hey, it really depends on a few things. strabismus, turning eye, or a squint is due to a weekness in the ocular muscles in one of the quadrents, ie to allow the eye to move left, right, up, and down.
if your eye is squinting on its own and is always present ie see it is pictures, then you might need a prism which is placed onto your glasses to align the eye. if the turn compinsated,ie only present during the cover test and straighens up again, then its due to mabye the eye being tired, ie pc work..
I would not worry, the CAA have a section on the prism requirment for certification, thats the best option..
Im not an optician, but a commercial pilot, we learn this stuff in ground school..