In most clinical settings, the eye care practitioner makes a qualitative assessment of an infant's vision, based on his or her ability to show steady fixation of a target and to follow the target using smooth pursuit movements. However, the ability to fix and follow does not necessarily indicate normal visual acuity, since many older children with 20/200 or worse visual acuity fix and follow well (Day, 1990). Similarly, failure to show normal fixation and following shortly after birth is not necessarily predictive of a later visual deficit but may simply be an indicator of delayed visual maturation (Fielder et al., 1985; Illingworth, 1961).