What does a shortened NPC break distance indicate about convergence ability?

What does a shortened NPC break distance indicate about convergence ability?

• A. Weaker convergence
• B. Normal convergence
• C. Stronger convergence
• D. No information about convergence

Answer: (C)

Near point of convergence measures how close a target can get before the eyes can no longer maintain single, fused vision as they converge inward. The break distance is that point of loss of fusion. If this distance is shortened, it means the eyes can converge to a very near point and still maintain single vision, which reflects stronger convergence ability. In other words, the vergence system is capable of generating the necessary inward turn at a closer distance. A longer break distance would indicate weaker convergence, and a normal or unchanged break distance would reflect typical functioning. So a shortened NPC break distance best indicates stronger convergence.

Near point of convergence measures how close a target can get before the eyes can no longer maintain single, fused vision as they converge inward. The break distance is that point of loss of fusion. If this distance is shortened, it means the eyes can converge to a very near point and still maintain single vision, which reflects stronger convergence ability. In other words, the vergence system is capable of generating the necessary inward turn at a closer distance. A longer break distance would indicate weaker convergence, and a normal or unchanged break distance would reflect typical functioning. So a shortened NPC break distance best indicates stronger convergence.