A recent study examined amblyopia’s impact on children’s ability to perform higher-order visual processing with executive function demands in order to gain a better understanding of visual pathway deficits in everyday function. The researchers found that children with amblyopia have significant visual processing deficits.

The study included 20 children with amblyopia (mean age: nine) and 20 children with normal vision development (mean age: 9.5). Of the 20 amblyopic children, 15 were anisometropic and five were strabismic. The children underwent vision assessment for monocular and binocular visual acuity and binocular function with the Worth 4-Dot test and Randot Preschool Stereotest. The researchers assessed the childrens’ visual attention and processing speeds with three “useful field of view” (UFOV) subtests. They measured their binocular visuo-cognitive search abilities with static and dynamic presentations of trail-making tests (TMTs).

The researchers noted the following results:

• Amblyopic children demonstrated slower visual processing times and completion times on the UFOV and TMTs, respectively, compared with children with normal eye development.
• Amblyopic childrens’ performance on the TMTs was significantly more negatively impacted with increasing executive function demands of TMT part B compared with controls.
• Binocular visual acuity was associated with UFOV and TMT performance.
• No other visual function measures were related to performance on the two tests.

 “Our findings of reduced binocular visual attention and search performance in children with amblyopia for more cognitively demanding tasks suggests that the negative effects of amblyopia may be exacerbated when undertaking more complex visually directed everyday activities,” the researchers wrote in their paper. “This adds to the growing literature on the binocular performance deficits of children with amblyopia, such as reading, writing and manual dexterity tasks, particularly when these performance measures are timed.”

The researchers reported additional deficits in hyperopic children aged six to seven, regardless of correction use, including spatial cognition, visuomotor coordination and visual motion and stereo processing—all functions associated with the dorsal stream. “A broad vulnerability in the dorsal stream of the visual pathway has been proposed to underlie the global motion, visuo-motor and additional deficits that underpin visual control of actions,” they wrote.

The researchers concluded, “Children with amblyopia exhibit deficits in higher-order visual processing skills, including visual attention and visual search, particularly with increasing executive function demands. These findings have implications for understanding the impact of amblyopia on everyday function in children.”