A Standardized Obstacle Course for Assessment of Visual Function in Ultra Low Vision and Artificial Vision

Summary

We describe an indoor, portable, standardized course that can be used to evaluate obstacle avoidance in persons who have ultralow vision. The course is relatively inexpensive, simple to administer, and has been shown to be reliable and reproducible.

Abstract

We describe an indoor, portable, standardized course that can be used to evaluate obstacle avoidance in persons who have ultralow vision. Six sighted controls and 36 completely blind but otherwise healthy adult male (n=29) and female (n=13) subjects (age range 19-85 years), were enrolled in one of three studies involving testing of the BrainPort sensory substitution device. Subjects were asked to navigate the course prior to, and after, BrainPort training. They completed a total of 837 course runs in two different locations. Means and standard deviations were calculated across control types, courses, lights, and visits. We used a linear mixed effects model to compare different categories in the PPWS (percent preferred walking speed) and error percent data to show that the course iterations were properly designed. The course is relatively inexpensive, simple to administer, and has been shown to be a feasible way to test mobility function. Data analysis demonstrates that for the outcome of percent error as well as for percentage preferred walking speed, that each of the three courses is different, and that within each level, each of the three iterations are equal. This allows for randomization of the courses during administration.

Abbreviations:
preferred walking speed (PWS)
course speed (CS)
percentage preferred walking speed (PPWS)

Introduction

Low vision rehabilitation assessments must determine whether intervention results in improvement in function. Performance metrics typically involve computer based reading or functional assessments^1-9 as well as quality of life questionnaires^10-15. Being able to also assess the low vision patient's ability to navigate around obstacles might also provide clues to functional improvements¹⁸ particularly in the case of artificial vision devices. Geruschat et al. recently published navigation outcomes with a retinal implant chip, highlighting the need for a standard metric in this area¹⁷. Currently....

Protocol

1. Course Construction

1. Install course floor. Course dimensions are 40 ft long by 7 ft wide consisting of 280 1 ft² portable floor tiles (beige event floor tiles). Place with black trim around perimeter only (Figure 1).
2. Paint the adjacent walls to match the floor tiles creating a somewhat monochromatic environment. Colors we used with greyscale values are provided (Table 5). If the specific colors are not available, we recommend taking a tile to a hardware store for color matching.
3. Install lighting according to the lighting template (Figure 1). Connect lights to dimmer switch.....

Results

Subjects

Six sighted blindfolded, sighted, and 36 completely blind but otherwise healthy adult (age range 19-85 years), male (n=29) and female (n=13) subjects were enrolled in one of three studies involving testing of the BrainPort sensory substitution device (Wicab, Madison WI). All studies were approved by the University of Pittsburgh IRB and all subjects signed an approved informed consent document. All studies were a within subjects, repeated measures design such that each subject acted as th.......

Discussion

We describe an indoor, portable, easily reproducible, and relatively inexpensive course that can be used to evaluate obstacle avoidance in persons who are blind or have low vision. Most current obstacle course designs and tests (i.e. TUGS) are difficult to compare across sites and observers, or are permanent instillations which cannot readily be performed at alternate locations^16,17,30. Our goal was to create a course that could be standardized for use at different locations and with different observe.......

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
Event Floor Tiles, beige	Snaplock Industries, Salt Lake City UT		Beige
Event Floor Tiles, black trim	Snaplock Industries, Salt Lake City UT		Male loop
Event Floor Tiles, black trim	Snaplock Industries, Salt Lake City UT		Female loop
Event Floor Tiles, Edging	Snaplock Industries, Salt Lake City UT		Black
Wall Paint: Satin Premium Plus Internal Satin Enamel Custom Color Match	Behr, Inc Santa Ana CA	custom	Greyscale value = 45
Obstacle paint	Valspar Paints, Wheeling, IL	DuJour (#70002-6)	DuJour Greyscale value = 15
Obstacle paint	Valspar Paints, Wheeling, IL	Fired Earth (#6011-1)	Fired Earth Greyscale value = 95
Styrofoam obstacles	Universal Foam Products, Orlando CA	custom
Con-Tact Brand Contact Paper	Lowe's Home Improvement	639982	Solid Black
Con-Tact Brand Contact Paper	Lowe's Home Improvement	615542	Stainless Steel
Con-Tact Brand Contact Paper	Lowe's Home Improvement	614416	Solid White
3 ft x 6 ft Standard tuff Olefin Floor Mat	Commercial Mats and Rubber A Division of Georgia Mills Direct Saratoga Springs, NY		Charcoal
3 ft x 6 ft Standard tuff Olefin Floor Mat	Commercial Mats and Rubber A Division of Georgia Mills Direct Saratoga Springs, NY		Smoke
Fisher Scientific Traceable Dual Range Light Meter	Fisher Scientific	06-662-63	International Light, Newburyport MA, USA
5 1/2 in Clamp Light	Lowe's Home Improvement	203198
GE 65-Watt indoor incandescent flood light bulb	Lowe's Home Improvement	163209