The amount of uridine uptake of the retina, the phagosome number and the acid phosphatase activity of the pigment epithelial cells after low dose laser treatment were studied. It was found that uridine uptake in the treated retina increased as early as one hour after laser treatment and then gradually returned to normal. The phagosome number showed a decrease 15 minutes after treatment followed by an increase. Finally it returned to normal 160 hours post-treatment. Higher acid phosphatase activity was found in the laser treated eye one hour and 16 hours after treatment and becoming normal again after 40 hours. It was postulated that the synthetic rate of the visual cells was stimulated by laser treatment. The increase in the shedding of the rod outer segments occurred simultaneously with the increase of phagocytic activity of the pigment epithelial cells. The increase of acid phosphatase activity of the pigment epithelial cells was a consequence of the increased phagocytic activity.