Abstract
Visual acuity measurement is a vital part of an optometric examination. The purpose of the present study was to compare visual acuity in preschool children using two charts – the Lea symbols chart and the Sheridan Gardiner chart. One hundred and fifty-three preschool children (72 boys and 81 girls) between the ages of 3 and 5 years (mean age and standard deviation 4.23 ± 0.78 years) were recruited from five randomly selected nursery schools. Distance visual acuity was measured monocularly and binocularly after a pre-test was done. An interval of 5 minutes was allowed for testing with both charts. The ages and sexes of each child were documented. Results showed a statistical difference in visual acuities using both charts (p < 0.05). There was also a statistical difference in both charts regarding age. There was no significant gender difference between the results from each chart.
Highlights
Vision is the appreciation of differences in the external world, such as form, colour and position, resulting from stimulation of the retina by light, whilst acuity is the capacity for seeing distinctly the details of an object.[1]
Measurement of visual acuity can be done by detection acuity, resolution acuity or recognition acuity
The purpose of the study was to determine whether there was a difference in preschool children in Visual acuity (VA) measurements between the Lea symbol chart and the Sheridan Gardiner chart
Summary
Vision is the appreciation of differences in the external world, such as form, colour and position, resulting from stimulation of the retina by light, whilst acuity is the capacity for seeing distinctly the details of an object.[1]. Resolution acuity is the ability to resolve the critical element of a stimulus pattern such as the orientation of the gap in a Landolt C optotype or the direction of the limbs in a Tumbling E.4,5. Recognition acuity is the ability to identify a particular object. Recognition acuity is determined by the smallest optotype that can be identified by the observer. Numbers or symbols.[3] There are several notations by which VA can be represented. They include the Snellen fraction, decimal notation, minimum angle of resolution (MAR) and logarithm of minimum angle of resolution (logMAR). Several notations can be used including M or N notation, reduced Snellen notation, and point or Jaeger notation
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