<prompt> Isochromatic chas are used for: March 2008Contrast sensitivityTesting colour visionVisual fields chaingVisual acuity testing  <response>: Ans. B: Testing colour vision Isochromatic chasJapanese Ishihara chas is used for testing colour vision and it largely identifies red-green anomalies. The American Hardy-Rand-Ritler H-R-R test identifies blue-yellow anomalies. 