Around 1760 Benjamin Martin, scientist and instrument maker, invented a novel style of “visual glasses” with inserts surrounding a small round lens. The inserts, commonly made of horn or tortoiseshell, were meant to restrict the amount of light reaching the eyes, protecting them from light overload. Martin's Margins were in common use from early 1760s - 1820.
Martin's Margins spectacles with green lenses. Steel, C bridge, double hinged temples with large ring ends, ca 1780's
Steel Martins Margins spectacles, round lens, C bridge, straight temples with large ring ends. (broken insert)
Martins Margins spectacles. Steel, clear round lens, C bridge, double hinged temples with large teardrop ends. late 18th century
Tortoiseshell short-arm wig spectacles, ca 1825, Martin's margins style with broad curved bridge, straight temples and temple pads