تأثیر کاهش دید مرکزی بر تعادل و جابجایی در سالمندان: یک مرور نظام مند

Introduction

Visual information is a fundamental component of postural control and locomotion, particularly in older adults. Central vision loss (CVL), commonly caused by conditions such as age-related macular degeneration, leads to a reduction in high-acuity visual input while peripheral vision remains relatively intact. This visual impairment forces individuals to adopt compensatory strategies during mobility tasks. The present review aims to synthesize evidence regarding the effects of central vision loss on balance, gait, obstacle negotiation, and visually guided locomotion in older adults, with a focus on behavioral and biomechanical adaptations.

Methods

This review was conducted following PRISMA guidelines. A systematic literature search was performed in major scientific databases from inception to February 2026. Studies were included if they investigated older adults (≥60 years) with central vision loss or used simulation paradigms of central vision impairment in healthy participants. Eligible studies needed to report outcomes related to balance, gait, obstacle avoidance, visually guided walking, or eye movement behavior during locomotion tasks. Due to methodological heterogeneity, findings were synthesized qualitatively.

Results

The review identified consistent evidence that central vision loss leads to significant changes in visually guided locomotion. Individuals with CVL demonstrated reduced walking speed, increased cautious gait patterns, and greater reliance on peripheral vision during mobility tasks. Studies on obstacle negotiation have shown that individuals with CVL tend to overestimate obstacle height and adopt larger safety margins during stepping, indicating compensatory strategies to reduce the risk of falling.

Eye movement behavior was also markedly altered. Older adults with CVL exhibited closer fixation patterns, increased dependence on near-field visual information, and reduced look-ahead behavior during walking. Chapman and Hollands (2006) reported that individuals at higher fall risk demonstrated premature gaze transfer, shifting visual attention away from targets before completing stable foot contact, which was associated with increased stepping variability. Similarly, Yamada et al. (2012) showed that individuals with a history of falls or higher fall risk exhibited earlier gaze shifts in dual-task conditions, reflecting less stable visuomotor planning strategies.

In addition, studies investigating simulated central vision loss confirmed similar compensatory behaviors in healthy participants, including increased toe clearance, altered gait kinematics, and reduced visual field utilization efficiency. Interventional studies suggested that training programs and sensory substitution devices may partially improve mobility performance, although outcomes varied depending on task complexity and cognitive load.

Conclusions

Central vision loss significantly alters locomotor behavior by shifting control strategies from proactive to more reactive mechanisms. This is reflected in reduced anticipatory gaze behavior, increased gait conservatism, and modified obstacle avoidance strategies. Both clinical and simulation-based studies consistently indicate that visual degradation leads to increased reliance on peripheral visual input and altered visuomotor coordination. However, the effectiveness of assistive technologies and training interventions remains variable. Future research should focus on standardized methodologies and longitudinal designs to better understand adaptive mechanisms and optimize rehabilitation strategies for individuals with central vision loss.