Night Blindness

Night blindness is poor vision at night or in dim light. The cornea allows light to enter the eye. As light passes through the eye the iris changes shape by expanding and letting more light through or constricting and letting less light through to change pupil size.

What happens to the eye in low or no light?

Your eyes are constantly adjusting to light. When you’re in low or no light, your pupils (that black circle in the center of your eyes) will get bigger (dilate) so that more light will enter your eye. That light is then received by the retina – tissue in the back of your eye that houses all of the rod and cone cells. Cone cells help you see color. Rod cells help you see in the dark. When those rods are not working well because of a disease, injury, or condition, you can’t see as well or at all in the dark.