The Px is seeing 1 image (S=0) because the anomalous point (A) and objective strabismus (H) are the same.
Be careful, you do NOT want to break down suppression of HARC patients because you will induce diplopia.
Project the ophthalmoscope's grid pattern onto the fovea and ask the Px to look at the center. This measures eccentric fixation. Normal: fovea is in center of rings. Abnormal: Fovea is in nasal (this is temporal ef, using temporal retina to see), or fovea is temporal
If Bagolini glasses are fused, then do Douse test. Cover the good eye and see if the other see moves. If the other eye moves, then this is HARC.
Typical Unharmonius ARC
The anomalous point (A) is less than the objective strab (H) so the patient sees double (S=H-A).
Atypical Paradoxical II unharmonius ARC
"Angle S is > Angle H because Angle A is in the wrong direction" This is commonly due to overcorrection of the strab beyond the fovea. And so the Px sees double. S=H-A
Atypical Paradoxical I unharmonious ARC
"Angle S is opposite sign of Angle H because Angle A is too large" S=H-A
angle of anomaly “A”
angle between the fovea and the retinal point which has the same directional value as the fovea of the other eye
objective angle of the strabismus “H”
angle between the fovea and the object of fixation
subjective angle of the strabismus “S”
angle between the anomalous point and the object of fixation