Snellen chart
Snellen chart: history of visual acuity testing from Hooke to ETDRS, with key milestones, optotype design, and contributions from Snellen, Donders, Sloan
Tag Landolt C
Edmond Landolt
Edmund Landolt (1846–1926): Swiss-French ophthalmologist who created the Landolt C optotype, advanced strabismus surgery, and retinal anatomy studies