Our purpose was to study the effect of continuous wave (CW) green argon laser (514 nm) exposure on rose bengal-stained cornea. Following staining with rose bengal (1%), the corneas of 48 albino guinea pigs were exposed to different power levels of argon laser, ranging between 0.04 and 0.8 W. The beam diameter ranged between 50 and 200 microns, and exposure time was 0.1 sec. Histology revealed minimal tissue coagulation at 0.05 W and 50 microns. Moderate coagulation of the anterior stromal lamellae was found at power levels of 0.07-0.6 W and a beam diameter of 100-200 microns. At power levels of 0.7 and 0.8 W, lamellar disruption was also noted. Our data indicate that 1% rose bengal is a good photosensitizer for superficial corneal stromal photocoagulation.