When testing NFV at distance, blur should not be expected; if blur occurs, what is the likely explanation?

When testing NFV at distance, blur should not be expected; if blur occurs, what is the likely explanation?

• A. The patient is overminused
• B. The patient has high NRV reserves
• C. The patient has low AC/A
• D. The patient has insufficient convergence

Answer: (A)

NFV at distance is meant to stress the eyes’ ability to diverge without relying on accommodation. Blur during this test indicates that accommodation is being pulled in to clear the distance target, not that the vergence system itself is failing. If a patient is overminused, the minus lenses require more accommodation even for distance, which brings in accommodative convergence (AC/A). That extra convergence reduces the available divergence reserve, so the image can blur or the test can fail to stay single before true divergence limits are reached. In short, blur at distance NFV points to excessive minus power in the correction.

NFV at distance is meant to stress the eyes’ ability to diverge without relying on accommodation. Blur during this test indicates that accommodation is being pulled in to clear the distance target, not that the vergence system itself is failing. If a patient is overminused, the minus lenses require more accommodation even for distance, which brings in accommodative convergence (AC/A). That extra convergence reduces the available divergence reserve, so the image can blur or the test can fail to stay single before true divergence limits are reached. In short, blur at distance NFV points to excessive minus power in the correction.