The American journal of the medical sciences (1827)
[Thorofare, N.J., etc.] Charles B. Slack [etc.] · leaf 126
122 Green, Detection and Measurement of Astigmatism. [Jan. of inclination, the dot tests by multiplying the dots and arranging them in rows of different degrees of inclination. The tests which I employ are made up of radiating lines, or of radiating rows of dots. The line tests, sixty in number,… … of the circle, like the hours and minutes on the dial of a clock (Fig. 1). Each line is equal in thickness to the lines employed by Snellen in the construction of No. XX. of his test-types, and is designed to be distinctly seen by an average eye at a distance of twenty feet. A second diagram is…
Medicine
Internet Archive · Smithsonian Libraries · Public domain (published before 1931). Free to use for anything.
