In a basic exophoria, which finding would you least expect?

In a basic exophoria, which finding would you least expect?

• A. Reduced PFV ranges
• B. Low AC/A
• C. Reduced NRA
• D. Inability to clear plus lenses on BAF

Answer: (B)

Understanding how accommodation drives vergence is key here. The AC/A ratio describes how much convergence is produced for each diopter of accommodation. In a basic exophoria, the eye alignment is maintained by a typical, balanced link between accommodation and vergence, so the AC/A ratio tends to be normal. A low AC/A would mean you get less convergence for the same amount of accommodation, which would throw off this balance and is not what you’d expect in a straightforward exophoric presentation. It implies an accommodative-vergence pattern different from a simple exophoria, making it the finding least consistent with basic exophoria. The other options reflect potential test findings that can occur with fusional vergence or accommodative issues but don’t contrast as directly with the normal accommodative-vergence coupling as a low AC/A does.

Understanding how accommodation drives vergence is key here. The AC/A ratio describes how much convergence is produced for each diopter of accommodation. In a basic exophoria, the eye alignment is maintained by a typical, balanced link between accommodation and vergence, so the AC/A ratio tends to be normal. A low AC/A would mean you get less convergence for the same amount of accommodation, which would throw off this balance and is not what you’d expect in a straightforward exophoric presentation. It implies an accommodative-vergence pattern different from a simple exophoria, making it the finding least consistent with basic exophoria. The other options reflect potential test findings that can occur with fusional vergence or accommodative issues but don’t contrast as directly with the normal accommodative-vergence coupling as a low AC/A does.