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Characteristics and impact of nystagmus on visual acuity and eye movements in children with and without Down’s syndrome

Ahmad Zahidi, Asma A. 2019. Characteristics and impact of nystagmus on visual acuity and eye movements in children with and without Down’s syndrome. PhD Thesis, Cardiff University.
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Nystagmus, an involuntary oscillation of the eye, is one of the most common visual impairments occurring in individuals with Down’s syndrome, affecting between 15-30% of that population. In the typical population, nystagmus affects 0.02% of children. Due to the frequent occurrence of nystagmus in Down’s syndrome, nystagmus often appears to be assumed to be part of the condition and overlooked in this population of children. This study was designed to determine whether nystagmus is, in fact, the same or a different condition in children with and without Down’s syndrome. First, we investigated the visual characteristics of children with Down’s syndrome with and without nystagmus, by retrospectively reviewing clinical records of 198 children in the Down’s Syndrome Vision Research Unit cohort between 1992 and 2016. To compare the characteristics of nystagmus waveforms and the visual characteristics, we then conducted optometric assessments and recorded eye movements on 28 children with Down’s syndrome and 17 typically developing children with nystagmus. Further to this, we recorded the eye movements of both groups of children with nystagmus along with 20 children with Down’s syndrome and 20 typical children with no nystagmus while fixating on a stationary and a moving target. The aim was to characterize and compare the accuracy and precision of eye movements during fixation and when following a moving target for each group of children. The findings from this study suggest that nystagmus in children with Down’s syndrome is not a different condition from nystagmus in typically developing children. In addition, nystagmus has similar effects on visual acuity and eye movement performance in both groups of children with nystagmus. Therefore, children with Down’s syndrome and nystagmus should receive the same level of attention from health and education services that typical children with nystagmus do.

Item Type: Thesis (PhD)
Date Type: Completion
Status: Unpublished
Schools: Optometry and Vision Sciences
Subjects: R Medicine > RE Ophthalmology
Uncontrolled Keywords: Down's syndrome, visual acuity, smooth pursuit, fixation
Funders: Malaysian Government
Date of First Compliant Deposit: 30 September 2019
Last Modified: 29 Mar 2021 09:20

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