Feb 27, 2017
Why do I see spots after a bright light?
Great question from a young patient last week... "Why do I see spots after a bright light?" To understand why, lets first talk about how the eye works. When any light hits the back of the eye (retina) a chemical reaction occurs that converts the light energy into electrical/nerve energy that goes to the brain. This reaction takes fuel that is constantly being produced by the eye and then used up - over and over again.Under normal circumstances the fuel's speed-of-creation can keep up with the fuel's speed-of-use. However, when the eye is presented with intense brightness like a camera flash (or eye exam!), the fuel is used up much faster than production. Because there is no/low fuel after the flash, this flashed zone of the retina appears dark because there is no creation of the electrical/nervous energy until the fuel regenerates. dr.j