Why does sudden bright light hurt your eyes? IE going outside after being in a dark room.

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Why does sudden bright light hurt your eyes? IE going outside after being in a dark room.

In: Biology

In the dark, your pupils have dialated to allow into your eye as much light as possible. When you suddenly step into the light, there too much light entering your eye and it causes pain because it takes a second for your iris to constrict your pupils.

First of all in a dark room your pupils will be dilated so when you enter a bright space your eyes catch a lot more light than is necessary for vision. Additionally your neuron activity is so that in a dark room it wants to catch all visual stimuli. It is heightened because the input is lessened. Therefore it is more sensitive. It reacts to photons and still wants to give you the same information as in daylight.

Subsequently your eye is overstimulated by catching a lot more light and your neurons firing even faster.