Fine visuomotor skills in amblyopia: a systematic review and meta-analysis

BACKGROUND: Amblyopia is characterised by reduced visual acuity, poor binocular sensory fusion, and impaired or absent stereoacuity. Understanding the extent to which amblyopia affects everyday task performance is important to quantifying the disease burden of amblyopia and can assist clinicians to understand patients' likely functional capability. METHODS: A systematic literature search identified published studies comparing fine visuomotor performance in either children or adults with amblyopia and those with normal binocular vision. The included studies (22 studies involving 835 amblyopes and 561 controls) reported results of self-perception patient reported outcome measures, tests of motor proficiency and video recorded reaching and grasping. The outcomes of 17 studies were grouped into four meta-analyses, with pooled results reported as standardised mean difference (SMD) with corresponding 95% CI. RESULTS: Regardless of the cause of amblyopia (anisometropia, strabismus, mixed, deprivation), significant reduction in self-perception of physical competence and athletic competence (SMD=-0.74, 95% CI -1.23 to -0.25, p=0.003); fine motor skills scores (SMD=-0.86, 95% CI -1.27 to -0.45, p<0.0001); speed of visually guided reaching and grasping movements (SMD=0.86, 95% CI 0.65 to 1.08, p<0.00001); and precision of temporal eye-hand coordination (SMD=0.75, 95% CI 0.26 to 1.25, p=0.003) occurred in amblyopes compared with those with normal visual development. CONCLUSION: Reports of the impact of amblyopia on fine motor skills performance find poorer outcomes in participants with amblyopia compared with those with normal vision development. Consistency in the outcome measure used to assess the functional impact of amblyopia would be valuable for future studies.