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Dyslexia and colour blindness — font and colour strategies when you have both

11 min read · September 5, 2026

Most dyslexia reading guides recommend tinted overlays, cream or pale-blue backgrounds, and coloured underlining to mark grammar errors. That advice can backfire badly if you also have colour blindness. Somewhere between 5% and 10% of people who have dyslexia also have some form of colour vision deficiency — and the two conditions pull in opposite directions on several key settings. This article is for that overlap.

The two conditions, briefly

Dyslexia is primarily a phonological processing difficulty — the brain's mapping between written letters and sounds is less automatic than in typical readers. On the visual side, many (not all) dyslexic readers also experience what researchers call visual stress: text appears to shimmer, crowd together, or drift on the page, particularly against a stark white background. This is why warm tinted backgrounds (cream, pale yellow, light grey) are a standard accommodation — they reduce the contrast enough to ease visual stress without making text hard to read.

Colour blindness (colour vision deficiency, or CVD) is a separate condition affecting the cone cells in the retina. The most common form, red-green colour blindness, affects roughly 8% of men and around 0.5% of women of Northern European descent. People with CVD cannot distinguish certain pairs of colours reliably — most commonly reds and greens, but also, in some variants, blues and yellows. Importantly, CVD affects hue discrimination, not brightness. A person with red-green CVD still perceives luminance contrast (light vs dark) normally.

The trouble starts when dyslexia accommodations rely on hue cues that CVD removes.

Where the advice conflicts

Here are the most common dyslexia accommodations and how each holds up under colour blindness:

Accommodation	Helps with dyslexia?	Problem with CVD
Cream / pale-yellow background	Yes — reduces visual stress	Usually fine. Cream is a luminance shift, not a hue shift. Works for all CVD types.
Coloured overlays (pink, blue, green tints)	Sometimes — Irlen syndrome approach	Green and red overlays may look identical to protanopes/deuteranopes. Test on your actual CVD type.
Spell-check red underlines	Neutral (doesn't help dyslexia directly)	Red-green CVD makes red underlines on white text nearly invisible. A serious usability failure.
Coloured headings to mark structure	Helps navigation	Hue alone is unreliable. Weight (bold) and size differences are needed too.
Dark mode (dark background, light text)	Mixed — depends on the person	Generally safe. Luminance contrast is preserved in CVD. But some dark-mode colour schemes (red-on-dark) fail.
Dyslexia-friendly fonts	Yes — reduces letter confusion	No conflict. Font shape is independent of colour vision.

Background colour: what actually works for both

The standard dyslexia guidance is to move away from pure white (#FFFFFF) toward a warm, slightly muted background. That guidance holds even for people with CVD, because it is based on luminance reduction, not hue preference. A cream background (#FAF5E4 or similar) has lower luminance than white, which reduces the halation effect many dyslexic readers describe — the sense of letters bleeding into the background.

What you want to avoid are background-colour recommendations that depend on hue alone — "try a pale green" or "use a sky-blue overlay" — without specifying the lightness value. A pale green at 95% lightness works fine for most readers. A mid-saturation green at 60% lightness may look identical to a mid-saturation red for a deuteranope, and both may feel subjectively wrong.

Background colours that work regardless of CVD type

Cream

Warm grey

Pale lilac

Pale blue

Dark navy

These all achieve their effect through luminance value rather than hue. Lilac and pale blue are visible to all common CVD types because they sit far from the red-green confusion axis.

Pale lilac (a very light purple) is worth highlighting. It does not sit on the red-green confusion axis, so it is reliably distinguishable for protanopes, deuteranopes, and tritanopes. Several readers in dyslexia forums report it reduces visual stress as effectively as cream. It is a useful alternative when warm tones feel too yellowed on your particular display.

For a full breakdown of background colour options and the research behind them, see our article on background colours for dyslexia.

The red underline problem

This is the most practically painful conflict between dyslexia and colour blindness. Dyslexic writers tend to make more spelling errors than the general population — not because they are less careful, but because the phonological mapping that helps non-dyslexic writers catch slips is less reliable. Spell-checkers are therefore genuinely useful tools for dyslexic writers.

But almost every spell-checker — Word, Google Docs, LibreOffice, Grammarly, browser spell-check — signals errors with red underlines. For readers with red-green CVD on a white background, those underlines range from faint pink to essentially invisible. The tool designed to help dyslexic writers is rendered useless by a second condition.

The fixes available today are patchy. In Microsoft Word, you can change the underline colour per-document through the macro editor, but there is no global UI setting. Google Docs offers no underline colour setting at all. Grammarly's browser extension uses red for errors and blue for style suggestions — the errors are less visible for deuteranopes, though not completely invisible. The most reliable current workaround is to enable spell-check audio feedback when available, or to use a grammar tool that underlines with shape differences as well as colour — a squiggly line vs a straight line — rather than colour alone. See our article on spell checkers and grammar tools for dyslexia for tool-by-tool detail.

Font weight and shape: independent of colour

Here is the good news: font choice is entirely independent of colour vision. Every piece of guidance on dyslexia-friendly fonts applies equally whether or not you have CVD. The weighted-bottom letters in OpenDyslexic, the wide apertures in Atkinson Hyperlegible, the engineered spacing in Lexend — none of these rely on colour perception. They work through shape and form.

If anything, people with the dyslexia-plus-CVD combination benefit more from font and spacing changes than people with dyslexia alone, because they cannot rely on colour cues to compensate. Strong letterform differentiation, generous letter and line spacing, and clear weight contrast between headings and body text all carry more of the readability load when hue cues are unreliable.

On the question of font weight: medium weight (400-500) is generally better than thin (300) for dyslexic readers because the strokes are more distinct. For CVD, this matters too — thin strokes on light backgrounds can appear to recede and may shimmer. A font at weight 400-500 on a cream or warm-grey background is a safe starting point for both conditions.

Colour-based navigation cues: use shape too

Many websites use colour to communicate meaning — red for errors, green for success, orange for warnings. For CVD readers this creates specific confusion. Red and green error states look identical under protanopia and deuteranopia. An "error" banner and a "success" banner that differ only in background colour are genuinely indistinguishable for about 8% of male visitors.

This is actually a web design problem as much as a personal coping problem — and the solution is the same: never use colour as the only visual cue. Error states should also carry an icon (a cross or exclamation mark), a distinct border shape, or a text label. For dyslexic readers, this redundancy is also useful because clear structural cues reduce the cognitive overhead of parsing the page.

If you are setting up your own reading environment rather than designing for others, the relevant setting is your operating system's colour filters. macOS, Windows, iOS, and Android all offer colour filter overlays in their accessibility settings — typically greyscale, red-green, and blue-yellow modes. Enabling greyscale as a test lets you check whether a web page or document is readable without any colour information at all. If it is, it will work for all CVD types. If it falls apart, colour is doing too much work on that page.

Tinted overlays: proceed carefully

Tinted overlays — the Irlen-syndrome approach of placing a coloured transparent sheet over text — are a common dyslexia recommendation. The idea is that a specific hue reduces the particular visual stress pattern for a given reader. Some people report significant relief; the research base is contested but not negligible. We cover the background in our article on Irlen syndrome and tinted overlays.

For readers with CVD the overlay question becomes more complicated. A red overlay and a green overlay may appear nearly the same hue to a deuteranope. If you are trying to find your personal "best" overlay colour through trial and error — the standard Irlen approach — your colour discrimination in the affected range is not reliable enough to guide the search. In this case, a better strategy is to test overlays that sit outside your confusion range. For the most common red-green CVD types, blue and yellow overlays are distinguishable from each other and from neutral grey. Testing those systematically is more likely to reveal a preference than testing green vs olive vs red vs orange, which may all look similar.

Browser-based overlay tools (extensions that tint the entire page) are useful for this. You can apply a blue tint, read for five minutes, apply a yellow tint, read for five minutes, apply pale grey, and compare comfort. The hue does not matter if you cannot perceive it; the luminance change does.

Dark mode: safe, with caveats

Dark mode — light text on a dark background — is generally well-tolerated by people with CVD because it relies on luminance reversal, not hue. The contrast between light grey or white text and a dark navy or charcoal background is preserved across all common colour vision deficiency types.

For dyslexic readers, dark mode is more variable. Some find it reduces visual stress; others find that light text on a dark background causes more halos and drift than the reverse. The evidence on dark mode and dyslexia doesn't point strongly in either direction — personal preference is the guide here. If you have CVD and dyslexia, dark mode is a safe experiment: it will not disadvantage your colour vision and may or may not help your reading. Use a mid-dark background (not pure black) and off-white text (not pure white) to avoid the extreme contrast that can cause halation in either direction.

What to watch for in dark-mode colour schemes: some dark interfaces use red or green as accent or highlight colours on dark backgrounds. These can be invisible or confusing under CVD. A link in bright red on dark grey is a common failure. If you are configuring a dark-mode theme in an app that allows customisation, choose blue or violet as the accent colour — both sit outside the most common confusion axes.

Practical setup in the browser

For everyday web reading, the most practical approach for the dyslexia-plus-CVD combination is to handle font and spacing separately from colour.

For font, LexiFont lets you apply a dyslexia-friendly typeface — OpenDyslexic, Lexend, or Atkinson Hyperlegible — to every website in Chrome with a single click. The font change is independent of any colour setting, so it layers cleanly on top of whatever colour configuration you use. The LexiFont Pro tier also lets you adjust letter spacing and line height per site — useful if you find that tighter spacing on some sites causes letters to crowd.

For colour, Chrome's built-in high-contrast mode (Settings > Appearance > Force Dark) or an operating-system colour filter gives a system-wide baseline. For per-site colour control, a CSS user-stylesheet or a background-colour extension can override specific sites that use problematic colour schemes.

The combination that works for most readers in this overlap: a warm or pale-grey background, a dyslexia-friendly font at weight 400-500, generous line spacing (1.5x or more), and blue or violet as the accent colour where you have any choice. Avoid relying on any red-green colour distinction to carry meaning in your reading environment.

A note on diagnosis

Colour blindness is significantly under-diagnosed in adults who went to school before colour vision screening became routine. If you have dyslexia and have always found that "cream backgrounds help but not as much as everyone says" or that grammar tool underlines are hard to see, it is worth doing a quick online Ishihara plate test — not for a formal diagnosis, but to check whether CVD might be part of your reading picture. A positive result there changes which accommodations are worth pursuing first.

Similarly, dyslexia is sometimes under-recognised in people who were primarily identified as colour blind in childhood, because a second label was not sought once one explanation existed. If colour blindness doesn't fully explain your reading difficulties — if letters also reverse, words blur, or reading exhausts you disproportionately — it's worth discussing a dyslexia screening with a specialist.