Pupillary Distance (PD) Rule

Catalogue Number: 3520
Pupillary Distance (PD) Rule
Category: Equipment
Sub-Category: PD ruler, pupillometer
Year Of Publication/Manufacture: c 1920
Time Period: 1900 to 1939
Publisher/Manufacturer: Arthur Cocks and Co. Ltd.
Description Of Item: White ivorine rule 132 mm x 48 mm x 2 mm imprinted Arthur Cocks and Co. Ltd. Sydney, Melbourne, Brisbane, Adelaide & Wellington, N.Z., Scales in inches and centimetres and angles in 5 degree steps to 20 degrees on one face, an oval with 0 to 180 degree markings, Place right side of left here and a scale to measure frame width in inches and millimetres, scales above and below centre in inches and millimetres and a scale marked Lines (9 lines = 2 cm) on the other face.
Historical Significance: Arthur Cocks and Co. Ltd. was an optical and jewellery wholesale firm set up by Arthur Cocks in Sydney in 1899. By 1914 it had branches in Melbourne, Brisbane, Adelaide and Wellington. This rule would have been supplied to optometrists as a promotional item. It is of interest due to the scales being in both metric and imperial units suggesting the transition towards the use of metric units in optometry.
Condition: Good. Material yellowed
Location: Archive office. East wall shelves unit 3. Drawer 10

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