A patient’s cover test finding is 8 CRXT and their angle of anomaly is -8. What type of correspondence do they have?

• A. HAC (objective = angle of anomaly)
• B. Unharmonious correspondence
• C. PAC 1
• D. PAC 2

Answer: (A)

The key idea is how the brain’s sensory mapping aligns with the eye movements. The angle of anomaly is the amount by which the preferred sensory correspondence (the point on the retina that the brain uses for fusion) is shifted relative to the fovea. When the measured motor deviation on cover testing exactly matches that sensory shift—both in magnitude and direction—you have a harmonious relationship between the objective angle of deviation and the angle of anomaly. This is called HAC.

In this case, the patient shows 8 prism diopters of exotropia on the cover test and an angle of anomaly of -8, meaning the objective deviation equals the angle of anomaly. That alignment indicates HAC.