Using laser mouse causing cancer are laughable. LED (light emitting diode) cannot give you cancer. it's not laser. I took em apart before and it's a plain ol' red LED with lens on front of LED and detector w/ len on bottom. It seem very bright when you flip it upside down. It's just the len focusing the light to one spot making it look very bright. You can try swap Red LED to Green or Blue. It'll be soo cool!!

. At work, they swapped from balled mouse to Optical mouse. They use cheap mouse, one of mouse is a "drunken" one cuz it made pointer jittery and jumpy. I had gut to take it apart and unscrew the len holder and adjusted the LED to center then put it back together. It did fix the problem but no for long. I had to flip the mouse upside down and bang it then flip back and it works normally.

I also tease my co worker by lifting the mouse upward and shine the LED light at them to annoy.
Optical wireless mouse is my favorite. I hates wires cuz it creates drag when I tried to move around. I moved up from balled wireless mouse to Optical. I still have two old balled Logitech wireless mouse and still use on old Linux box. First one had no middle wheel and 2nd have middle wheel.
Catty