Rats have become a popular model for investigating the mechanisms underlyin
g ocular dominance plasticity; however, no quantitative assessment of the e
ffects of visual deprivation on behavioural acuity has been reported in thi
s species. We measured the spatial acuity of monocularly and binocularly de
prived rats with a visual discrimination task. The average spatial acuity o
f normal rats and rats deprived of vision after postnatal day 40 was approx
imate to 1 cycle/degree. Monocular deprivation up to postnatal day 40 resul
ted in a 30% decrease in acuity and there was no recovery after 8 months. I
dentical binocular deprivation produced a comparable but significantly smal
ler reduction in acuity. The deleterious effects of monocular and binocular
deprivation on visual acuity indicate that the development of cortical rec
eptive field properties related to spatial tuning are affected by both mono
cular and binocular deprivation. The similarities in the effects of visual
deprivation on visual acuity between rats and other mammals confirm that ra
ts are a good model system for studying the cellular and molecular mechanis
ms underlying experience-dependent visual plasticity.