Begin by using a dip net to capture the tadpoles from their tanks and transfer them to a fresh tank filled with 0.005%benzocaine solution for anesthesia. Then wait for a few minutes to allow the tadpoles to stop reacting to stimuli. Now, capture the anesthetized tadpole with a spoon and carefully place it with its dorsal side up in the center of a small Petri dish lined with moist tissue.
Then position the specimen under the stereo microscope. Using a 0.2 millimeter diameter pin attached to a pin holder, carefully insert the tool on the dorsal side of the right eye, piercing the retina, and passing through completely. Then rotate the Petri dish 180 degrees and puncture the left eye.
Carefully immerse the Petri dish containing the lesioned tadpole into a large tank with one liter of rearing water. Monitor the tadpoles until they are fully awakened. Retinal sections of tadpoles subjected to mechanical injury showed the retinal lesion in all layers of the tissue while remaining limited to the puncture site.
