How does the extent of central visual field loss affect adaptive gait?

Area of Science:

• Ophthalmology
• Biomechanics
• Gerontology

Background:

• Visual impairment is a major risk factor for falls.
• The impact of increasing central visual field loss (CFL) on adaptive gait remains unclear.

Purpose of the Study:

• To investigate how adaptive gait is affected by varying degrees of central visual field loss (CFL).
• To determine if there is a threshold of CFL that compromises gait adaptation.

Main Methods:

• 10 healthy young adults (22 ± 3 years) navigated an obstacle under three conditions: full vision, simulated 10° CFL, and simulated 20° CFL.
• Movement kinematics were analyzed during the approach and crossing of the obstacle.

Main Results:

• Participants in the 20° CFL condition exhibited more cautious and variable gait compared to 10° CFL and full vision.
• Adaptations included increased foot clearance, slower foot movement over the obstacle, and longer obstacle negotiation time in the 20° CFL condition.
• These gait modifications were specifically linked to the 20° CFL condition, suggesting a critical level of visual field loss.

Conclusions:

• Adaptive gait is significantly altered by substantial central visual field loss (≥20°).
• Gait compromise appears to occur only after central visual field loss exceeds a specific threshold.
• Findings highlight the importance of central vision for safe obstacle negotiation and fall prevention.