Stenopaic slit
Stenopaic slit, brass, 38mm diameter used for high astigmatism or irregular refraction
Trial case, wooden, containing 72 trial lenses and trial frame, by S. Maw Son and Sons, 7-12 Aldersgate Street, London, England, 1901-1970.
Stenopaic slit, brass, 38mm diameter used for high astigmatism or irregular refraction