Amblyopia
Amblyopia is a common cause of reduced vision in children. It is due to disruption of the normal development of vision during childhood. Amblyopia is sometimes also known as 'lazy eye'. Usually one eye is affected, but both may be affected in some cases.
Amblyopia is thought to affect about 3 per cent of children. Most cases can be treated successfully if detected at an early age. However, if it isn’t treated early enough, it can result in permanent vision impairment or blindness in the affected eye.
Causes of amblyopia
Amblyopia most commonly results from either strabismus (squint) or refractive error (long-sightedness, short-sightedness or astigmatism).
Squint
A squint occurs when the eyes point in different directions. This would usually result in double vision or blurred vision. However, to avoid this, a child's brain is able to suppress the image from one eye, causing that eye to become amblyopic or 'lazy'.
Refractive error
If there is a significant difference in the refractive error between the eyes — such as one eye being much more long-sighted than the other — the brain suppresses the image from the weaker eye, causing it to become amblyopic.
If there is a high refractive error in both eyes — such as both eyes being very long-sighted — this may cause amblyopia in both eyes.
Other
Less commonly, amblyopia may be the result of other diseases, such as a congenital cataract (cataract present at birth) or a tumour of the eye.
Amblyopia symptoms
Children with amblyopia are often too young to describe their symptoms. Parents may notice that they cover one eye or that one eye does not look in the same direction as the other (crossing in or turning outwards). Older children may notice they have problems with vision in one eye or with depth perception.
How is amblyopia diagnosed?
Amblyopia can usually be diagnosed by a full examination of the eyes. If you suspect that there is any problem with your child’s eyes, you should consult your doctor. A child is never too young to have their eyes examined.
Because of the importance of early detection, all children should routinely have their eyes tested before school age.
Amblyopia treatment
The treatment for amblyopia depends on the cause.
Prescription glasses
If a refractive error, such as short sightedness, long-sightedness or astigmatism, is contributing to lazy eye, then glasses or contact lenses may be prescribed. These may be enough to correct the problem.
Eye patches
A widely used treatment involves stopping your child using their 'good eye', and forcing them to use their 'lazy eye'. This commonly involves covering the good eye with a patch. An alternative to this is putting eye drops in the good eye which blur the vision.
Surgery
Sometimes surgery is required to correct an imbalance in the eye muscles. A cataract may also require surgical removal.
Orthoptics therapy
Eye exercises (orthoptics therapy) can also help the eyes work together.
The earlier amblyopia is treated, the better the chance that your child will regain normal vision.
Last Reviewed: 12 August 2011
- 1. MayoClinic.com. Lazy eye (amblyopia) (19 Nov 2010). http://www.mayoclinic.com/health/lazy-eye/DS00887 (accessed Nov 2011).
2. Royal Australian and New Zealand College of Ophthalmologists. “Lazy eye” amblyopia (reviewed 20 Nov 2011). http://www.ranzco.edu/index.php/patients/eye-conditions/qlazyq-eye-amblyopia (accessed Nov 2011).
3. Merck Manual. Amblyopia (last reviewed Apr 2006). In: Merck manual home health handbook online version. Whitehouse Station, NJ, USA: Merck Sharp and Dohme; 2009. http://www.merckmanuals.com/home/childrens_health_issues/eye_disorders_in_children/amblyopia.html (accessed Nov 2011).
