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Published on: March 17, 2023
The influence of stimulus size on measured visual field extent in infants
Velma Dobson1, Meigan B Baldwin, Kathleen M Mohan
1Department of Ophthalmology, University of Arizona, Tucson 85711, USA. udobson@eyes.arizona.edu
Insights
Larger visual stimuli reveal greater visual field extent in infants but not adults. This finding in infant visual development may be due to differences in peripheral summation or attention.
Area of Science:
- Ophthalmology
- Developmental Neuroscience
- Visual Perception
Background:
- Assessing visual field extent in infants is crucial for understanding visual development.
- Standard perimetry methods may not be optimal for infant visual field testing.
Purpose of the Study:
- To compare measured visual field extent using a 6-degree stimulus versus a 1.5-degree stimulus in young infants.
- To determine if stimulus size affects visual field measurements in different age groups.
Main Methods:
- Kinetic perimetry was used with 120 infants (3.5 and 7 months) and 24 adults.
- Subjects were tested monocularly with either a 6-degree or 1.5-degree white stimulus.
- Visual field extent was measured by the stimulus's leading edge position during eye movements.
Main Results:
- A 6-degree stimulus yielded larger visual field extents than a 1.5-degree stimulus in 7-month-olds (nasal and temporal fields).
- A 6-degree stimulus showed larger extents in the temporal field for 3.5-month-olds.
- No significant difference in visual field extent was observed between stimulus sizes in adults.
Conclusions:
- Increasing stimulus size beyond 2 degrees enhances measured visual field extent in young infants, but not adults.
- Differences in peripheral summation or attentional factors may explain the observed age-related effects.
Purpose:
To compare measured visual field extent for a 6 degrees stimulus (typical size used in studies of infants) with a 1.5 degrees stimulus (similar to the largest size used in Goldmann perimetry) in young infants.
Methods:
A total of 120 infants (60 each at 3.5 months and 7 months of age) and 24 adults were tested monocularly with a kinetic perimetry procedure using a black double-arc perimeter. Each subject was tested with either a 6 degrees or 1.5 degrees white sphere, which was mounted on a black wand and moved smoothly toward the intersection of the perimeter arms at 3.4 degrees /s. Visual field extent along each perimeter arm was defined as the median of 2 to 3 measurements of the position of the leading edge of the stimulus when the subject made an eye movement toward the stimulus.
Results:
The 6 degrees stimulus produced larger measured visual field extent than the 1.5 degrees stimulus in 3.5-month olds (temporal field only) and in 7-month olds (nasal and temporal field), but not in adults.
Conclusions:
Using the testing conditions of the present study, increasing stimulus size beyond the largest used in a Goldmann perimeter (approximately 2 degrees) increases measured visual field extent in young infants, but not in adults. This may relate to differences in peripheral summation areas or to differences in attentional factors between infants and adults.
