Lourdes Moreno, Xabier Valencia, J. Eduardo Pérez, and Myriam Arrue. 2018. Exploring the Web navigation strategies of people with low vision. In Proceedings of the XIX International Conference on Human Computer Interaction (Interacción 2018). ACM, New York, NY, USA, Article 13, 8 pages

1. Exploring the Web navigation strategies of
people with low vision
Lourdes Moreno
(lmoreno@inf.uc3m.es)
Computer Science Department
Universidad Carlos III de Madrid
Xabier Valencia, J. Eduardo Pérez, Myriam Arrue
EGOKITUZ: Laboratory of HCI for Special Needs
University of the Basque Country (UPV/EHU)
September 12–14, 2018, Palma, Spain

2. •Lourdes Moreno, Xabier Valencia, J. Eduardo Pérez, and Myriam
Arrue. 2018. Exploring the Web navigation strategies of people
with low vision. In Proceedings of the XIX International
Conference on Human Computer Interaction (Interacción 2018).
ACM, New York, NY, USA, Article 13, 8 pages. DOI:
https://doi.org/10.1145/3233824.3233845
•https://dl.acm.org/citation.cfm?id=3233845
•
Interacción 2018, September 12–14, 2018, Palma, Spain

3. INTRODUCTION
Scope
• “Low vision” refers to visual impairments other
than blindness
• Impairments that cannot be corrected with
regular glasses, contact lenses, medicine, or
surgery
• Visual Impairments
• Visual Acuity
• Light Sensitivity
• Contrast Sensitivity
• Field of Vision
• Colour Vision
• Functional Vision
Interacción 2018, September 12–14, 2018, Palma, Spain

4. INTRODUCTION
Incidence
•There are 246 million people
worldwide who have low vision
•Increase: aging population
Interacción 2018, September 12–14, 2018, Palma, Spain

5. INTRODUCTION
Accessibility Barriers
•People with low vision experience accessibility
barriers when they interact with the web
• Small font sizes
• Font colours that make reading even more
difficult
• Background images on web pages that
decrease legibility
Interacción 2018, September 12–14, 2018, Palma, Spain

6. INTRODUCTION
Assistive Technologies (AT)
•In order to access the web, people with
low vision employ assistive technologies
• Screen magnifiers: magnification,
colour inversion, cursor enhancement
features
• Digital magnifying glass
• Screen readers: transform web
content into auditory output
•Web browser zooming tools
Interacción 2018, September 12–14, 2018, Palma, Spain

7. INTRODUCTION
Motivation
• Incidence
• Regulatory framework
• Accessibility barriers
• The majority of the research has been
oriented towards total blindness rather than
low vision
=> Opportunities exist for improving low vision
accessibility
Interacción 2018, September 12–14, 2018, Palma, Spain

8. OBJECTIVE
•To explore the navigation strategies of low vision users in order to
select the appropriate accessibility techniques to employ in the
designing of web interfaces for this group
• Literature review
• Exploratory study
Interacción 2018, September 12–14, 2018, Palma, Spain

9. LITERATURE REVIEW
•More focused on blind users or people with visual disabilities,
without distinguishing between the specific needs of blind and
low vision users
Interacción 2018, September 12–14, 2018, Palma, Spain
•Low Vision works:
• Accessibility guidelines: basic transformations
• Font size, font family, font colour, letter spacing,
hyperlink colours
• A personalized user interface approach: one
single method of adapting the presentation
may not be sufficient due to the heterogeneity
of the group.

10. LITERATURE REVIEW
•Accessibility standard: Web Content Accessibility Guidelines (WCAG)
• Referenced in the regulatory compliance frameworks (Section 508,
EN 301 549, WCAG)
Interacción 2018, September 12–14, 2018, Palma, Spain
•WCAG 2.0 has deficiencies and fails to meet
web accessibility requirements for people with
low vision
• Low Vision Accessibility Task Force (LVTF) =>
Accessibility Requirements for People with
Low Vision
• (new recommendation) WCAG 2.1

11. LITERATURE REVIEW
• Navigation strategies differ for visually
impaired users according to the AT used
• Interaction with the magnification software:
• Partial view of the page (loss of context)
• Horizontal scrolling
Þ Users are required to move their field of
vision frequently (numerous gestures)
• Some works question the support capacity of
assistive technology
Interacción 2018, September 12–14, 2018, Palma, Spain

12. LITERATURE REVIEW
•Alternative assistive technologies other than the traditional ones
used to improve accessibility for people with low vision
• Multi-modal user interfaces
• Conceptual approaches for making web pages accessible
• A browser that allows parameters to be adjusted in order to
maximize reading efficiency
Interacción 2018, September 12–14, 2018, Palma, Spain

13. EXPLORATORY STUDY
Participants
•Six participants from the
Spanish Association of
People with Low Vision
•Experimental sessions
(UC3M, Servimedia)
•Observational methods
•Participants’ interactions
were recorded with a
camera located behind them
during experimental
sessions.
Interacción 2018, September 12–14, 2018, Palma, Spain
ID
Gender
Age
Assistive
Technology
Web
Expertise
U1 M 44 ZoomText 9.1 High
U2 F 54 Browser Zoom High
U3 F 52
ZoomText 10 +
Text Reader +
Browser Zoom
High
U4 F 65 Browser Zoom Medium
U5 M 45
ZoomText 10 +
Browser Zoom
High
U6 F 41 Browser Zoom High

14. EXPLORATORY STUDY
Stimuli
•Discapnet website
• WCAG
• The Barrier Walkthrough Method
revealed some accessibility barriers
for people with low vision
• Insufficient visual contrast
• Lines of text that are too long
• Inflexible page layout
• Failure to implement skip links
• ……
Interacción 2018, September 12–14, 2018, Palma, Spain

15. EXPLORATORY STUDY
Procedure
•Inform participants of the purpose of the
experiment
•Sign a consent form
•Search tasks on the website without using a
search engine or any other similar facilitator
•The target page was three links away from the
homepage
•Time for performing the task was limited to ten
minutes.
Interacción 2018, September 12–14, 2018, Palma, Spain

16. EXPLORATORY STUDY
Information analyzed
•Task completion time
•Total number of pages visited
•Number of pages revisited during the task
•Lostness formula
•Number of zoom magnify operations
•Number of zoom de-magnify operations
•Number of vertical page scrolling actions
•Number of horizontal page scrolling actions
Interacción 2018, September 12–14, 2018, Palma, Spain

17. EXPLORATORY STUDY
Results
• The navigation bar component is the most explored element, used by
participants as a reference point.
• Scrolling actions
• Vertical scrolling does not present any difficulties (mouse wheel)
• Horizontal scrolling requires a more complex sequence of actions and
causes loss of context
• Moving the field of vision to the bottom of the page
• Clicking
• Dragging the scroll bar
• Going back to the content
• Horizontal scrolling occurred depending on the magnification applied to
the webpage
Interacción 2018, September 12–14, 2018, Palma, Spain

18. EXPLORATORY STUDY
Results
• Some participants accessed the web page that contained the target
link but did not locate it.
• The link was visible on the screen
• However, participants were focused on the main content of the
webpage at the centre of the screen while the link was out of their
sight on the left side of the screen
• Multiple columns are problematic
• Certain factors such as small font sizes, contrast with font and
background colours decreased legibility
Interacción 2018, September 12–14, 2018, Palma, Spain

19. EXPLORATORY STUDY
Results
•Magnification levels
Interacción 2018, September 12–14, 2018, Palma, Spain

20. EXPLORATORY STUDY
Results
• Magnification actions were performed before the following actions:
• Exploring vertical/horizontal navigation bars
• Clicking on a link located on the vertical navigation bar
• Using the vertical scroll bar
• Demagnification actions were performed before the following actions:
• Exploring the content
• Clicking on the browser’s back button
• Exploring the horizontal navigation bar
• Clicking on a link located on the horizontal navigation bar
• Using the horizontal scrollbar
(“ctrl” key together with the mouse wheel)
Interacción 2018, September 12–14, 2018, Palma, Spain

21. EXPLORATORY STUDY
Discussion
• Including the navigation bar component near the top of the page
• Minimizing the magnification / demagnification operations:
• Presenting important information with a large font size
• Organizing text in small blocks
• Presenting important information close to the centre of the screen
• Adding a visible hot area around links
• Using presentation properties that distinguish the links
• With regard to avoiding the horizontal scroll:
• Linearize the page
• Responsive design
Interacción 2018, September 12–14, 2018, Palma, Spain

22. CONCLUSIONS
• People with low vision experience accessibility barriers when they
interact with the web, despite using their assistive technology
• In order to discover the navigation strategies used by people with low
vision to avoid accessibility barriers we carried out:
• A review of the corresponding literature
• An exploratory study with six users with low vision
• Solution: web user interface approaches based on adaptation
techniques to provide a better web navigation experience
corresponding to specific individual user needs, such as the type of
assistive technology used
Interacción 2018, September 12–14, 2018, Palma, Spain

23. WORK IN PROGRESS
•Proposal of the adaptation techniques
combining techniques obtained in this
study with others proposed in the
literature
•Automated transcoding system
• An adapted web interface for people with
low vision is generated from a web
interface.
•An experimental study with users with
low vision to validate the approach
Interacción 2018, September 12–14, 2018, Palma, Spain

24. Exploring the Web navigation strategies of
people with low vision
Lourdes Moreno
Information Technology Department
Carlos III University of Madrid
Xabier Valencia, J. Eduardo Pérez, Myriam Arrue
EGOKITUZ: Laboratory of HCI for Special Needs
University of the Basque Country (UPV/EHU)
September 12–14, 2018, Palma, Spain