What is the MOST likely cause of refractive amblyopia?

• A. Isometropic hyperopia
• B. Anisometropic hyperopia
• C. Isometropic myopia
• D. Anisometropic myopia

Answer: (B)

Refractive amblyopia develops when one eye consistently presents a blurrier image during visual development, leading the brain to suppress that eye to avoid double vision. The strongest risk factor is anisometropia—a difference in refractive error between the eyes. When one eye is significantly more hyperopic than the other, that eye is blurrier at all distances and requires more accommodation; this persistent unequal image quality drives suppression of the blurrier eye and impairs its cortical development. That unilateral suppression is why anisometropic hyperopia is the most likely cause of refractive amblyopia. If both eyes were similarly misfocused (isometropia), you’d expect bilateral rather than unilateral reduced vision, and anisometropic myopia can cause amblyopia too, but the hyperopic difference is the most common scenario.