Overview
Vision is learned. If one eye sends a blurred or conflicting image during the first years of life, the brain suppresses it and the visual pathway for that eye never develops properly. The eye itself is usually healthy; the problem is in the wiring.
Amblyopia is the leading cause of monocular vision loss in children and young adults. It responds well to treatment in early childhood and progressively less well as the visual system matures, which is why screening before school matters.
What are the common symptoms?
- Often none that a child can report — they have nothing to compare against
- An eye that turns in or out
- Poor depth perception; clumsiness with catching or pouring
- Head tilting or closing one eye
- Failing a vision screening at school
- Squinting or covering one eye to see
What causes it, and who is at risk?
- Strabismus, where the eyes point in different directions
- A significantly different prescription in each eye
- High uncorrected long-sightedness or astigmatism
- Anything blocking vision early on: congenital cataract, a droopy lid
- Premature birth and family history
How is it treated?
Treatment forces the brain to use the weaker eye. It works best young, and it depends almost entirely on consistency at home.
- Correct the underlying problem first — glasses, or surgery for a cataract or lid
- Full-time spectacle correction, which alone resolves a fair proportion of cases
- Patching the stronger eye for a prescribed number of hours a day
- Atropine drops in the stronger eye as an alternative to patching
- Surgery for the eye turn where present
- Regular follow-up to monitor and to prevent the treated eye slipping back
When to get seen quickly
A white reflection in the pupil in a photograph, instead of the usual red-eye, should be checked promptly — it can indicate a cataract or, rarely, a tumour.
This page is general information, not a diagnosis. Only an eye care professional who has examined you can tell you what is actually going on.