Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2019 Nov 1;19(13):22.
doi: 10.1167/19.13.22.

Performance of complex visual tasks using simulated prosthetic vision via augmented-reality glasses

Elton Ho  1   2 , Jack Boffa  2 , Daniel Palanker  2   3
Affiliations

Performance of complex visual tasks using simulated prosthetic vision via augmented-reality glasses

Elton Ho et al. J Vis. .

Abstract

Photovoltaic subretinal prosthesis is designed for restoration of central vision in patients with age-related macular degeneration (AMD). We investigated the utility of prosthetic central vision for complex visual tasks using augmented-reality (AR) glasses simulating reduced acuity, contrast, and visual field. AR glasses with blocked central 20° of visual field included an integrated video camera and software which adjusts the image quality according to three user-defined parameters: resolution, corresponding to the equivalent pixel size of an implant; field of view, corresponding to the implant size; and number of grayscale levels. The real-time processed video was streamed on a screen in front of the right eye. Nineteen healthy participants were recruited to complete visual tasks including vision charts, sentence reading, and face recognition. With vision charts, letter acuity exceeded the pixel-sampling limit by 0.2 logMAR. Reading speed decreased with increasing pixel size and with reduced field of view (7°-12°). In the face recognition task (four-way forced choice, 5° angular size) participants identified faces at >75% accuracy, even with 100 μm pixels and only two grayscale levels. With 60 μm pixels and eight grayscale levels, the accuracy exceeded 97%. Subjects with simulated prosthetic vision performed slightly better than the sampling limit on the letter acuity tasks, and were highly accurate at recognizing faces, even with 100 μm/pixel resolution. These results indicate feasibility of reading and face recognition using prosthetic central vision even with 100 μm pixels, and performance improves further with smaller pixels.

PubMed Disclaimer

Figures

Figure 1
Figure 1
Experimental setup. (a) Schematic of the experimental setup. High resolution images are presented on a monitor. The front camera of the augmented-reality (AR) glasses captures the video stream. Custom software preloaded on the AR glasses adjusts the video quality to mimic prosthetic vision and displays it in the AR glasses. (b) A subject in front of the apparatus. (c) Illustration of vision through the AR glasses.
Figure 2
Figure 2
Face recognition task. (a) An example set of five faces presented. Subjects were asked to pick the face that matches the identity of the central person. Each face spanned approximately 5° × 5°. (b) Effects of the number of grayscale levels and resolution on an image.
Figure 3
Figure 3
Letter acuity results (n = 13 for 30 and 60 μm pixels; n = 19 for natural vision and 100 μm pixels). The leftmost data point at 5 μm indicates visual acuity (VA) for natural vision of the subjects. Error bars are presented in terms of SD.
Figure 4
Figure 4
Sentence reading speed in words per minute (WPM). (a) Simple sentences. (b) Complex sentences. Faded lines represent individual measurements, and the bold lines represent the population mean.
Figure 5
Figure 5
Face recognition. (a) Accuracy. (b) Response time. (c) Response time normalized to 100 μm pixels and eight grayscale levels. Each dot represents an independent measurement. Error bars are presented in terms of SD.
See this image and copyright information in PMC

Similar articles

See all similar articles

Cited by

See all "Cited by" articles

References

    1. Barrett J. M, Berlinguer-Palmini R, Degenaar P. Optogenetic approaches to retinal prosthesis. Visual Neuroscience. (2014);31(4–5):345–354. - PMC - PubMed
    1. Brainard D. H. The psychophysics toolbox. Spatial Vision. (1997);10:433–436. - PubMed
    1. Chang M, Kim H, Shin J, Park K. Facial identification in very low-resolution images simulating prosthetic vision. Journal of Engineering. (2012);9(4):046012. - PubMed
    1. Chen S. C, Hallum L, Lovell N, Suaning G. J. Visual acuity measurement of prosthetic vision: A virtual-reality simulation study. Journal of Neural Engineering. (2005);2(1):S135. - PubMed
    1. Chen S. C, Suaning G. J, Morley J. W, Lovell N. H. Chen Simulating prosthetic vision: I. Visual models of phosphenes. Vision Research. (2009);49(12):1493–1506. - PubMed

Publication types

-