Table of contents
Introduction
The HRR color vision test is widely regarded as one of the most comprehensive tools for detecting and classifying congenital color vision deficiencies. Unlike the well-known Ishihara test, the HRR test offers significant clinical benefits, including tritan detection and more detailed severity grading. The National Eye Institute notes that accurate classification of color vision loss is essential for understanding functional limitations, making HRR a valuable diagnostic choice for both paediatric and adult patients.
Overview of the HRR Color Vision Test
Originally developed decades ago, the HRR test was re-engineered in 2002 to enhance its diagnostic reliability. The redesign included improved colorimetric modelling, more precise placement of colors along confusion lines and refined plate sequencing. These enhancements help providers achieve accurate results under everyday clinical conditions. Unlike the Ishihara, which primarily focuses on red–green defects, the HRR test includes specific plates for tritan (blue–yellow) deficiencies. According to the American Academy of Ophthalmology, tritan defects can indicate underlying ocular or neurological conditions, making their detection clinically important.
How the HRR Test Works
Unique Design and Re-Engineering
The HRR plates use carefully engineered colored dots arranged against grey backgrounds. Each symbol lies close to a protan, deutan or tritan confusion line, allowing subtle differences in color discrimination to be detected. The 2002 Good-Lite HRR edition refined symbol saturation and plate order so that mild, medium and strong defects can be graded more consistently and so that dichromats are more reliably identified as having severe loss.
Detection of Tritan Defects
A major advantage of the HRR system is its ability to detect tritan defects, which may be associated with retinal disease, systemic conditions or certain medications. Because Ishihara lacks tritan plates, relying on it alone can leave important conditions undiagnosed. HRR's re-engineered tritan plates align more closely with actual confusion lines, resulting in improved detection accuracy and a more complete color vision profile for the patient.
Clinical Performance of the HRR Test
Sensitivity and Specificity
Clinical validation shows that the HRR test delivers exceptional accuracy. When using the standard fail criterion of two or more errors on screening plates, the test achieves a 100% sensitivity, meaning all participants with a color vision deficiency were correctly identified. When threshold criteria are adjusted to three or more errors, the test produces a specificity of 100%, ensuring that individuals with normal color vision are not misclassified. These outcomes outperform many traditional pseudoisochromatic tests and align with best practices recommended by leading vision health organisations such as Prevent Blindness.
Comparison with the Ishihara Test
While the Ishihara test remains widely used due to its simplicity, it has known limitations. Most notably, Ishihara plates cannot detect tritan deficiencies, and they provide minimal insight into the severity of color vision impairment. In contrast, the HRR test correctly classifies protan and deutan defects in 86% of cases, with only 3% incorrectly classified. This makes HRR more suitable for occupational screenings where precision matters, including aviation, transport and electrical work, where AAO guidance emphasises the importance of accurate type identification.
Severity Grading and Lighting Conditions
The HRR evaluates not only the type of deficiency but also its severity, categorising cases as mild, medium or strong. This is clinically useful when determining whether a patient may struggle with safety-critical tasks or require workplace adaptations. Severity grading can be cross-checked against the Farnsworth D-15 test to build a fuller picture of functional color discrimination. The validation study also showed that the this test performed reliably even under higher-than-recommended illumination levels, making it practical for busy clinics and school or workplace screening environments.
When to Use the HRR in Practice
Clinical and Occupational Use Cases
This test is well-suited for:
- Occupational color vision assessments
- Paediatric vision screening
- Optometry and ophthalmology practices
- Neurological baseline evaluations
- School-based screening programmes
Its combination of precision, tritan detection and severity grading makes it a more complete assessment tool compared to simpler screening methods. For educators, clinicians and employers, the HRR provides insight into how color deficiencies may affect daily function or job performance.
Recommended Good-Lite Products
For clinics seeking HRR-compatible tools, Good-Lite offers several high-quality options that integrate seamlessly into color vision testing protocols:
Conclusion
The HRR color vision test offers one of the most complete and accurate approaches to color vision assessment. Its high sensitivity, classification accuracy and ability to detect tritan defects give it a significant advantage over traditional methods like the Ishihara test. For clinicians, occupational health teams and paediatric vision screeners, this color test remains a top choice for comprehensive, evidence-based color vision evaluation that aligns with modern clinical standards and international guidance.
