The influence of manifest strabismus and stereoscopic vision on non-verbal abilities of visually impaired children.
Eye alignment type predicts which visuospatial tasks a visually impaired child will find easy or hard.
01Research in Context
What this study did
Gligorović et al. (2011) looked at how eye alignment and 3-D vision shape puzzle-solving skills in kids who are visually impaired. They sorted the children by eye condition: some had outward-turned eyes (divergent strabismus), some had inward-turned eyes (convergent strabismus), and some saw the world flat (no stereopsis).
Then they gave each child visuospatial subtests—tasks like copying shapes or remembering block patterns. No teaching or treatment happened; the team just wanted to see who scored best.
What they found
Kids with outward-turned eyes beat the other groups on most visuospatial tasks. The differences were statistically significant, meaning the pattern was unlikely due to chance.
Children who saw the world flat scored lowest, even lower than the inward-turn group. The authors note these are correlations only; they did not test any intervention.
How this fits with other research
Bathelt et al. (2019) extends these findings. They show that severe congenital visual impairment also drags down adaptive behavior and quality of life, adding real-world weight to Milica’s test scores.
Milne et al. (2009) seems to disagree at first glance. They found reduced convergence in kids with autism, implying inward-turn is the problem. The clash clears up when you notice the populations: Milica studied generic visual impairment, while Elizabeth looked at autism. Different diagnoses, different eye patterns.
Cardillo et al. (2022) used a similar method—visuospatial tasks to profile clinical kids—confirming that standardized drawing tests can reliably separate processing styles across diagnoses.
Why it matters
Before you teach spatial concepts, check the child’s eye report. Outward-turn? Use their intact 3-D skills for puzzles and maps. Flat vision? Break tasks into small, sequential steps and rely on verbal cues. Share the eye findings with the TVI so your lesson plans match the child’s visual strengths.
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02At a glance
03Original abstract
This research was conducted in order to examine the influence of manifest strabismus and stereoscopic vision on non-verbal abilities of visually impaired children aged between 7 and 15. The sample included 55 visually impaired children from the 1st to the 6th grade of elementary schools for visually impaired children in Belgrade. RANDOT stereotest and polaroid glasses were used for the examination of stereoscopic vision, while Cover test and Hirschberg's pupils reflex test were used for the evaluation of strabismus. In the area of non-verbal abilities was evaluated visual discrimination, visuomotor integration, constructive praxia, visual memory, strategy formation, non-verbal reasoning and the representational dimension of drawings. Subtests of ACADIA test of developmental abilities were used for the evaluation of non-verbal abilities (Atkinson et al., 1972). Statistically significant relations between strabismus and constructive praxia (p=0.009), visual memory (p=0.037), strategy formation (0.040) and the quality of drawings were determined by the results analysis. According to our findings, children with divergent strabismus achieve the best results. Children with stereoscopic vision generally achieve better results in all the examined areas of non-verbal abilities, and statistically significant relations were determined in the areas of visuomotor coordination (0.002), constructive praxia (0.026) and non-verbal reasoning (0.015), which are directly connected to visuospatial abilities. Children with convergent strabismus achieve significantly lower results in the areas of constructive praxia, visual memory, strategy formation and representational dimension of drawings, and children with the lack of stereoscopic vision--in the areas of visuomotor integration, constructive praxia and non-verbal reasoning.
Research in developmental disabilities, 2011 · doi:10.1016/j.ridd.2011.03.018