See designs under deuteranopia, protanopia, tritanopia, and achromatopsia. Upload an image or URL. Free Ishihara, D-15, and FM-100 screens live on their own pages—no signup.
Vision screens: Ishihara test · Farnsworth D-15 · FM-100
Simulate protanopia, deuteranopia, tritanopia, and complete achromatopsia with scientifically accurate color shifts.
Upload images, screenshots, or enter a website URL to see instant results — no account required.
Real-time previews powered by advanced rendering ensure your accessibility checks don’t slow you down.
Check if your colors meet the Web Content Accessibility Guidelines for contrast and visibility.
Use our free tools in three steps — whether you’re checking your own vision or testing a design for WCAG accessibility compliance.
Step through 18 color plates. Each shows a number hidden in colored dots — visible differently based on your color vision. Results in under 2 minutes, no sign-up needed.
Start the Free Test →Upload any image or enter a website URL to preview how it looks under protanopia, deuteranopia, tritanopia, or achromatopsia — instantly, in the browser.
Open the Simulator →Identify color-coded elements that fail for CVD users. Adjust your palette and verify contrast ratios meet WCAG 2.2 criteria 1.4.1 and 1.4.3.
Check Your Contrast →Approximately 8% of men and 0.5% of women worldwide have some form of CVD. Each type affects color perception differently — take a dedicated test to identify yours.
Green-Blind
Greens and reds appear as yellows or browns. The most prevalent form of red-green color blindness, affecting roughly 1 in 12 men.
Test for Deuteranopia →Red-Blind
Reds appear very dark or near-black. Common confusion between red, brown, and green. Affects approximately 1% of males.
Test for Protanopia →Blue-Blind
Blues appear greenish and yellows shift toward pink or red. A rare condition affecting roughly 1 in 10,000 people.
Test for Tritanopia →Complete Color Blindness
All colors perceived as shades of grey. Extremely rare (1 in 30,000) and often accompanied by light sensitivity.
Test for Achromatopsia →Approximately 300 million people worldwide have some form of color vision deficiency — roughly 8% of all men. Color accessibility is not optional; it is a legal requirement under WCAG 2.2 (criteria 1.4.1 and 1.4.3) for most digital products.
Suspect you may have CVD? Take the free Ishihara test for a fast, private screening — no sign-up, no download, results in under 2 minutes.
Take the Test →Upload images or enter any website URL to simulate all four CVD types in real time. Catch accessibility issues before they reach production.
Open the Simulator →Verify WCAG 2.2 compliance with the built-in contrast checker. Document CVD simulation results as evidence for accessibility audits and reports.
Check WCAG Contrast →Learn how color vision deficiency impacts hiking, fishing, climbing, and team sports. Real solutions and gear recommendations for outdoor enthusiasts with CVD.
Read Guide →Plain-English guide to S/M/L cones, why red-green CVD is common, and what that means for your Ishihara results and accessible design choices.
Read Guide →Online screening is a start—not a diagnosis. Learn when results warrant an optometrist or specialist, red flags, and what professional CVD testing usually involves.
Read Guide →Simulator accuracy, CVD types, and where the free screening tests live.
DeficiencyView is a free browser toolkit: a Machado 2009 color blindness simulator for images and live URLs, WCAG contrast checks, and optional vision screens. The 18-plate Ishihara-style test is at /color-blind-test. Arrangement formats are D-15 and FM-100. No account required.
The four clinically recognized types are: Deuteranopia (green-blind) — the most common form, greens and reds appear as yellows; Protanopia (red-blind) — reds appear very dark or black; Tritanopia (blue-blind) — blues appear greenish, yellows shift pink; and Achromatopsia (complete color blindness) — all colors are perceived as shades of grey.
The Ishihara-style 18-plate screen is the color blind test page — free, no signup, under two minutes. Designers should start with the simulator on this homepage instead.
Simulations use the Machado, Oliveira & Fernandes (2009) transformation matrices. Processing runs in your browser. Online vision screens are not a clinical diagnosis—see an optometrist for that.
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