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Design of an Arabic near visual acuity chart
Author(s) -
Oduntan Alabi O.,
AIAbdulmunem Mosa'ad A.
Publication year - 1997
Publication title -
ophthalmic and physiological optics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.147
H-Index - 66
eISSN - 1475-1313
pISSN - 0275-5408
DOI - 10.1046/j.1475-1313.1997.9600052x.x
Subject(s) - legibility , chart , visual acuity , row , optometry , arabic , luminance , mathematics , computer science , artificial intelligence , ophthalmology , medicine , statistics , art , linguistics , philosophy , database , visual arts
Summary This paper describes the design of an Arabic test chart for measurement of visual acuity at near. The chart was designed employing specially selected Arabic letters and was based on the logMAR principle devised by Bailey and Lovie, Ten Arabic letters of nearly equal legibility values (0.92–1.05) (mean = 1.00), (SD = 0.05) were used in the design of the chart. Each row of the chart has 5 letters and row legibility values range from 4.82 to 5.03 with a mean of 4.92 (SD = 0.06). The logMAR method of visual acuity scaling was used, hence the sizes of letters in the rows progress in a uniform step of 0.1 log unit. The inter letter spacing is equal to the width of each letter in the row, while inter–row spacing is equal to the height of letter in the subjacent row. The height of letters ranged from 3.67 to 0.46mm corresponding to visual acuity of 2.4 M to 0.3 M which is equivalent to reduced Snellen 6′36 to 6:4.5 at 0.4 m. The chart is designed for use at 40cm with a recommended luminance level of 160cd/m 2 .