Blind (mask)

Blinding protects results from bias in how subjects respond or how outcomes are judged. With devices, full blinding is often hard, so studies commonly blind at least the people who assess the outcome.

A condition placed on an individual or group of individuals to keep them from knowing the intervention (or test) assignment of the subjects or subject specimens. For ophthalmic device studies, the term “blind” to describe this condition is inappropriate.

FDA guidance: Design Considerations for Pivotal Clinical Investigations for Medical Devices (November 2013), Section 11, Glossary