Evaluation of a Scanned Laser Display as an Alternative Low Vision Computer Interface

1. Evaluation of a Scanned Laser Display as an Alternative Low Vision Computer Interface Conor Kleweno, Eric Seibel, Ph.D., Kyle Kloeckner, Bob Burstein, Erik Viirre, M.D., Ph.D., Thomas Furness III., Ph.D.

2. Problem Statement: • Can the Virtual Retinal Display (VRD) be a helpful alternative low vision computer interface • A testing protocol is needed to compare the two interfaces for low vision use 1

3. Introduction: • Persons with low vision find computer use difficult with the standard computer display (CRT) • A CRT is limited in brightness and contrast • Low vision aid software can make computer use cumbersome • The VRD may be a better alternative for low vision computer users • The VRD uses a modulated, low power laser that displays an image directly onto retina using a two mirror scanning mechanism 2

4. Objectives: • Design a testing protocol to compare the VRD with a standard computer screen display (CRT) • Conduct vision tests with low vision subjects with different low vision conditions • Determine if the VRD can be an effective alternative low vision computer interface • Use an acuity test to compare visual acuity between the VRD and a CRT 3

5. Objectives (continued): • Use a reading speed test to compare reading performance between the VRD and a CRT • Determine what types of low vision benefit from VRD technology • Have low vision subjects compare the quality of images displayed between VRD and a CRT in terms of clarity and brightness

6. Testing Site Setup: • Testing conducted in a controlled environment at the Department of Services for the Blind • 15 low vision subjects with variety of conditions 4

7. Four Test Conditions: • A standard CRT with white on black contrast • A standard CRT with red on black contrast • The VRD with red on black contrast with a luminance setting of one half of the measured value of the white on black CRT • The VRD with red on black contrast with a luminance setting that matches the measured value of the white on black CRT 5

8. Procedure: • CRT acuity test used the white on black contrast • VRD acuity test used the matched luminance setting • Reading speed tests conducted at four character angle sizes • Three 20 second trials done at each character angle size • Subjects given oral questionnaire to obtain subjective data on clarity and brightness of images 6

9. Acuity Test: • Acuity tests conducted using the Landolt ring test • Pointer arrows were used to assist subject in locating image • Acuity test range was 20/1128 to 20/67 7

10. Reading Speed Tests: • Three words shown simultaneously to subject on PowerPoint slides as shown below • Subject manually advanced through slides and orally read the words • Unrelated words used • Reading speed evaluated as correctly read words per 20 second test • Box placed around words to help subject locate image bird her state 8

11. Results: Reading Speed 9

12. Results: Visual acuitySubjective responses 10

13. Discussion: • VRD increased visual acuity and reading speed in some low vision subjects • Overall, subjects with low vision conditions due to optical causes benefited most from VRD • 64% of subjects had equal or better visual acuity with the VRD • 71% of subjects found VRD images clearer • 79% of subjects found VRD images brighter • In general, subjects disliked red on black contrast • The testing protocol allowed a valid comparison between the two displays • More testing is planned to further define types of low vision that will benefit from VRD 11

14. Acknowledgements: • Human Interface Technology (HIT) Lab • Howard Hughes Medical Scholar Summer Program • John Olson and the Washington State Department of Services for the Blind, Seattle, Washington • National Science Foundation (Grant number DMI-9801294) 12