When you press on the corners of your eyes, why do you see little lights off to !
Question:
When you press on the corners of your eyes, why do you see little lights off to the sides?
I used to do it a lot and thought it was cool and always wondered why...
Answers:
Pressing on the corner of your eye will cause you to push on the wall of the eye, which will push on the retina in that area. As the retina can't 'feel', but can respond as light sensation, you pick up the pressing as a light sensation.
Some people see these light flashes when they move their eyes back and forth, or suddenly back or forth, or left or right. When they do this, the vitreous gel will pull on the front of the retina causing these light flashes. This is called photopsia.
Some people will pull on the retina hard enough to cause a tear. If this occurs, they may also tear a small vessel within the retina. They'd also notice lots of little floaters at the same time as the light flashes. The floaters would continue even when the flashing stops. If one has a retinal tear, the vitreous fluid can get beneath the retina and allow it to 'float' into the center of the eye. That's called a retinal detachment.
If one had a retinal detachment, one would see a shadow or curtain-like defect in their vision of that eye. The retina has to be against the wall, against the choroidal vessel layer (which is the blue or brown or green or grey or ? color in front of the eye) for the photoreceptors to work. They need the oxygen.
Pressing on the eye usually won't cause a retinal tear. But if you're pushing hard enough to get light flashes, you are stretching something, and that something is pulling or stimulating the retina...