Postural stability in young adults with low-degree refractive errors: A prospective observational study

ObjectiveTo investigate whether uncorrected low-degree refractive errors are associated with alterations in postural stability in young adults using the Biodex Balance System.MethodsThis prospective observational study included 71 young adults classified into three groups: (a) emmetropia (n = 23); (b) low-degree myopia (n = 20); and (c) low-degree astigmatism (n = 28). The emmetropic group served as the comparison group. Postural stability was evaluated using the Biodex Balance System under four testing conditions: (a) eyes open-firm surface; (b) eyes closed-firm surface; (c) eyes open-foam surface; and (d) eyes closed-foam surface. Primary outcomes included the overall stability index and central stability percentage. Secondary outcomes included sway velocity and sway index measurements.ResultsParticipants with low-degree astigmatism demonstrated significantly higher instability and lower central stability compared with the emmetropic and low-myopia groups (both p < 0.001). In unadjusted comparisons, there were no significant differences in the overall stability index or central stability percentage between the low-myopia and emmetropia groups (p = 0.717 and 0.166, respectively). Adjustment for age, sex, and body mass index confirmed significant overall refractive-group effects for both primary outcomes (both p < 0.001). Sway velocity and sway index values were significantly higher in the low-myopia group during eyes-open tasks, particularly in the eyes open-firm surface and eyes open-foam surface conditions (p = 0.001 and p = 0.002, respectively). No significant between-group differences were observed during eyes-closed assessments.ConclusionsUncorrected low-degree refractive errors were associated with measurable differences in postural stability, particularly under conditions relying on visual feedback. Low-degree astigmatism was associated with reduced overall stability, whereas low-degree myopia was associated with greater sway during visually guided tasks. These findings suggest that even mild refractive changes may have functional implications for balance performance in young adults.