A for the preparation of dissection needles, microinjection needles are made from borosilicate glass capillaries with a Micropipette Puller B glass capillaries are heated and pulled to get extremely fine and sharp needles C instead of manipulating the dissection needle by hand, a micromanipulator is used. This dramatically reduces jittery movements that can puncture neighboring structures such as the brain or the heart. The micromanipulator allows precise puncturing around the lens with the needle’s movements controlled easily at less than 5 μm D clean needles are essential. Throughout the procedure, the needle progressively gets covered with a fatty substance that essentially blunts the needle. It is best to exchange it for a new one E embryo a week after a one-sided lensectomy in dorsal view. The left, lensectomized eye is regressing.