Visual Acuity through Various Types and Grades of Sun Glasses*

Abstract

The visual acuity of 27 subjects was determined with a new psychometric device and compared with their visual acuity when looking through three types of sun glasses prepared by grinding and polishing the lens to curvature, by bending polished plate glass, and by bending drawn sheet glass. No significant effect between the different types was discovered. The visual acuity of 43 other subjects was similarly determined and compared to their visual acuity while looking through three grades of resolving power in sun glasses made by the process of bending drawn sheet glass. No significant effect of the different optical resolving powers was found. It is concluded that no presently employed method of manufacturing sun glasses has, in itself, any superiority with regard to sharpness of seeing.