Short sight, long sight and astigmatism : an elementary guide to the refraction of the eye / by George Frederick Helm.

Licence: Public Domain Mark

Credit: Short sight, long sight and astigmatism : an elementary guide to the refraction of the eye / by George Frederick Helm. Source: Wellcome Collection.

Provider: This material has been provided by University of Bristol Library. The original may be consulted at University of Bristol Library.