Snellen letter visual acuity chart in a Germanic (Fraktur?) font
 Catalogue Number: 3363 Snellen letter visual acuity chart in a Germanic (Fraktur?) font Category: Equipment Sub-Category: Visual Acuity, Contrast sensitivity tests Year Of Publication/Manufacture: c 1900 Time Period: 1900 to 1939 Description Of Item: Snellen letter visual acuity chart printed on paper, 238 x 580 mm, with four folds, in a Germanic font (Fraktur?), with letter sizes ranging from 6/36 to 6/6, with each letter contained within a faint grey 5 x 4 grid to show that that the letter height, width and limb width conform to one of Snellen's principles for a standard visual acuity chart. The size of the letters in each line is shown in grey print in the format D = 8. where the number is the denominator in the usual Snellen notation (e.g 6/6) and is the distance at which the height of the letters subtends 5 min of arc. At the bottom of the chart are the words 'H. SNELLEN, Optotypi: tabula VII Historical Significance: This item was found tipped into Eduard Jaeger's Schrift-skalen (Reading scales) near point reading card 10th edition 1909 (Cat no. 270) along with several other loose items, which remain in the Jaeger booklet. This Snellen chart may have been part of the Jaeger booklet but it is a booklet on reading scales not distance visual acuity charts and there is no indication that the VA chart is related. It may have been tipped in by a previous owner of the Jaeger booklet any time after 1909. The Snellen chart was first devised in 1862 (See Snellen monograph/ Test-types for the determination of the acuteness of vision. Utrecht: P.W. van de Weijer) and the archaic character of this item suggest a date of early 19th C or learly 20th C. Condition: Good Location: Archive office. Pamphlet and ephemera filing cabinet. Drawer 7 |