Even if a screw-driver is being used as intended, safety glasses are still required. There are many different types and sizes of screw-drivers and there is no such thing as a ‘universal’ bit size. In addition, there are many sizes and shapes fasteners and a unique bit that is to be used for each. Under no circumstances should a screw-driver ever be used as a pry-bar in any capacity!
First identify the type and size of screw-driver that is required for your application. Be careful to select the right size in order not to damage the head of the bolt or screw. Once the correct size and type of screw-driver has been determined, match the pattern on the bit with the pattern in the bolt/screw and rotate in the desired direction. “Lefty-loosey; righty-tightey” is a common term coined to remember what direction to turn. Ensure that sufficient downward force is being applied to the screw-driver to ensure that the bit does not jump groves that would ultimately destroy the head of the bolt/screw. If the screw-driver constantly skips over the groves, reconsider the bit that you are using.