The document discusses the definitions and categories of visual impairments, listing various conditions such as low vision and blindness along with statistics on their prevalence. It emphasizes the importance of accessible design in visualization, detailing design strategies for individuals with color blindness and low vision, including contrast, layout, and the use of tactile and auditory elements. Recommendations for creating inclusive graphics and visualizations are provided, aimed at enhancing understanding for people with different visual abilities.

1. Visual impairments
8.11.2012
Nina Kaijasilta
Petri Myllys
Maiju Tompuri

2. Visual Impairments
• Visual impairments – a matter of
definition
– Visually impaired, vision impairment, partially
sighted, low vision, legally blind, totally blind,
functional loss of vision, eye disorder, retinal
degeneration, albinism, cataracts, glaucoma,
muscular problems, corneal disorders,
diabetic retinopathy, congenital disorders,
infection, cortical visual impairment

3. Visual Impairments
• Visually impaired – categorization between1:
– Low vision / partially sighted2
– Blind
• Based on WHO definition
– Visual acuity & visual field defect
1
http://www.nkl.fi/fi/etusivu/tietoa/maarittely
2
http://www.nkl.fi/fi/etusivu/tietoa/sanastoengl

4. Visual Impairments
• 285.389M visually impaired people (2010 estimate)1
– Enough reason to visualization for visually impaired
1
http://www.who.int/blindness/en/

5. Why to consider?
“A well-designed visualization facilitates the
understanding of the key messages, speeds
the process and reduces strain.
Great visualizations take into consideration,
how people receive and utilize information.”
Näsänen, 2007
Accessible design

6. Why to consider?
“The power of the web is in its universality. Access
by everyone regardless of disability is an essential
aspect.”
Tim Berners-Lee, creator of WWW

7. BLINDNESS

8. Blindness
• The WHO definition from 19721
– Case for revision:
• Interesting issue – definition of blindness:
• No distinction when it comes to perception of light
1
http://www.who.int/blindness/Change%20the%20Definition%20of%20Blindness.pdf

9. Blindness
• Another angle:
– International Council of Ophthalmology
recommends1
• Blindness: only total vision loss
• Low vision: lesser degrees of vision loss
• Visual impairment: loss of visual functions at the
organ level
1
Colenbrander 2002, 17

10. Blindness
• Complete blindness is rare1,2
• So what exactly is visualization and to
whom can we visualize?
1
http://www.nkl.fi/fi/etusivu/tietoa/maarittely
2
Nelson 2003, 29

11. LOW VISION

12. What’s low vision?
Low vision in the World Health Organization
classifications1:
•Moderate visual impairment
•Severe visual impairment
•visual field loss (loss of peripheral vision).
1http://www.who.int/mediacentre/factsheets/fs282/en/index.html

13. Severe visual impairment
Moderate visual impairment
Mild vision loss
Snellen chart: http://en.wikipedia.org/w/index.php?title=File:Snellen_chart.svg&page=1

14. Low vision
Why does it occur?
• Uncorrected refractive errors
(myopia, hyperopia or astigmatism), 43 %
• Cataract, 33%
• Glaucoma, 2%
World Health Organization1
1http://www.who.int/mediacentre/factsheets/fs282/en/index.html

15. COLOR BLINDNESS

16. Color blindness
• The colorblind have a narrowed color
perception
• There is no treatment or cure for color
blindness
Pic: http://understandinggraphics.com/wp-content/uploads/2009/10/color-blind-chart.png

17. Color vision
• Red cones – L cones
• Green cones – M cones
• Blue cones – S cones
Normal Vision Color Blindness (Protanopia)
Pic: http://www.cis.rit.edu/fairchild/WhyIsColor/Questions/3-

18. Normal vision Red-Blind/ ProtanopiaGreen-Blind/ Blue-Blind/Tritanopia
Deuteranopia
Monochromacy/ Red-Weak/ Green-Weak/ Blue-Weak/
Achromatopsia Protanomaly Deuteranomaly Tritanomaly
Simulator: http://www.colblindor.com/coblis-color-blindness-simulator/

19. Color blindness
Prevalence (Caucasian)
Type Men Women
Cone absent 2.4% 0.03%
L-cone absent (Protanopia) 1-1.3% 0.02%
M-cone absent (Deuteranopia) 1-1.3% 0.01%
S-cone absent (Tritanopia) 0.001% 0.03%
Cone defect 6.3% 0.37%
L-cone defect (Protanomaly) 1-1.3% 0.02%
M-cone defect (Deuteranomaly) 4.5-5.0% 0.35%
S-cone defect (Tritanomaly) 0.01-0.02% 0.01%
Total 8 - 10% 0.3 – 0.5%
Source: http://www.colour-blindness.com/general/prevalence/

20. Color blindness prevalence

21. Color blindness
Genetics
• Color blindness carried by the X chromosone
(recessive)

22. Color blindness
Ishihara - Color defiency test 1917
Original plates: http://colorvisiontesting.com/ishihara.htm

23. Color blindness
Hue Color Vision 1949
1
Color arrangement test 1947
2
1 Screenshot: http://www.colblindor.com/farnsworth-munsell-100-hue-color-vision-
2 Screenshot: http://www.colblindor.com/color-arrangement-test/
test/#prettyPhoto

24. Color blindness
RGB Anomaloscope 1907
1
2
1 Screenshots: http://www.colblindor.com/rgb-anomaloscope-color-blindness-test/
2 Pic: https://www.good-lite.com/Details.cfm?ProdID=570

25. HOW TO DESIGN?

26. Visualizing for blind?
• What exactly is seeing?
– Seeing could be thought as a mental
interpretation of some input

27. Visualization methods for
persons blind or partially sighted

28. How to design for the blind
• Louis Braille (1809 – 1852): braille system
1
1
http://en.wikipedia.org/wiki/File:Braille_alfabet.jpg

29. How to design for the blind
• Contrast
– “-- visual acuity depends on the contrast” 1
– ”-- contrast sensitivity thus depends on the
size of the object” 1
1
Näsänen 2007, 12

30. Modified from Joel
Schneider’s 3-page
Snellen Chart

34. How to design for the blind
• Tactile textures
– Boundaries are easy to find1
• Tactile maps
– Abstract concepts can be demonstrated2
1
Anderson 1992, 290
2
Skytt 2012, 10–12.

35. Pic: http://wiki.openstreetmap.org/w/images/4/44/Tactile_Map_Aachen.jpg

36. How to design for the blind
• Tactile combined with
sound
– IVEO Viewer1
1
1
Gardner, Bulatov & Kenny 2009

37. “Fig. 1. IVEO SVG image as seen on screen or
on the color printed image. (b) Dots embossed
with a ViewPlus embosser. Black dots have the
maximum height of 0.5 mm and gray dots are
smaller. 7 dot heights are possible” (Gardner, Bulatov
& Kenny 2009)

38. How to design for the blind
• What about Scalable Vector Graphics in
mainstream context?

39. How to design for the blind
• “To be scalable means to increase or
decrease uniformly. In terms of graphics,
scalable means not being limited to a
single, fixed, pixel size.”
(http://www.w3.org/TR/SVG11/concepts.html)

40. Bushell 2012

41. • Screen readers & special displays
– Design & development might target only a
specific (seeing) group
• Microsoft Windows first not accessible by screen
readers1
1
Vehmas 2005, 130

42. How to design for low vision
Distinguishable letters
When a picture is formed into the retina,
small details have lower contrast than larger
items. 1
Use bigger letters and graphical elements.
Letterforms need to be easily
distinguishable 1,2
1Näsänen 2007
2Dolan, RGD Ontario 2010

43. Screenshot: http://www.couchsurfing.org/

44. Screenshot: http://ripetungi.com/wp-content/uploads/2010/02/twitter-users.png

45. How to design for low vision
Enough difference in color
value
Brains compensate for a certain range of blur
that eye optics create. This applies only to
the difference in brightness, not in color. 1
A good rule of thumb is to ensure at least a
70% difference in color value between e.g.
type and a background tone. 2
1Näsänen 2007
2Dolan, RGD Ontario 2010

46. http://blog.mainstreethost.com/

47. How to design for low vision
Focus on layout
We see sharply only in the center of the
visual field because the amount of ganglian
cells reduces when not in the focus point. 1
information needs to be clearly placed, and
the layout can be understood with one
glance.1
1Näsänen 2007

48. Screenshot: http://laitilan.com/

49. Screenshot: http://www.mtv3.fi/

50. Screenshot: http://www.fox.com/

51. How to design for low vision
Is extra bling bling needed?
Every day we do approximately 100 000 eye
fixations. Each fixation takes at least 0,15
seconds.1
Avoid animations and flashy content if they
don’t bring extra value to the visualization.
However, use of graphic visualizations is
recommended.1
1Näsänen 2007

52. Screenshot: http://producten.hema.nl/

53. How to design for low vision
Make it accessible
There is a wide variance in users’ ability to
operate a mouse, keyboard or other input
device. Some people may use voice-
recognition programs with spoken
commands. 1
Make all functionality fully accessible from a
keyboard and create content that can be
presented in different ways.1
1Dolan, RGD Ontario 2010

54. Pic: http://notabilia.net/

55. How to design for color blinds
• Colors should never be the only method of
conveying important information!
This is important

56. How to design for colorblinds
• Avoid placing red and green together
– Also minor color &contrast differences 2
• Desaturate images to see if they still have
impact
1
1http://blog.templatemonster.com/2012/03/21/designing-colorblind-friendly-website/
2 http://www.tfl.gov.uk/assets/downloads/standard-tube-map.pdf

57. How to design for colorblinds
Bad examples: BBC Online
Sceenshot: http://wearecolorblind.com/example/bbc-online-football-tables/

58. How to design for colorblinds
• In graphs
– Place the legend directly in
the chart
– Display the type of data for
each element in a tooltip
Blue Green Purple Red
• Name the color in text as
well

59. How to design for colorblinds
Bad example: Google Analytics
Sceenshot: http://wearecolorblind.com/example/google-analytics/

60. How to design for colorblinds
• Increase contrast, change hue, add shapes
Bernhard J. & Vaughn Kelso N. 2007

61. How to design for colorblinds
• Use varied icons and shapes
Bernhard J. & Vaughn Kelso N. 2007

62. How to design for colorblinds
Problematic colors
High Medium Low
Light Green and
Green and Red Blue and Yellow
Yellow
Green and Brown Blue and Grey Yellow and Violet
Blue and Purple Green and Grey Dark blue and Black
Green and Blue Green and Black
Pic: http://jfly.iam.u-tokyo.ac.jp/color/

63. How to design for colorblinds
Unambiguous Colors
• For both to colorblinds and non-colorblinds
Simulation
Original Protan Deuter Tritan
Black
Orange
Sky Blue
Bluish Green
Yellow
Blue
Vermillon
Reddish Purple
Colors: http://jfly.iam.u-tokyo.ac.jp/color/image/pallete.jpg

64. Curious about color blindness?
• Watch video: ”No such thing as color – what it
is like to be colorblind”
– http://www.nosuchthingascolor.com/
• We are colorblind - Blog by Tom van
Beveren, colorblind (deuteranomally)
• http://wearecolorblind.com/

65. Test your designs
• Color blindness simulation
– http://vischeck.com/
– http://www.colblindor.com/coblis-color-
blindness-simulator/
• Contrast test
– http://www.checkmycolours.com/
– http://www.snook.ca/technical/colour_contrast
/colour.html
• Grayscale images and visualizations

66. Conclusions
• Many people with visual impairments
– Create accessible design
• Use guidelines in design
– Contrast
– Size
– Color
– Layout
– Format

67. References
• Anderson, Frances 1992. Art for all the children: approaches to art therapy for children with
disabilities. Springfield, Charles C Thomas.
• Bernhard, J.& Vaughn Kelso, N. 2007. Color Design for the Color Vision Impaired.
Cartographic Perspectives, 58, p. 61-67.
• Bushell, David 2012. Resolution Independence With SVG. Read 30.10.2012.
http://coding.smashingmagazine.com/2012/01/16/resolution-independence-with-svg/
• Colenbrander, August 2002. Visual Standards: Aspects and Ranges of Vision Loss with Emphasis
on Population Surveys. International Council of Ophthalmology. Read 23.10.2012.
http://www.icoph.org/downloads/visualstandardsreport.pdf
• Color Blindness. Prevalence. Accessed 01.11.2012.
http://www.colour-blindness.com/general/prevalence/
• Dolan, D., A Practical Handbook on Accessible Graphic Design 2010, RGD Ontario
• Flück, D. 2012. Colblindor - Color Blindness viewed through Colorblind Eyes. Accessed 30.10.2012.
http://www.colblindor.com/
• Gabriel-Petit, P. 2007. Ensuring Accessibility for People With Color-Deficient Vision. Accessed
01.11.2012 http://www.uxmatters.com/mt/archives/2007/02/ensuring-accessibility-for-people-with-
color-deficient-vision.php
• Gardner, John; Bulatov, Vladimir & Kelly, Robert 2009. Making Journals Accessible to the Visually-
Impaired – The Future is Near. Learned Publishing 22(4) 2009 pp. 314-319. Read 30.10.2012.
http://www.viewplus.com/about/abstracts/09learnpubgardner.html
• ICD Update and Revision Platform: Change the Definition of Blindness. World Health Organization.
Read 23.10.2012.
http://www.who.int/blindness/Change%20the%20Definition%20of%20Blindness.pdf
• Malamed, C. 2012. Designing for Color Blindness.
http://understandinggraphics.com/design/designing-for-color-blindness/
• Mariotti, S. P., Global Data on Visual Impairments 2010, World Health Organization

68. References
• Nelson, Scott 2003. A Professional Artist and Curator Who Is Blind. Art Beyond Sight – A Resource
Guide to Art, Creativity and Visual Impairments, 28–29. Ed. Axel, Elisabeth & Levent, Nina. New York,
AEB & AFB.
• New estimates of visual impairment and blindness: 2010. World Health Organization. Read
23.10.2012.
http://www.who.int/blindness/en/
• Näkövammaisuuden määrittely. Näkövammaisten Keskusliitto ry. Read 23.10.2012.
http://www.nkl.fi/fi/etusivu/tietoa/maarittely
• Sanastoa englanniksi. Näkövammaisten Keskusliitto ry. Read 23.10.2012.
http://www.nkl.fi/fi/etusivu/tietoa/sanastoengl
• Näsänen, Risto 2007. Visuaalisen käytettävyyden opas 2007. Read 18.10.2012.
http://www.ttl.fi/fi/ergonomia/kognitiivinen_ergonomia/visuaalinen_kaytettavyys/Documents/Visuaalise
n_kaytettavyyden_opas_2007.pdf
• Okabe, M. & Ito, K. 2002. Color Universal Design (CUD) - How to make figures and presentations that
are friendly to Colorblind people – Accessed 29.10.2012.
http://jfly.iam.u-tokyo.ac.jp/color/
• Saarelma, O. 2012. Värisokeus ja poikkeava värinäkö. Lääkärikirja Duodecim. Accessed 28.10.2012.
http://www.terveyskirjasto.fi/terveyskirjasto/tk.koti?p_osio=100&p_artikkeli=dlk00347&p_teos=dlk&p_s
elaus=7728
• Scalable Vector Graphics (SVG) 1.1 (Second Edition), W3C Recommendation 2011. Read
30.10.2012.
http://www.w3.org/TR/SVG11/concepts.html
• Schneider, Joel. 3-page Snellen Chart. Read 25.10.2012.
http://www.i-see.org/eyecharts.html/#download
• Skytt, Riitta 2012. Koskettavaa luettavaa. Tukilinja 3–4 2012. Read 16.10.2012.
http://www.virtualmagnet.eu/magnet/asiakkaat/Tukilinja/tukilinja_030412.html/
• Van Beveren, T. 2012. A quick introduction to colorblindness. Accessed 30.10.2012.