What is the most common type of ARC?

What is the most common type of ARC?

• A. HAC
• B. UHAC
• C. PAC 1
• D. PAC 2

Answer: (A)

Anomalous retinal correspondence (ARC) is a neural adaptation in strabismus where the brain uses a non-foveal retinal point to fuse images and suppress diplopia. The pattern of ARC is largely determined by how much convergence is triggered by accommodation, i.e., the AC/A relationship. The most common form you’ll see is the high AC/A type, where accommodation elicits more convergence than usual. This means near alignment tends to be worse (more esotropia or more inner deviation) than distance alignment, and ARC develops to help fuse images despite that bias. The other patterns—ultra-high AC/A or partial ARC types—occur less frequently, so the high AC/A pattern is the typical presentation for ARC.

Anomalous retinal correspondence (ARC) is a neural adaptation in strabismus where the brain uses a non-foveal retinal point to fuse images and suppress diplopia. The pattern of ARC is largely determined by how much convergence is triggered by accommodation, i.e., the AC/A relationship. The most common form you’ll see is the high AC/A type, where accommodation elicits more convergence than usual. This means near alignment tends to be worse (more esotropia or more inner deviation) than distance alignment, and ARC develops to help fuse images despite that bias. The other patterns—ultra-high AC/A or partial ARC types—occur less frequently, so the high AC/A pattern is the typical presentation for ARC.