How to convert the numbers from my gles to eye contacts?

Sphere, Cylinder and axis all refer to the type of lenses you have in your frames and how they fit, and yes, OD means 'right' and OS means 'left'. In order to know which power of contact lenses you should buy, you will have to have a contact lens fitting by a professional. Contact lens powers are different from gles because the lens is actually sitting on the eye instead of in front of it, so it would be difficult to guess which power to buy on your own.