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Assessment of visual acuity in children with trisomy 18
1Department of Ophthalmology, Loyola University Chicago, Maywood, IL 60153, USA.
Insights
Children with trisomy 18 (Edwards syndrome) demonstrate measurable, though significantly reduced, visual acuity. This study provides the first objective measurements of vision in these individuals, highlighting profound developmental delays.
Area of Science:
- Ophthalmology
- Genetics
- Developmental Pediatrics
Background:
- Trisomy 18 (Edwards syndrome) is a severe genetic disorder with high mortality.
- A small percentage of individuals with trisomy 18 survive past infancy, often with profound developmental delay.
- Ocular health is crucial for development, yet visual function in long-term survivors of trisomy 18 is poorly understood.
Purpose of the Study:
- To objectively measure visual acuity in children with trisomy 18.
- To characterize the visual capabilities of nonverbal individuals with profound developmental delay due to trisomy 18.
Main Methods:
- Five children with trisomy 18 (ages 6 months to 8 years) underwent comprehensive eye examinations.
- Binocular grating acuity was assessed using Teller acuity cards.
- Binocular vernier acuity was evaluated using vernier cards.
Main Results:
- All participants demonstrated measurable binocular grating acuity, ranging from 0.9 to 2.2 cycles per degree.
- This acuity was significantly reduced compared to age-matched norms, indicating a mean reduction of 3.5 octaves.
- No participant responded to any vernier acuity tests, even at the largest offset.
Conclusions:
- Children with trisomy 18 exhibit significantly impaired visual grating acuity, correlating with their profound developmental delay.
- The inability to perform vernier acuity tasks suggests deficits in higher-level visual processing.
- These findings underscore the importance of visual assessment in managing children with trisomy 18 and profound developmental delay.
Abstract:
Although 90% of children with trisomy 18 (Edwards syndrome) die in the first year of life, a small proportion survive into the second and third decade. Many do not have associated ocular abnormalities that might affect vision. Measurable visual acuity has not been reported in these profoundly developmentally delayed individuals. Five children with trisomy 18, aged six months to eight years, underwent complete eye examination including assessment of binocular grating acuity with Teller acuity cards and assessment of binocular vernier acuity with vernier cards. All children were nonverbal with profound developmental delay. Binocular grating acuity ranged from 0.9 cycles per degree (cpd) to 2.2 cpd. This represents a reduction of 1.9 to 5.1 octaves (mean 3.5 octaves, SD 1.3 octaves) compared to age matched norms. None of the children responded to any of the vernier offsets, including the largest of 64 minutes of arc. All children with trisomy 18 demonstrated a measurable grating acuity that was well below normal for age, consistent with profound developmental delay.
