New visual acuity test for pre-school children.

A new test chart was developed for the measurement of visual acuity of pre-school children. The symbols of the test are circle, square, apple and house. These were so designed that each symbol measures visual acuity similarly. This feature of the test was verified experimentally. The visual acuity values measured by the individual symbols correlated highly with the visual acuity values measured with the whole test (0.82-0.86). The correlation between the visual acuity values measured repeatedly, the reliability of the new test, was found to be 0.94 for adult subjects. The new visual acuity test thus fulfils the statistical criteria of a good visual acuity test. Because both children and nurses seem to like the new test, it may be useful in the assessment of visual acuity in pre-school children.