In vergence testing, what does PFRV stand for?

In vergence testing, what does PFRV stand for?

• A. Positive Frontal Vergence Reserve
• B. Positive Fusional Reserve Vergence
• C. Prism Fusion Reserve Value
• D. Power Fusional Reserve Vergence

Answer: (B)

This item tests what PFRV stands for in vergence testing: Positive Fusional Reserve Vergence. Positive fusional vergence is the system’s ability to converge the eyes (to counter base-out demands) to keep the image single as convergence demand increases. The “reserve” part means the extra fusional vergence capacity available beyond the immediate demand—the buffer that keeps single vision when more convergence is required. In practice, clinicians measure this as the positive fusional vergence reserve, reflecting how much convergence margin a patient has before blur or diplopia occurs. Other terms don’t fit because they use nonstandard descriptors or mix up the type of vergence involved.

This item tests what PFRV stands for in vergence testing: Positive Fusional Reserve Vergence. Positive fusional vergence is the system’s ability to converge the eyes (to counter base-out demands) to keep the image single as convergence demand increases. The “reserve” part means the extra fusional vergence capacity available beyond the immediate demand—the buffer that keeps single vision when more convergence is required. In practice, clinicians measure this as the positive fusional vergence reserve, reflecting how much convergence margin a patient has before blur or diplopia occurs. Other terms don’t fit because they use nonstandard descriptors or mix up the type of vergence involved.