Visuo-Cognitive Executive Functions in Amblyopia and Strabismus: Associations With Function and Quality of Life

Abstract

Purpose: The purpose of this study was to evaluate higher-order visual processing and executive function in adults with amblyopia and/or strabismus under habitual binocular viewing conditions and to explore their association with functional capabilities and vision-related quality of life (VRQOL).

Methods: This study included 114 adults (23 with amblyopia, 52 with amblyopia and strabismus, 20 with strabismus, and 19 healthy controls). Assessments included visual acuity and binocular function score (BFS), visuo-cognitive tests (Useful Field of View [UFOV], Trail Making Test [TMT], and Stroop Color and Word Test [SCWT]), and functional tests (fine motor skills [FMS] and reading rate). Group differences were evaluated using ANOVA, and regression models assessed the contribution of clinical and cognitive measures to functional outcomes and VRQOL.

Results: Performance significantly varied across groups (F(3,108) = 753, P < 0.001), for all three visuo-cognitive tests (UFOV F(3,108) = 2.982, P = 0.034; TMT F(3,108) = 5.289, P = 0.002; and SCWT F(3,108) = 4.068, P = 0.009). Adults with amblyopia and/or strabismus had significantly slower completion times on UFOV, TMT, and SCWT compared with healthy controls (P < 0.05), with pronounced deficits in divided attention, visual search, and cognitive flexibility. Performance among the three visuo-cognitive tests was strongly correlated (r's³ = 0.7, P = 0.01). Regression analyses revealed that SCWT times significantly predicted FMS and reading speed, explaining 42% and 31% of the variance, respectively. Psychosocial VRQOL scores were significantly influenced by the presence of strabismus (P = 0.001), whereas functional impact scores were associated with BFS (P = 0.04) and UFOV times (P = 0.02).

Conclusions: Amblyopia and/or strabismus in adults are associated with executive function deficits, poorer functional performance, and reduced VRQOL. These findings highlight the long-term visuo-cognitive and functional consequences of abnormal visual development and underscore the need for targeted interventions.

Figure 1.

Individual participant (circles) and group mean (error bars = ± SD) minimal display time to enable completion of the UFOV subtests, that is, visual processing speed for (a) central processing, (b) divided attention, and (c) selective attention. The Y-axis scales have been varied between sub-parts of the figure. UFOV total summed time is also displayed (d). Groups are amblyopia without strabismus (A, red), amblyopia with strabismus (AS, blue), strabismus without amblyopia (S, green), and control (C, purple). The P values report significance of least significant difference (LSD) post hoc tests between subgroups.

Figure 2.

Individual participant (circles) and group mean (error bars = ± SD) times to complete the TMT tests (a) TMT-A static, (b) TMT-B static, (c) TMT-A dynamic, (d) TMT-B dynamic, and (e) TMT total time (sum of all TMT tests). Groups are amblyopia without strabismus (A, red), amblyopia with strabismus (AS, blue), strabismus without amblyopia (S, green), and control (C, purple). The P values report significance of least significant difference (LSD) post hoc tests between subgroups.

Figure 3.

Individual participant (circles) and group mean (error bars = ± SD) time taken to complete the SCWT; (a) OFF time, (b) ON time, (c) OFF time + ON time, and (d) ON time + OFF time. Groups are amblyopia without strabismus (A, red), amblyopia with strabismus (AS, blue), strabismus without amblyopia (S, green), and control (C, purple). The P values report significance of least significant difference (LSD) post hoc tests between subgroups.