Impaired vision assistive technology
On this guide page
Magnifiers
A variety of devices and applications allow people to magnify parts or all of a screen or document. They may need to shrink or enlarge what they see.
Example: This is the default size of the browser and webpage.
Some apps and devices have a setting for increasing the size of the buttons or user interface.
Some apps and devices have a setting for increasing the size of everything.
This helps people with low vision. Yet, problems can occur when they magnify the screen:
- Are they missing something on the other side of the screen?
- Does the text not wrap around for easy reading?
- Did the author force text size on the audience? Does that make the text illegible?
Magnifiers cannot fix reading issues when viewing images of text. They will be difficult or impossible to read. The text should not be an image of text.
Color Filters and High Contrast
Color filters, like grayscale or custom color schemes, help people with light sensitivity. High-contrast options help people with headaches and other visual issues.
The grayscale color filter is good for checking if people with color blindness will be able to read the digital content. Notice how without colors, you would need a different indicator in addition to color for any links, warnings, or other important information.
This custom color scheme uses only yellow and black. If someone used red to indicate importance, that cannot be seen in this theme. An additional identifier would be required.
This custom color scheme is high contrast. It ignores all the color decisions of the author of this digital content, so it can be read by the person who needs it. That means colors may be different than your original instructions.
This helps people with low vision, color blindness, headaches, and more. Yet, problems can occur when they use color filters and schemes:
- Did the author force colors on the audience? Did that make the text illegible?
- Did the author use color to indicate meaning or purpose?
The colors the author chooses are not always the colors the audience sees. The author should allow the audience to change the colors with ease. This is done by sticking to the color theme. The author should adjust the color theme directly if the author does not like them. That allows the audience to change the color theme as needed.
The author should also ensure anything using color to symbolize something has an additional identifier. This can include text (e.g., "required"), characters, or symbols.
Links are typically distinguishable by using the underline format. Therefore, no other text should be underlined. This avoids confusion over the meaning of the underline.
Reduce Blue Light
Screens emit blue light that causes eye strain and headaches. Ways to reduce blue light:
- Glasses (e.g., prescription glasses, computer glasses) with a blue filter
- "Dark" appearance mode setting on various devices or apps
- "Night" display modes on various devices or monitors