HRR Test

The HRR Test (Hardy-Rand-Rittler) is a common Pseudoisochromatic Plate test that uses shapes instead of numbers, and is considered to have solved several of the problems indicative of the Ishihara Test (Cole 2006), including:

• There are plates that test for Tritan defects, as well as theoretical Tetartan defects
• The plates are more accurate at diagnosing the type of CVD (protan/deutan/tritan)
• The results offer an approximate level of severity (mild, moderate, severe)
• The plates do not require literacy
• The plates are not as easily memorizable

On each plate, there will be 0, 1 or 2 shapes, where the shapes are either a circle, triangle or X. The test starts with 4 demonstration plates, then 6 screening plates. If the screening plates are not answered perfectly, the test progresses to the 14 diagnostic plates. It can detect blue-yellow and red-green CVD and estimate a severity of the defect.

The modern HRR test was developed in 1955 and published by the American Optical Company, who had previously made the AO Pseudoisochromatic Plates beginning in 1940. After 1991, the tests were published by Richmond, thereby being called the Richmond HRR Test. The next edition, published in 2002, saw a major rework (considered a major improvement) by Neitz, Neitz and Bailey (Cole 2006).