Which type of ET is MOST associated with a small central suppression scotoma that can be diagnosed with a 4 BO prism test?

• A. Infantile ET
• B. Accommodative ET
• C. Consecutive ET
• D. Micro ET

Answer: (D)

Microesotropia involves a very small inward turn of the eyes, so the sensory system often uses central suppression to avoid diplopia. This creates a tiny, central suppression scotoma rather than a broad field suppression. Because the misalignment is so small, it can be easy to miss with routine tests, but a small base-out prism (a few prism diopters) is enough to slightly dissociate the eyes and reveal that the central area of fixation is being suppressed. This pattern—tiny angle deviation with a central suppression scotoma revealed by the 4 BO prism test—is characteristic of microesotropia, distinguishing it from larger infantile esotropia, accommodative esotropia, or a consecutively acquired esotropia, which don’t typically show that specific central suppression pattern.