The Assessment of Visual Acuity by the Forced Preferential Looking Method

Glen A. Gole
Prudence A Hall

Forced choice preferential looking (FPL) is a behavioural method for the assessment of visual acuity in preverbal infants. Using apparatus, designed and built locally, we tested 63 babies whose ages ranged from 6 weeks to 11 months on photographically generated grating targets. We could measure binocular acuity in 51 (81%). Our results show a progressive improvement in visual acuity until approximately 6 months of age. Our results in a small number of babies older than 6 months indicate the standard FPL technique is unreliable in older babies due to inattention.