Squint

A squint (strabismus) is a condition in which the two eyes do not look in the same direction. One eye may turn inwards (convergent / esotropia), outwards (divergent / exotropia), upwards, or downwards, either constantly or intermittently. Squint can appear in childhood or develop in adults.

Why does squint matter?

Beyond cosmetic concerns, an untreated squint in a child can lead to amblyopia (lazy eye) — the brain suppresses the image from the squinting eye, and vision in that eye can become permanently reduced if not treated early. Children do not "grow out of" squint; early detection and treatment are essential.

Causes

• Refractive error — especially long-sightedness (hypermetropia) in children
• Family history — squint often runs in families
• Muscle or nerve problems affecting the eye
• Childhood conditions — cerebral palsy, Down syndrome, prematurity
• Injury, stroke, thyroid disease, or diabetes — in adult-onset squint
• Some cataracts or other eye conditions

Symptoms

• Misaligned eyes — visible all the time or intermittently
• Double vision (adults more often than children)
• Eye strain or headaches
• Tilting or turning the head to see clearly
• Closing one eye in bright sunlight (more common in exotropia)
• Poor depth perception

Treatment

Most squints can be treated successfully, especially if caught early. Options include:

• Spectacles — the mainstay of treatment, especially for children whose squint is caused by refractive error
• Patching (covering the stronger eye for a few hours a day) — to make the brain use the weaker eye and prevent amblyopia
• Eye exercises — for certain types of squint
• Prisms in glasses — for small persistent misalignments
• Botulinum toxin injections — for some types
• Surgery — realigns the eye muscles; may be combined with other treatments

Children should have an eye check by age 3-4 (earlier if squint is suspected). Any squint noticed in a child — even if it seems intermittent — warrants a paediatric ophthalmology review.