University College London

Moorfields Eye Hospital Nhs Trust

Ian E Murdoch

D Allstair Laidlaw

Dan A Rosser

Fred W Fitzke

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.

Growing community of inventors

Bucks, United Kingdom

Ian E Murdoch