Vision Simulator loads any public web page and shows it as it looks to people with different kinds of colour blindness and low vision. It is the most persuasive tool in the portal for showing someone why accessibility matters.
Loading a page
Enter an address in Load a Page and choose Load Live Page. We load a copy of the page and show it in the preview. Interaction in the preview is turned off, so links and forms do nothing. Cookie banners are hidden automatically so they do not cover the page.
The simulations
| Mode | What it shows |
|---|---|
| Normal | The page as it is. |
| Protanopia | Red blindness. |
| Deuteranopia | Green blindness, the most common form. |
| Tritanopia | Blue blindness. |
| Achromatopsia | No colour vision at all. |
| Blurred | Blurred vision. |
| Cataracts | Low contrast, cloudy vision. |
| Tunnel | Loss of peripheral vision. |
Viewing options
Switch between desktop, tablet and mobile widths, zoom from 30% to 150%, and use Fullscreen for presenting. Press Escape to leave fullscreen.
Contrast Fixes
The simulator also checks the loaded page for contrast and legibility problems: text below the required contrast, links that differ from text only by colour, faint input borders and placeholder text, very small text, and small tap targets. Turn on Show Fixed Version to see the page with suggested fixes applied. Fix Details lists each one with its before and after values and a Locate on page button.
The fixed version is a preview only. Nothing on your real site changes.
If a page will not load
Some sites block automated visitors or show a security check first. If the preview shows a security check instead of your page, it is your site's bot protection. Try another page or ask whoever manages your hosting.