Landolt

Landolt is a surname of German-language origin, found primarily in Switzerland, Germany, and Austria, with members of the diaspora in other regions. Variants include Landolt and, less commonly, Landoldt. In addition to its use as a family name, Landolt is associated with a widely used ophthalmological tool: the Landolt C, or Landolt ring. This optotype consists of a circular ring with a small gap cut into the circumference, and the gap’s orientation can be varied. During visual acuity testing, observers are asked to identify the direction of the gap at different sizes.

The Landolt C is valued for being language-independent and easy to standardize, and it remains in common use in clinical optometry, ophthalmology, and vision research, alongside other acuity charts. It is named after a Swiss ophthalmologist who introduced the design in the late 19th to early 20th century, reflecting a tradition of precise measurement in eye care.

Notable people with the Landolt surname include scientists, physicians, and scholars who have contributed to various fields. Beyond individuals, the name appears in place names, institutions, and historical references in areas where German-speaking communities have been established.