Polariscopes, Frame heaters
A polariscope is an optical inspection device, whic is designed to detect internal stresses in glass and other transparent materials such as plastics, synthetic resins, etc. A polariscope is composed chiefly of a light source and two crossed polarized lenses. Used in Opthalmology. Frame heater - a device which warms plastic spectacle frames in order to soften its material sufficiently to allow insertion of lenses and their adjustment. Used in Opthalmology.
