What causes amblyopia (lazy eye)?

1. Refractive errors: This is the most common cause of amblyopia in Singapore. Refractive errors that might result in amblyopia include high myopia, hyperopia, astigmatism or a significant difference in spectacle degree requirements between each eye (anisometropia). When vision is poor in an eye due to refractive errors, the brain ignores that eye and vision will not develop properly.

2. Strabismus: The misalignment of eyes, in which one eye may focus straight ahead while the other turns in, out, up, or downwards. To avoid seeing double, the child's brain may ignore the image from the misaligned eye, leading to amblyopia.

3. Droopy eyelids or early-onset cataract: Blocked vision due to these conditions can cause deprivational amblyopia.