[500 visual acuity tests in infants with Teller acuity cards].

Assessment of visual resolution with Teller Acuity Cards is now routine procedure in infant visual check-up. A grating is printed on one end of a card on an homogeneous background of the same mean luminance. A series of spatial frequencies at an interval of one half octave covers the range of infant acuity. Binocular and monocular acuities have been measured on 517 infants between 100 and 399 days of age. The cards can be used from a few weeks of age up to 18 months at least. Then it gets more chancy to keep the child attentive. Binocular and two monocular tests take 6 minutes with a normal child. Binocular grating acuity normally reaches 6.5 cycles/degree at 4 months of age, and 12 c/deg at 12 months. Monocular acuity is one half octave lower. From the level of acuity obtained and observation of the behaviour, amblyopia can be detected and low vision can be estimated easily in infants.