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Preferential looking is the technique of choice for measuring visual acuity in infants and young children. Most workers agree that the toddler age group, 1 to 3 years, is the most difficult to test. This is because of their short attention span and restlessness, but mostly because they find the grating target used in the test, frankly boring. The concept of the vanishing optotype chart offers alternative test targets, while utilizing the technique of preferential looking. We have designed a test which comprises a familiar shape (house, car etc.) on the upper or lower part of a neutral grey card. The shape is computer generated, and designed to fade completely when beyond the resolution limit. Acuity is determined by the width of the white lines making up the shape. As with conventional preferential looking, the observer notes the child's eye movements to determine the position of the target shape. Although picture naming is not required, the shapes help to maintain the child's interest in the test. The test is quick, and is successful with the toddler age group and older patients with intellectual impairment.

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We have developed a new contrast sensitivity (CS) test (similar in design to the Cardiff Acuity test) for use with children aged from 1‐3 years. It consists of a set of 42 multi‐orientational pictures all of one target size (car, boat, fish, house, train and duck) at 14 contrast levels (3 cards at each level). Results from tests performed on 23 adults (aged from 15–44 years) gave contrast sensitivity measurements in agreement with measurements made using the Pelli‐Robson Letter Chart. We tested 138 visually normal children (between 12–66 months) monocularly and binocularly to establish norms. The results from the children indicate that CS increases up to approximately 2 years of age after which it attains adult values. These results suggest that the Cardiff Contrast Test provides an effective measurement technique for the determination of contrast sensitivity in infants.

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