Light adaptation is the adjustment of the eyes when we move from darkness into an area that is illuminated. During this adjustment period the sensitivity of the retina decreases. The cones of the eyes begin reacting to the brightness of the light and become more active than the rods of the eye. This increases the accuracy of vision and the sensation of color. You know how when you leave a dark room for the bright light of a sunny day there are spots and color distortion that eventually fade away This is light adaptation. The other end of the spectrum is dark adaptation which is the adjustment from an illuminated area to darkness.