Snellen's ophthalmic vectis, steel, nickel-plated, by Collin of Paris, 1870-1930 Snellen's ophthalmic vectis 1870-1930
Landolt's ophthalmic vectis, steel, nickel-plated, by Collin of Paris, 1870-1930 Landolt's ophthalmic vectis 1870-1930
Combined vectis and strabismus hook, steel, by Young of Edinburgh, late 19th century Combined vectis and strabismus hook 1871-1900