Ishihara Colour Vision Test Interpretation
Pseudoisochromatic plate test for identifying congenital red-green colour vision deficiency. Standard 24-plate test: 17+ correct = normal; 13 or fewer = colour vision deficiency. Important for certain occupations (aviation, driving, certain clinical roles).
Score interpretation
17–24 plates correct — normal red-green colour vision
→ No further colour vision testing required; document result; meets colour vision standards for most occupational requirements
14–16 plates correct — borderline result
→ Repeat under standardised lighting conditions (Illuminant C); consider Farnsworth-Munsell 100 Hue test for detailed classification; refer to optometrist or ophthalmology; may have implications for some occupations (aviation, driving, certain medical/emergency service roles)
0–13 plates correct — red-green colour vision deficiency
→ Refer to optometrist for full colour vision classification (Farnsworth D-15, FM100); advise patient of implications for occupations requiring normal colour vision (UK CAA aviation: severe restriction; DVLA: no restriction for standard driving); genetic counselling consideration (X-linked inheritance); currently no curative treatment but Enchroma glasses may help in some cases
Interpretation bands for the Ishihara Test. Apply clinical judgement and local guidance.
References
- Ishihara S. Tests for Colour-Blindness. 1917. Handaya, Tokyo.
- Cole BL. Assessment of inherited colour vision defects in clinical practice. Clin Exp Optom. 2007;90(3):157–175.
Related
Curated clinical cross-links plus same-class fallbacks.
- Camellia sinensis (sinecatechins) · Topical green tea catechin extract
- Tetracosactide · Synthetic ACTH (short Synacthen test)
- Urea (13C) · 13C-urea breath test
- Indocyanine Green (Intravitreal Chromovitrectomy) · Diagnostic Dye — Vitreoretinal Surgery / ICG Angiography
- Lissamine Green 1% Eye Drops · Vital Dye — Ocular Surface Staining (Dry Eye Diagnosis)
- Adult Upper Airway Obstruction (Stridor) · DAS 2015 unanticipated difficult airway; RCEM
- Epistaxis Management · ENT-UK / NICE
- Acute Otitis Media · NICE NG91 2018
- Tonsillitis and Sore Throat · NICE NG84 2018
- Benign Paroxysmal Positional Vertigo · NICE CG124 / AAO-HNS Guidelines
- Acute Rhinosinusitis · NICE NG79 2017 / EPOS 2020
Decision support only — verify against a current formulary, NICE, or your local guideline before clinical use.