Which statement is NOT a characteristic of a Micro ET?

• A. It is constant and unilateral
• B. It typically has a deviation less than 10 prism diopters
• C. It typically develops after 6 years of age
• D. It is associated with a small central suppression scotoma that can be confirmed using the four base-out prism test

Answer: (C)

Microesotropia is a small-angle, constant inward turning of one eye that typically appears early in life and is tied to central suppression in order to avoid diplopia. The deviation is generally small, often under 10 prism diopters, and it tends to be constant and unilateral rather than alternating. A central suppression scotoma is a hallmark feature, reflecting the brain’s adaptation to suppress input from the fovea of the deviated eye to maintain single vision, and this suppression can be demonstrated with the four base-out prism test, which reveals the central suppression area. Onset after six years of age is not typical for microesotropia, since it usually becomes evident in infancy or early childhood. Therefore, that statement does not fit the usual pattern of microesotropia.