Placing a magnifying glass between the object and the eye allows the object to be brought closer to the eye, and the eye can focus on the virtual image formed, preferably at the clearest viewing distance. The regular magnification, M, is the ratio between the angle θ' subtended by the image and the angle θ subtended by the object.

A magnifying glass is any positive lens with a focal length less than 250mm. The approximate magnification M provided by the lens is calculated by dividing its focal length by 250.

Equation: M= θ'/θ =(250mm/f)

M=250mm/25mm = x10

Calculate of lens

I want try with this product. X10 Diameter 75mm  with 2.5cm of  distance between the display & lens