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Editor,—Testing visual acuity in children can be difficult, largely because of their lack of knowledge of the alphabet. Their short attention span and poor cooperation also contribute.
The Sheridan–Gardiner method is a very useful and widely used for testing vision in children, especially preschool children and those with learning difficulty.
The examiner shows letters of different sizes (corresponding to different levels of Snellen acuity) from a distance of 6 metres, to a child who holds a card with the same letters. Older children will point to the letter and turn the card to show it to the examiner. In most instances, however, the help of a second person is needed. This person indicates to the examiner whether or not the child has pointed to the correct letter.
In our modification of the Sheridan–Gardiner test, the child is given a semitransparent card with a tinge of pink colour. The letters are in black and can easily be seen against the pink background. This enables the examiner to directly visualise the letters pointed to by the child obviating the need of a second person (Fig 1).
The modified card was validated by comparing the results of visual acuity testing in 30 children (5–7 years old) each, by two school nurses. One nurse held the test cards at 6 metres and the other sat beside the child. The conventional method was first used and vision recorded. The modified card was then given to the child and the test repeated. In another group of 30 children, the nurses reversed roles and again both the conventional and modified cards were used.
With the conventional method only three out of 30 in one group and four out of 30 in the other group could be tested without the second person's help. With the modified card, all children in each group could be tested easily and quickly without the second person's help.
In our opinion, use of the modified semitransparent card will improve the efficiency of testing vision in children.