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Contrast sensitivity in 24- and 36-month-olds as assessed with the contrast sensitivity card procedure
1Memorial University of Newfoundland, St. John's.
Insights
This study introduces a new card procedure to measure contrast sensitivity (CS) in young children. Toddlers showed reduced CS compared to adults, indicating potential for early visual dysfunction detection.
Area of Science:
- Ophthalmology
- Developmental Neuroscience
- Pediatric Optometry
Background:
- Assessing visual function in infants and toddlers is crucial for early detection of potential developmental issues.
- Contrast sensitivity (CS) is a key visual parameter that matures throughout early childhood.
- Existing methods for evaluating CS in very young children can be time-consuming and challenging.
Purpose of the Study:
- To introduce and validate a novel card-based procedure for assessing binocular contrast sensitivity in 24- and 36-month-old children.
- To compare the contrast sensitivity functions (CSF) of toddlers with those of adults.
- To evaluate the efficiency and potential clinical utility of the new CS cards.
Main Methods:
- A new set of 40 large matteboard cards with sine wave gratings at varying spatial frequencies and contrast levels was developed.
- A modified forced-choice preferential looking (FPL) technique, adapted from the Teller Acuity Cards (TAC), was employed.
- Binocular contrast sensitivity was measured in 24- and 36-month-old children, with testing time averaging 12 minutes per child.
Main Results:
- The CS card procedure was successfully completed by all 36-month-olds and 74% of 24-month-olds.
- The mean contrast sensitivity functions (CSF) for both age groups exhibited an inverted U-shape, similar to adults.
- Toddlers' CS functions were shifted towards lower contrast levels and lower spatial frequencies compared to adult norms.
Conclusions:
- The novel CS cards provide a time-efficient method for assessing contrast sensitivity in infants and young children.
- The findings suggest that the CS cards may serve as a prototype for a clinical tool to identify early visual and neurological impairments.
- The observed differences in CS between toddlers and adults highlight the ongoing visual development during early childhood.
Abstract:
We used a new card procedure to evaluate binocular contrast sensitivity (CS) in 24- and 36-month-old children. The test consists of 40 large (50 by 28 cm) matteboard cards, each of which contains a sine wave grafting with 1 of 5 spatial frequencies (0.4, 0.8, 1.6, 3.2, and 4.8 cpd at 80 cm) and with 1 of 8 contrast levels [from 33% (CS = 3) to 0.4% (CS = 260)]. Estimates of subjects' CS to each spatial frequency were obtained with a modified forced-choice preferential looking (FPL) technique similar to that developed for the Teller Acuity Cards (TAC). All 36-month-olds and 74% of the 24-month-olds completed the entire procedure in an average of 12 min per child. For both groups, the shape of the mean constant sensitivity functions (CSF's) resembled the characteristic inverted U shown by normal adults, except that the toddlers' functions were shifted to lower contrasts and spatial frequencies. Combined with previous results, it appears that the CS cards hold promise as a time-efficient means of assessing CS in infants and young children, and may provide the prototype for a clinical tool to help detect early visual and neurological dysfunction.