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Refractive development in children with Down's syndrome: a population based, longitudinal study
O H Haugen1, G Høvding, I Lundström
1Department of Ophthalmology, Haukeland University Hospital, Bergen, Norway. ohha@haukeland.no
Insights
Children with Down syndrome often have refractive errors. Stable, low hypermetropia was linked to normal accommodation, while accommodation weakness may contribute to vision problems in this population.
Area of Science:
- Ophthalmology
- Genetics
- Developmental Biology
Background:
- Down syndrome is associated with a high prevalence of refractive errors, including hypermetropia and astigmatism.
- Understanding the longitudinal refractive development in children with Down syndrome is crucial for early intervention and management.
Purpose of the Study:
- To longitudinally investigate refractive development in children with Down syndrome.
- To identify correlations between refractive status, accommodation, and astigmatism in this population.
Main Methods:
- A cohort of 60 children with Down syndrome underwent repeated retinoscopies under cycloplegia for over two years.
- Accommodation was assessed using dynamic retinoscopy.
- Refractive categories included stable hypermetropia, increasing hypermetropia (hypermetropic shift), and decreasing hypermetropia/myopic shift.
Main Results:
- Three refractive categories were observed: stable hypermetropia (n=34), increasing hypermetropia (n=11), and decreasing hypermetropia/myopic shift (n=9).
- Accommodation weakness was present in 55% of children and was less frequent in stable, low-grade hypermetropia.
- Astigmatism (>/=1.0 D) was found in 57% of eyes, predominantly with-the-rule, and oblique astigmatism showed specific axis directions for right and left eyes.
Conclusions:
- Stable, low-grade hypermetropia in children with Down syndrome is significantly correlated with normal accommodation.
- Accommodation weakness may play an etiological role in the high frequency of refractive errors observed.
- The specific axis direction in oblique astigmatism suggests mechanical factors related to palpebral fissures may contribute to its development.
Aims:
To study the refractive development in children with Down's syndrome longitudinally.
Methods:
An unselected population of 60 children with Down's syndrome was followed with repeated retinoscopies in cycloplegia for 2 years or more (follow up 55 (SD 23) months). Accommodation was assessed with dynamic retinoscopy.
Results:
From longitudinal spherical equivalent values of the right eye, three main categories of refraction were defined: stable hypermetropia (<1.5 D difference between the first and last visit) (n=34), increasing hypermetropia ("hypermetropic shift"; >/=1.5 D difference) (n=11), and decreasing hypermetropia/development of myopia ("myopic shift"; >/=1.5 D difference) (n=9). Patients with anisometropia (n=6) were evaluated separately. In the stable hypermetropia group three sublevels were chosen: low (+4.0 D). An accommodation weakness was found in 55% of the children. Accommodation weakness was significantly less frequent in the stable, low grade hypermetropia group (22%) than in all the other groups (p=0.008). The frequency of astigmatism >/=1.0 D at the last visit was 57%, the direction of axis being predominantly "with the rule." All the eyes with oblique astigmatism had a side specific direction of axis; the right eyes belonging to the 135 degrees axis group and the left eyes to the 45 degrees axis group.
Conclusion:
A stable, low grade hypermetropia was significantly correlated with a normal accommodation. Accommodation weakness may be of aetiological importance to the high frequency of refractive errors encountered in patients with Down's syndrome. A striking right-left specificity in the oblique astigmatic eyes suggests that mechanical factors on the cornea from the upward slanting palpebral fissures may be a major aetiological factor in the astigmatism.