Traffic gap judgment in people with significant peripheral field loss

Area of Science:

• Ophthalmology
• Visual Neuroscience
• Human Factors Engineering

Background:

• Peripheral field loss (PFL) significantly impacts daily activities, including street crossing.
• Self-reported difficulties in street crossing are common among individuals with PFL.

Purpose of the Study:

• To compare traffic gap judgment accuracy between individuals with PFL and normally sighted individuals.
• To investigate the influence of PFL on the ability to identify safe street crossing opportunities.
• To explore the roles of visual and nonvisual factors in traffic gap judgment.

Main Methods:

• Eight subjects with PFL (binocular visual field <20 degrees) and five normally sighted (NV) controls participated.
• Participants judged safe crossing times at a street, with eye movements and fixation patterns recorded.
• Street-crossing behavior, habitual strategies, and perceived difficulties were assessed.

Main Results:

• PFL subjects identified 12% fewer crossable gaps and made 23% more errors (p < 0.05).
• Reduced performance correlated with smaller fixation areas and fewer relevant task fixations (p = 0.006, p = 0.001).
• Habitual crossing approach and perceived difficulties significantly correlated with judgment performance (r > 0.60).

Conclusions:

• Significant peripheral field loss leads to reduced acquisition of visual traffic information.
• This results in impaired judgment of safe street crossing gaps, posing safety risks.
• Addressing PFL-related deficits in visual perception is crucial for improving street crossing safety.