Prevalence of ocular abnormalities in adults with Down syndrome in Hong Kong

Abstract

Background/aims This was a cross-sectional survey to find the prevalence of visual impairment and eye diseases among adults with Down syndrome (DS) in Hong Kong. Methods 91 DS patients over the age of 30 were recruited through the Hong Kong Down Syndrome Association. Each patient was provided with a complete ophthalmological assessment including best corrected visual acuity, refraction, slit lamp and fundus examination. Results In our sample, 56.6% had normal vision to mild vision impairment, 33.7% and 7.2% had moderate and severe vision impairment, respectively, and 2.4% were blind. The mean presenting distant LogMAR visual acuity was 0.66 (Snellen equivalent 20/90), and the best corrected LogMAR visual acuity was 0.48 (Snellen equivalent 20/60). Significant refractive errors were found in 86.3% of the eyes, with spherical equivalent corrections ranging from −23.25D to +3.00D. Myopia and astigmatism were prevalent and found in 59.3% and 72.7% of the eyes, respectively. Blepharitis and chalazion were found in 44% of the eyes, while corneal problems were present in 27.5%. There were low incidences of infective keratitis (0.5%), keratoconus (0.5%) and Brushfield spots (1.1%). Cataracts were found in 72.2% of the eyes; 26.1% were congenital and 44.9% were age-related. Fundal abnormalities were present in 49.5% of the eyes. Conclusions There is a high prevalence of vision impairment among Chinese DS adults. Uncorrected refractive errors, high myopia and cataracts are the main visually debilitating ophthalmological abnormalities. Vision may be improved through the simple use of glasses and early treatment of age-related cataracts.

The challenges of providing eye care for adults with intellectual disabilities

“…The study did not find a correlation between the magnitude of refractive error and the severity of intellectual disability. Similarly, Fong and colleagues found a range of spherical equivalent refractive errors from ‐23.25 to +3.00 D in patients with DS, with 59 per cent of DS participants being myopic with an average spherical refractive error of ‐5.75 ± 4.6 D. Significant astigmatism (defined as 1.00 D or more) was found in 72 per cent of patients, with the average value being 2.06 ± 1.1 DC; however, Fong and colleagues’ study was carried out on Chinese patients with DS, which does not represent the global prevalence. The prevalence of myopia in patients with intellectual disabilities varied between 18 and 33 per cent among other populations .…”

“…The prevalence of significant refractive error found in patients with intellectual disabilities and the rate of spectacle prescribing is not in a linear relationship. Studies have shown lower spectacle prescription rates for people who were institutionalised (24 per cent) compared to those who lived at home (45 per cent) and yet more significant refractive errors were found in those living in institutions . McCulloch and colleagues demonstrated that more spectacles were prescribed for patients with mild intellectual disabilities and prescribing rates dropped in groups with more severe intellectual disabilities.…”

Cataract surgery outcomes in adult patients with Down's syndrome: Table 1

“…The incidence of Down's syndrome in Hong Kong is 1.28 per 1000 live births,19 which is slightly higher than the 1.00 per 1000 live births reported in the USA 20. The incidence of age-related cataract in patients with Down's syndrome has been shown to be as high as 35–50% 8 21 22. The occurrence of early cataract has been attributed to multiple factors such as susceptibility to oxidative stress23 and accumulation of amyloid precursor protein and amyloid-β peptides24 25 in the lens.…”

“…Of these, refractive errors and cataract should be corrected at the earliest in order to avoid preventable ocular morbidity related to these disorders. A recent study from Hong Kong revealed the incidence of refractive errors and cataracts in adult patients with Down's syndrome to be 86.3% and 72.2%, respectively 8. The authors suggested that uncorrected refractive errors and cataracts are the main visually debilitating ophthalmological abnormalities in this group of patients 8.…”

“…A recent study from Hong Kong revealed the incidence of refractive errors and cataracts in adult patients with Down's syndrome to be 86.3% and 72.2%, respectively 8. The authors suggested that uncorrected refractive errors and cataracts are the main visually debilitating ophthalmological abnormalities in this group of patients 8. However, not all patients with Down's syndrome may receive a regular and timely ophthalmological assessment.…”