Rapid quantification of color vision: the cone contrast test.
OBJECTIVE
To describe the design, specificity, and sensitivity of the cone contrast test (CCT), a computer-based, cone-specific (L, M, S) contrast sensitivity test for diagnosing type and severity of color vision deficiency (CVD).


METHODS
The CCT presents a randomized series of colored letters visible only to L, M or S cones in decreasing steps of cone contrast to determine L, M, and S letter-recognition thresholds. Sensitivity and specificity were determined by retrospective comparison of CCT scores to anomaloscope and pseudoisochromatic plate (PIP) results in 1446 applicants for pilot training.


RESULTS
CVD was detected in 49 (3.4%) of 1446 applicants with hereditary red-green (protan or deutan) CVD detected in 47 (3.5%) of 1359 men and blue-yellow (tritan) in 2 of 1446. In agreement with the anomaloscope, the CCT showed 100% sensitivity for detection and categorization of CVD (40 deutan, 7 protan, 2 tritan). PIP testing showed lower sensitivity (80% detected; 20% missed) due in part to the applicant's prior experience and/or pretest preparation. CCT specificity for confirming normal color vision was 100% for L and M cone tests and 99.8% for S cones.


CONCLUSIONS
The CCT has sensitivity and specificity comparable to anomaloscope testing and exceeds PIP sensitivity in practiced observers. The CCT provides a rapid (6 minutes), clinically expedient, measure of color vision for quantifying normal color performance, diagnosing type and severity of hereditary deficiency, and detection of acquired sensitivity loss due to ocular, neurologic, and/or systemic disease, as well as injury and physiological stressors, such as altitude and fatigue.
Aerospace Ophthalmology Branch, United States Air Force School of Aerospace Medicine, Brooks City-Base, Texas, USA. rabin@uiwtx.edu
Jeff
J
Rabin
John
J
Gooch
Douglas
D
Ivan
D000337:Aerospace Medicine; D003119:Color Perception Tests; D055253:Color Vision / Q000502:physiology*; D003117:Color Vision Defects / Q000175:diagnosis* / Q000503:physiopathology; D015350:Contrast Sensitivity / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D015203:Reproducibility of Results; D017949:Retinal Cone Photoreceptor Cells / Q000502:physiology*; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D055815:Young Adult