Lazy eye, medically termed “amblyopia”, is poor vision that results from interruption of normal visual development during early childhood. This can occur even when there is no problem with the structure of the eye.
Critical visual development occurs prior to ages seven to eight. If the brain receives only blurry images from the weak eye during this period, it would be difficult to improve vision in that eye after brain development is complete. The eye is then said to be “amblyopic” or “lazy”.
Generally, no. However, if due to high readings of refractive error, the child may go up to close to objects to see better. If due to strabismus, the misalignment may be noticed by friends or family. Droopy eyelids, if obstructing vision can also lead to lazy eye.
Often, the lazy eye may not be detected especially if unilateral, as the other eye often has good vision and the child may not complain of difficulty seeing. Do seek help if the child complains of poor vision, is unable to function well in school, fails a school vision screening test or is noticed to have eyes which are not well-aligned.
Glasses may correct the problem somewhat, but it may not correct it all the way to 6/6 or 20/20. As the brain is used to seeing blurry, it cannot fully interpret the clear image that glasses produce. Except in the mildest cases, patching of the good eye is often required to make the lazy eye work harder.
The initial step would be to prescribe spectacles for refractive errors, treat the squint, or offer surgery for more serious cases of childhood cataracts or droopy eyelids. Subsequently, preventing the use of the better eye with an adhesive patch while enforcing the use of the lazy eye for substantial periods of time is the mainstay of treatment. The child needs to be followed-up while patching until there is no further vision improvement.
Success of treatment depends on the severity of the lazy eye, the age when treatment is started and compliance with prescribed treatment. In general, the earlier the lazy eye is detected, the better the outcome from treatment.
Amblyopia is treatable during the sensitive period of childhood. The limits of this period are still being defined but in most cases, the ages of seven to eight are taken as the onset of visual maturity. However if treatment such as patching has never been initiated, even children older than ages seven or eight have experienced vision improvement after treatment.
Yes. When there is an equal or substantial amount of vision impairment (eg: due to high refractive error), both eyes may be amblyopic.
No, as long as the child is utilizing his/her eyes (i.e. not sleeping). However, watching TV, reading or allowing a child’s favourite activity while patching may encourage compliance.
Occasionally, to encourage compliance, the ophthalmologist may elect to penalize the good eye with eye drops or altering the glasses prescription of the good eye.
This may last from weeks to months or years, depending on the severity of the vision impairment, age of the child and compliance with treatment.