Outside in bright sun, the light exposure uses up the chemicals. Unfortunately, the damaged retina may be unable to rapidly produce new chemicals and vision may seem to decrease or dark spots may appear. This is the same process we all experience when someone takes a flash picture of us, and we see a dark afterimage for a short period. Unfortunately, in macular degeneration the spot or decrease in vision may last much longer. General light sensitivity may increase in patients with macular degeneration.
Some patients are unable to tolerate bright lights in their home.
Due to this photophobia, patients usually begin wearing sunglasses to help cope with the bright lights. When scars form in the retina they serve as reflectors to scatter light back off the retina causing further intolerance to bright lights. The majority of the rod cells are located in the peripheral retina and are thus unaffected by macular degeneration. Rod cells function in lower levels of light allowing the patient to have better vision. The macula has the highest concentration of cones, the cells that provide color vision.