Scotopic optokinetic nystagmus thresholds in 10-week-old infants.
OBJECTIVE
To compare psychophysical and reflexive optokinetic nystagmus (OKN) estimates of dark-adapted scotopic thresholds mediated by the posterior retina in 10-week-old infants and adults.


METHODS
A staircase procedure was used to determine the stimulus intensity needed to produce an OKN response to a moving 19 degrees x 19 degrees grating. In the same subjects, a two-alternative, forced-choice procedure was used to obtain thresholds for detecting 10 degrees diameter, 50 ms duration stimuli.


RESULTS
Both OKN and psychophysical thresholds of infants are 0.9 log unit higher than those of adults.


CONCLUSIONS
The infant-adult difference in thresholds mediated by retina at the posterior pole is greater than the infant-adult difference in thresholds for full-field stimuli. It is possible that delayed maturation of the posterior retina is the primary determinant of infants' high OKN and psychophysical thresholds.
Hansen
R M
RM
Department of Ophthalmology, Children's Hospital, Boston, MA 02115.
Fulton
A B
AB
D000293:Adolescent; D000328:Adult; D003623:Dark Adaptation; D006801:Humans; D007223:Infant; D017120:Nystagmus, Optokinetic / Q000502:physiology*; D011601:Psychophysics; D012160:Retina / Q000502:physiology; D012684:Sensory Thresholds / Q000502:physiology*