Spatial visual acuity using FPCL methods is approximately what Snellen value by 1 year of age?

• A. 20/600
• B. 20/200
• C. 20/50
• D. 20/20

Answer: (C)

Infants’ spatial visual acuity improves rapidly in the first year, and FPCL testing estimates how well a baby can resolve patterns by watching where they look. In forced-choice preferential-looking, the examiner shows two intervals, one with a pattern and one without, and the infant’s tendency to look at the patterned interval indicates detection. The smallest pattern the infant reliably detects sets the measured acuity. By about one year, spatial acuity measured with FPCL is typically around 20/50. This reflects the ongoing maturation of the visual system: much poorer at birth, improving toward mid-level acuity by the end of the first year. Values like 20/600 or 20/200 are far below what’s expected at one year, while 20/20 is not yet typical at this age.