Spectacles for microscopists and astronomers

A special set of spectacles with the lenses reversed (concave anteriorly) were fabricated for use with microscopic and/or telescopic eyepieces in order to reduce the vertex distance and improve the useful field of view. Although these spectacles were found to be of limited use to microscopists, they were essential to the astronomer whose astigmatism could not be corrected with contact lenses.