10 January 2003
Vol 299, Issue 5604

About The Cover

Cover image expansion

COVER A human iris, as seen in a slit lamp photograph. Constriction of the pupils in bright light may be due in part to light acting on cells in the retina (other than the rods and cones that mediate vision), as suggested by studies in mice on pages 222 and 245. [Image: Charla Meyer, Peggy Winckowski]