Low Vision

Low vision describes any number of situations where a person has lost a significant amount of their vision, but not enough to be considered blind. It can be caused by any of a number of factors, each of which presents as a slightly different set of visual challenges. These include:

albinism
brain injuries
cataracts
diabetic retinopathy
eye injuries
eye cancer
glaucoma
hemianopia
macular degeneration
retinitis pigmentosa
retinal detachments
various infections

Design Considerations

People with low vision may rely on the browser's zoom features, or they may use screen magnification software such as ZoomText or MAGic, which show a small portion of the screen at a time. Low vision users are also often screen reader users so keep those requirements in mind as well.

When designing for users with low vision, we need to:

Use good contrasts and a readable font size. Ensure that your software passes WCAG 1.4.3 Contrast (Minimum)
Publish all information on web pages (HTML), not PDFs or other inflexible formats
Use a combination of color, shapes, and text
Follow a linear, logical layout and ensure text flows and is visible when text is magnified to 200%
Put buttons and notifications in context.
Provide a visible focus state. Ensure that your software passes WCAG 2.4.7 Focus Visible
Provide a clear visual distinction between content (text, images) and controls (buttons, links, etc.)

We need to avoid:

Disabling pinch-to-zoom
Using low color contrasts and small font sizes
Burying information in downloads
Only using color to convey meaning
Spreading content all over a page and forcing a user to scroll horizontally when text is magnified to 200%
Separating actions from their context

Sources for list above: