Patents by Inventor Ian E. Murdoch

Ian E. Murdoch has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Reduced logMAR visual acuity test chart
    Patent number: 6142631
    Abstract: An improved visual acuity chart is disclosed. The ratio of the size of the optotypes of neighbouring lines on the chart is a constant and preferably the size decrement between lines is 0.1 logMAR. Each line of optotypes has two, three or four optotypes, preferably three. Crowding bars for visual acuity charts are also disclosed. These bars are spaced from the ends of row and/or above and below the top and bottom lines. The individual bars may be joined together with linking sections. The spacing form the optotypes is preferably one half the width or height of the optotypes and their breadth is preferably that of the strokes of the optotypes.
    Type: Grant
    Filed: January 22, 1999
    Date of Patent: November 7, 2000
    Assignees: University College London, Moorfields Eye Hospital NHS Trust
    Inventors: Ian E. Murdoch, D. Allstair H. Laidlaw, Dan A. Rosser, Fred W. Fitzke