Catalogue Number: 1476
Sub-Category: Equipment, other clinical
Year Of Publication/Manufacture: c1930
Time Period: 1900 to 1939
Description Of Item: Four examples: (A) Lightweight timber disc on timber handle. Central glass lens +5.00DS. Concentric black & white rings on paper applied to surface of disc. Diam: 16.2cm, Length including handle: 25.3cm. (B) Metal disc 23 mm dia Black and white concentric rings on front, black crackle finish on back. Plastic handle 120 mm long fitted to metal stem. Plus lens in black plastic rim for viewing the corneal image. (C) and (D) Metal disc with concetric rings, one with wooden handle and one with metal handle. Both missing viewing lens.
Historical Significance: The placido disc is used to assess corneal regularity. It was devised by Portuguese ophthalmologist Antonio Placido in 1880 and was used in ophthalmic practice until the advent of corneal topographers in the 1990s. Keratometers only measure cornea at the apex of the cornea and provide no or littel nformation about surface irregularity of other parts of the cornea.
Location: Archive room. West wall. Unit 6 Drawer 4