Amblyopia is the medical term for a ‘lazy eye’. This is where there is reduced vision in an otherwise healthy eye.
There is a sensitive time when the vision is developing in childhood. At this time, if light entering the eye doesn’t fall onto the central part of the retina, there may be a permanent inability to see clearly with that eye.
This most commonly occurs when a child who:
Needs glasses: so the images reaching the retina are not in focus. (Refractive amblyopia)
If the eyes are not straight: such as in strabismus or ‘squint’ so the images do not fall onto the fovea, which is our central and most clear point of vision. (Strabismic Amblyopia)
Or if there is an obstruction to light entering the eye: such as cataract (Deprivation Amblyopia)
Many children do not notice they have a problem with their vision and the parents may not notice any unusual behaviour, especially if the eyes look normal and one eye works well.
All children in this country, will have basic screening of their eyes at birth to ensure there is a good red reflex and to check the eyes are aligned. Most schools still have a vision screening programme, when children are between 4 and 5, as it important to identify any reduced vision as early as possible, so effective treatment can be undertaken.
If there is a family history of a lazy eye or wearing glasses in childhood, it is often worth having a more thorough examination sooner, especially if a child appears to ‘squint’.
The first part of treatment is to correctly diagnose what is causing the reduced vision.
This involves checking the vision in each eye, by an appropriate method for each child. Then a thorough check of the eye, which involves dilating the pupils with drops to have a careful check of the back of the eye. All children will have a ‘refraction’ where glasses may be recommended if necessary.
It is important to encourage the child to use the ‘lazy eye’. This may involve drops or a patch to encourage the weaker eye to work. Occasionally, an operation is need if the eyes are not ‘aligned’ and do not straighten in glasses, or rarely if there is an obstruction to vision entering the eye.
The treatments are usually effective, but can be a gradual process.