Prevalence of strabismus among preschool children in eastern China and comparison at a 5-year interval: a population-based cross-sectional study

Abstract

ObjectiveTo update data on strabismus and evaluate the changes in prevalence and patterns among preschoolers in eastern China over a period of 5 years.DesignNanjing Eye Study, a longitudinal population-based study.SettingRecruitment and testing in kindergartens in Yuhuatai District, Nanjing.Participants2300 eligible children.Main outcome measuresComprehensive ocular examinations were conducted in 1986 children aged 48–<60 months in Nanjing Eye Study (NES, 2016–2017), including visual acuity, ocular alignment, refractive error and ocular structures evaluation. The prevalence rate and pattern of strabismus were calculated and compared with those from the Nanjing Pediatric Vision Project (NPVP, 2011–2012) in children of the same age, of the same area and using the same diagnostic criteria.ResultsThe overall prevalence rate of strabismus in NES was 5.56% (95% CI 4.54% to 6.57%), which was not significantly different from that in NPVP (4.99%, 95% CI 4.13% to 5.84%, p=0.40). The prevalence of subtypes of strabismus underwent significant changes, with significant increase in intermittent exotropia (IXT) in NES (2.78% vs 4.69%, p=0.001) and significant decrease in constant exotropia (1.17% vs 0.15%, p<0.001). Significant change in pattern was observed in IXT, where the proportion of the convergence insufficiency type (2.90% vs 27.17%) increased and exceeded the divergence excess type (20.29% vs 11.96%) to be the second common type (p<0.001).ConclusionThe prevalence of strabismus appeared stable in children aged 48–<60 months in eastern China at a 5-year interval. The prevalence of IXT increased significantly, and the convergence insufficiency type became more prevalent in patients with IXT. Timely detection and intervention of IXT are important among preschoolers.

Evaluation of Clinical Characteristics and Risk Factors of Strabismus Cases

“…Among the strabismus cases, those that were fixed at both near and far distances were considered as constant tropia, and those that were not fixed were considered as intermittent tropia. The strabismus cases were also classified according to the direction of the tropia as esotropic, exotropic, and vertical [ 14 ].…”

Diagnostic performance of the Spot vision photoscreener for the detection of exodeviation in preschool‐aged children

“…Twice as many Singaporean children presented with exotropia than esotropia. Studies from Chinese and Japanese populations also reported the higher prevalence of exotropia compared with esotropia 16–18 …”

“…Studies from Chinese and Japanese populations also reported the higher prevalence of exotropia compared with esotropia. [16][17][18] With the use of a photoscreener in our department as a part of paediatric eye examinations, we noticed that it missed some children with significant exotropia. As photoscreeners are being used more widely by paediatricians, their diagnostic accuracy for strabismus must be evaluated, and the photoscreener guideline for children with ocular misalignment should be provided for paediatricians.…”

Multiple factors causing alignment instability in childhood concomitant strabismus

“…Childhood concomitant strabismus is the most common strabismus disorder, affecting up to 5.41% of Chinese children, [1] and it is associated with a signi cant negative impact on quality of life and a de cit in binocular vision. [2] It is often initially managed by prescription glasses and occlusion therapy, but when children nish amblyopia therapy and undergo alternate xation, extraocular muscle surgery is the next intervention therapy indicated.…”