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Photorefraction of normal and astigmatic infants during viewing of patterned stimuli
Vision Research
|January 1, 1983
Insights
Infants
Area of Science:
- Ophthalmology
- Developmental Neuroscience
Background:
- Assessing visual development in infants is crucial for early detection of potential issues.
- Accommodation, the eye's ability to focus on near objects, is a key aspect of visual development.
Purpose of the Study:
- To investigate the accommodative responses of 3-month-old infants with and without astigmatism.
- To determine if astigmatism affects how infants adjust focus to different visual stimuli.
Main Methods:
- Photorefraction was employed to measure the accommodative state of infants.
- Infants viewed visual stimuli, including gratings of varying orientations and a cross pattern, at a fixed distance.
- Stimuli were presented using an apparatus designed for infant visual acuity testing.
Main Results:
- Most infants demonstrated appropriate accommodation for a vertical grating stimulus.
- Infants with astigmatism showed a lack of accommodative adjustment when stimulus orientation changed from vertical to horizontal.
- This suggests astigmatism may impair orientation-dependent focusing in early infancy.
Conclusions:
- Infant accommodation is generally appropriate for simple visual targets.
- Astigmatism appears to interfere with the ability of 3-month-old infants to adjust focus based on stimulus orientation.
- These findings highlight the impact of astigmatism on developing visual systems.
Abstract:
Photorefraction was used to assess the state of accommodation of 3-month old infants with and without astigmatism while they viewed stimuli in an apparatus commonly used to test infant visual acuity. The stimuli were a 1.6 c/deg vertical grating, a 1.6 c/deg horizontal grating and a cross composed of orthogonal 19 min lines, which were presented 55 cm from the infants. Most infants' accommodation was appropriate for the vertical grating. Astigmatic infants did not change their focus when the orientation of the grating was changed.