Specific Gravity on RGP Contact Lenses

The specific gravity on rgp contact lenses is important to getting a good fit.

According to Dr Janice Jurkus, a professor at Illinois College of Optometry, instructs that an RGP lens should move smoothly along the vertical meridian. 

The RGP contact lens should glide about 1 to 2 mm up and down the cornea, each and every time the wearer blinks.

If the contact lens doesn't move enough, or if it moves too much, it should be changed to something with a different specific gravity on RGP contact lenses.