• The Visolett is a glass, nonspectacle magnifier that rests on the paper, producing 1.8 × to 2.5 × 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.
Fonda G. Visolett MagnifierEvaluation and Optics. Arch Ophthalmol. 1976;94(9):1614-1615. doi:10.1001/archopht.1976.03910040444019