Visolett magnifier. Evaluation and optics
G. Fonda
The Visolett is a glass, nonspectacle magnifier that rests on the paper,
producing 1.8X to 2.5X magnification. It is one of the most useful
nonspectacle magnifiers, because it is simple to use and diffusely
concentrates illumination on its own field, enhancing the magnification.
The optics differ from usual hand magnifiers in that the magnification does
not increase with the dioptric power.