Amblyopia or "Lazy Eye" is a less talked of but not uncommon condition affecting the vision of eyes.
It is a disorder of visual development in which an eye fails to achieve normal vision even though it otherwise appears normal.
The process starts in infancy or early childhood, hence birth to 2 years is called as the " critical period" of visual maturation. Amblyopia mostly affects only one eye but could affect both eyes.
Depending on cause there are three main types:
- Strabismic amblyopia: this occurs due to misalignment of the eyes (squint). Squint could be the cause or effect of amblyopia.
- Refractive error: Usually when one eye has a high uncorrected refractive error (spectacle number)called "Anisometropic Amblyopia". If both eyes have same high refractive error called as "Isometric amblyopia".
- Stimulus deprivation amblyopia: this develops in conditions like paediatric cataract, ptosis, uncorrected aphakia where visual impulses do not reach the developing eye.
The part of the brain receiving images from the affected eye is not stimulated properly and is suppressed by the normal visual cortex and hence fails to develop to its full visual potential. Diagnosis:
The problem with this condition is that since these children do not complain, it may be missed. A developing squint or if the child cries and refuses occlusion of one eye, it may indicate some problem. The key to treatment is an early diagnosis. This can be done by checking vision by an ophthalmologist. The visual improvement is best below 8 years although up to 12 - 14 years also treatment helps. Newer treatment modalities claim to have benefit even in those up to 33 years. Treatment progresses in a stepwise manner:
- Correction of conditions like ptosis, cataract etc.
- Correction of refractive error
- May need patching (occlusion) or atropine penalisation
- Applied perceptual learning techniques
EARLY DIAGNOSIS IS THE KEY TO SUCCESSFUL TREATMENT. This can be achieved by screening all the children even if there are no complaints.