This study used the swept spatial-frequency method
to compare retinal and cortical acuity in anesthetized
young adult rhesus monkeys. Visual evoked potentials (VEPs)
and pattern electroretinographic responses (PERGs) were
recorded from 25 monkeys (age range: 4–12 years)
anesthetized with a continuous infusion of propofol. The
stimuli were temporally countermodulated sine-wave gratings
that increased in spatial frequency within a 10.24-s period.
All animals were refracted using acuity estimated from
the zero micro-volt intercept of the linear regression
of evoked potential amplitude on spatial frequency. Average
sweep acuities were 23.7 cycles/deg ± 1.5 S.E.M.
and 23.1 cycles/deg ± 1.8 S.E.M. for the PERG and
VEP, respectively. VEP and PERG acuities were within the
range expected based on acuities estimated from behavioral
studies in macaques. PERG and VEP acuities were highly
correlated (r = 0.90) and equally sensitive to
spherical blur. On a subset of animals, test–retest
reliability of animals, and interocular correlations, were
high (r = 0.87 and r = 0.83, respectively).
Increasing propofol dosage 8-fold did not degrade PERG
or VEP acuity. This study demonstrates that high spatial-frequency
acuities can be rapidly obtained from young adult rhesus
monkeys under a wide dose range of propofol anesthesia
using the swept spatial-frequency method.