TV so it wouldn't stay on the same location on the retina. Also what if it was right next to your central vision, say a clear bulb next to your television, would it cause damage then? if you were watching the TV for hours upon hours?. I've tried to find the answer to these questions about how dangerous the clear incandescent light bulbs are but there doesn't seem to be much information regarding it, especially light damage on the peripheral of your eye.

An incandescent lightbulb in your field of view over an extended period of time is generally safe to view, whether it is in the center of your view or in the peripheral. Your eyes will provide you with some feedback if it is not good. If your eyes squint, or you feel discomfort, then that is your body telling you that maybe it isn't a good idea.

Thursday, April 23, 2009

Can staring at an L.E.D. flashight be dangerous?

If you have time will you please settle a family dispute. will staring at an l.e.d. flashlight or shining it directly into someone's eyes be damaging?

My first thought is that it's always the best policy simply to not stare into any light sources.

It is unlikely that you are going to cause damage to someone's eyes by accidentally, or momentarily, shining it into their eyes. L.E.D. flashlights are more powerful than incadescent ones, but they are still generally safer than laser pointers. The reason for this is that the beam from a laser pointer will focus to a smaller spot on your retina than the beam from a flashlight. (Technically speaking, the laser pointer is a point source, the flashlight is an extended source.)

I hope that answer restores peace to your family.