Spencer's ophthalmic test type Plate No 3 (Visual acuity chart)
 Catalogue Number: 2005 Spencer's ophthalmic test type Plate No 3 (Visual acuity chart) Category: Equipment Sub-Category: Visual Acuity, Contrast sensitivity tests Year Of Publication/Manufacture: Late 19th C Time Period: 19th C Place Of Publication/Manufacture: New York Publisher/Manufacturer: Spencer Optical Manufacturing Co Description Of Item: Printed card visual acuity chart, framed in a glass-fronted black bevel frame with timber backing behind, 270 mm W x 485 mm H. The card is headed 'Spencer's Ophthalmic test Type (Plate No 3), Spencer Optical Manufacturing Co, Established 1858. Salesrooms 15 Maiden Lane, New York USA'. It has 9 rows of serifed letters of diminishing size and increasing number, the largest letter at the topfrom the top. The letter sizes are designated with Roman numerals CC, C, LXX, L, XL, XXX, XX, XV, X. (that is 20/200, 20/100. 20/70, 20/50, 20/40, 20/30. 20/20. 20/15, 20/10). The letters are contained within a 5 x 5 grid except the largest letter A which is on a 6 x 5 grid. Historical Significance: The Spencer Optical Manufacturing Company was one of the early ophthalmic manufacturing laboratories in the USA. It was an existing company in 1858 when James E Spencer bought it from his retiring employers and then renamed it eponymously a few years later. It grew to a sizeable company by 1897 employing 2500 people. It made lenses, spectacle frames, magnifiers, binoculars and opera glasses. This VA chart is very similar to that devised by Snellen in 1862: like Snellen's chart it has serifed letters, the letters have been designed around a 5 x 5 grid and uses exactly the same sequence of letters and numbers that were in Snellen's original chart. The Company published a small booklet on 'Visual imperfections and test type.' written by CA Bucklin in 1881. Snellen had not devised his VA chart, on which this one is modelled until 1862. The fact that the company published a booklet on visual acuity in 1881, suggests this item dates from about that time. How Acquired: Donated by James Moran, Geelong optometrist Date Acquired: May 2005 Condition: Good except some water marks on bottom of chart Location: Archive room. North wall slat board |