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Behavioural and electrophysiological measures of visual functions in children with neurological disorders
Insights
Assessing visual functions in children with neurological disorders revealed that visual acuity and visual field size were often impaired. These deficits were not always predictable from their neurological or ophthalmological conditions.
Area of Science:
- Ophthalmology
- Pediatrics
- Neurology
Background:
- Assessing visual function in children with neurological disorders presents unique challenges.
- Early detection of visual impairments is crucial for timely intervention and management.
Purpose of the Study:
- To evaluate visual functions, including acuity and visual field size, in children with neurological disorders.
- To determine the correlation between neurological/ophthalmological conditions and observed visual deficits.
Main Methods:
- Utilized preferential looking (PL) technique for visual acuity assessment.
- Employed pattern visual evoked potentials (VEPs) and simple visual field testing.
- Tested 37 children aged 10 weeks to 15 years with neurological disorders.
Main Results:
- Preferential looking acuity was obtained in 70% of tested patients, often lower than normal.
- Visual field defects were present in 21/23 children, with unpredictable links to underlying conditions.
- Pattern VEP acuity was significantly lower than PL acuity in some cases, potentially due to eye movements.
Conclusions:
- Visual functions, particularly acuity and visual fields, are frequently compromised in children with neurological disorders.
- Visual deficits are not consistently explained by known neurological or ophthalmological factors.
- A simplified perimeter is effective for visual field assessment in children aged 4+.
Abstract:
The preferential looking (PL) technique, pattern visual evoked potentials (VEPs) and (simple) tests for visual field size were used to assess visual functions in 37 children with neurological disorders, ranging in age from 10 weeks to 15 years. PL acuities were obtained for 23 out of 32 patients tested (70%). Acuity was nearly always lower than normal, which often, but not always, was related to ophthalmological or neurological defects. Pattern VEPs were recorded in 7 patients. In 3 out of 4 patients, VEP 'acuity' was much lower than PL acuity, possibly due to spontaneous eye movements. One of two cortically blind children had positive pattern VEPs. Visual field defects were seen in 21 out of 23 children tested with a simple method using a pair of white balls. In only one-third of these, the field defects could have been predicted by the neurological and/or ophthalmological conditions. In several cases, field size appeared to be affected by spontaneous and/or latent nystagmus. A simplified perimeter has been found very useful with children from the age of 4 years onwards.