Which finding indicates reduced PFV ranges?

Which finding indicates reduced PFV ranges?

• A. NFV Ranges
• B. PFV Ranges
• C. Both NFV and PFV Ranges
• D. Normal PFV

Answer: (B)

Positive fusional vergence is the eyes’ ability to converge to maintain single vision as demand for convergence increases. When you test PFV with base-out prisms, you’re measuring how much convergence the patient can sustain before blur or diplopia occurs. A reduced PFV range means the patient cannot converge as much as normal, so the prism amount they can fuse is smaller. This direct finding points to reduced PFV ranges, a sign often seen in convergence insufficiency or related vergence problems. NFV ranges, by contrast, assess divergence, so they indicate a different aspect of binocular function. A normal PFV would mean no reduction in convergence reserve.

Positive fusional vergence is the eyes’ ability to converge to maintain single vision as demand for convergence increases. When you test PFV with base-out prisms, you’re measuring how much convergence the patient can sustain before blur or diplopia occurs. A reduced PFV range means the patient cannot converge as much as normal, so the prism amount they can fuse is smaller. This direct finding points to reduced PFV ranges, a sign often seen in convergence insufficiency or related vergence problems. NFV ranges, by contrast, assess divergence, so they indicate a different aspect of binocular function. A normal PFV would mean no reduction in convergence reserve.