Developing a Very Low Vision Orientation and Mobility Test Battery (O&M-VLV).

Area of Science:

• Ophthalmology and Vision Science
• Rehabilitation Medicine
• Human Factors and Ergonomics

Background:

• Severe vision loss significantly impacts daily functioning, particularly orientation and mobility (O&M).
• Existing O&M assessments may not adequately capture the challenges faced by individuals with profound visual impairment.
• There is a need for validated O&M assessments for low vision rehabilitation and vision restoration clinical trials.

Purpose of the Study:

• To determine the feasibility of assessing vision-related orientation and mobility (O&M) tasks in individuals with severe vision loss.
• To evaluate the utility of these O&M tasks as potential outcome measures for low vision rehabilitation and vision restoration trials.

Main Methods:

• Forty participants with severe vision loss (legally blind, advanced retinitis pigmentosa) underwent the Orientation & Mobility-Very Low Vision (O&M-VLV) subtests.
• Tasks included route travel in simulated environments, room orientation, visual exploration, and a modified Timed Up and Go (TUG) test.
• Residual visual function (acuity and visual fields) and spatial cognition were measured alongside O&M task performance.

Main Results:

• Performance across O&M-VLV tasks demonstrated significant associations with residual visual function.
• Walking speed was linked to visual field extent (p < 0.01), while obstacle contact correlated with visual acuity (p = 0.001).
• The 'gallery' task score uniquely correlated with both visual acuity and visual fields (p < 0.001).

Conclusions:

• The O&M-VLV protocol is feasible for assessing O&M performance in individuals with severe vision loss.
• Task performance is significantly associated with remaining visual acuity and visual fields, validating its use.
• This assessment protocol offers valuable orientation and mobility measures for vision restoration clinical trials and rehabilitation.