Amblyopia, commonly known as “lazy eye,” is a vision development disorder in which one eye fails to achieve normal visual acuity, even when corrective lenses like glasses or contact lenses are used. It’s not a problem with the eye itself in most cases, but rather a disruption in how the brain and the eye work together. Essentially, the brain begins to favour one eye over the other, gradually ignoring the signals from the “lazy” eye, leading to reduced vision in that eye.
This condition typically develops during infancy or early childhood, a critical period for visual development. If left untreated, the brain’s preference for the stronger eye becomes more entrenched, and the vision loss in the weaker eye can become permanent. The visual system, particularly the connection between the eyes and the brain, is highly adaptable in early life. This plasticity is what allows amblyopia to develop, but it’s also what makes early intervention so crucial.
Several factors can lead to amblyopia. One of the most common causes is strabismus, or a “squint,” where the eyes are misaligned. If one eye turns inward, outward, upward, or downward, the brain receives two different images and, to avoid double vision, it suppresses the image from the misaligned eye. Another frequent cause is refractive error, particularly a significant difference in prescription between the two eyes (anisometropia). If one eye is much more long-sighted, short-sighted, or has more astigmatism than the other, the brain will naturally rely on the eye with the clearer image, neglecting the development of the other. Less common causes include cataracts or other opacities in the eye that obstruct vision, preventing a clear image from reaching the brain.
Detecting amblyopia early is paramount. Since young children often don’t complain about their vision (because they don’t know any different), regular comprehensive eye examinations are essential. These checks can identify subtle signs of misalignment or significant refractive errors that might indicate a developing lazy eye. Paediatricians, school nurses, and parents also play a vital role in observing any unusual eye behaviours, such as frequent squinting, head tilting, or an eye that appears to wander.
Treatment for amblyopia focuses on encouraging the brain to use the weaker eye. The most common and effective method is patching, where the stronger eye is covered for several hours a day. This forces the brain to rely on the weaker eye, stimulating its visual pathways and promoting better vision development. Another approach involves using atropine eye drops in the stronger eye, which temporarily blurs its vision, achieving a similar effect to patching without the need for a physical patch. Corrective glasses are almost always prescribed to ensure the best possible clear image is reaching both eyes. In some cases, particularly if the cause is a cataract, surgical intervention may be necessary to remove the obstruction. Vision therapy, a programme of eye exercises, can also be used to improve eye coordination and focusing skills.
Consistency and adherence to the treatment plan are key to successful outcomes. While it can be challenging for both children and parents, the long-term benefits of improved vision are immeasurable. As children grow, the visual system becomes less adaptable, making treatment less effective after the age of 7 or 8, though some improvements can still be made. This underscores the importance of proactive eye care from an early age. If you have any concerns about a child’s vision, consulting an eye care professional without delay is always recommended.
Treatment
Lazy eye can usually be treated successfully as long as it is diagnosed early enough.
The underlying problem causing the lazy eye is corrected first. That might be by wearing glasses to correct a squint.
The child then is encouraged to start using the affected eye again. This is typically done by wearing an eye patch over the stronger eye or by using eyedrops to temporarily impair the vision in the stronger eye.
Regular eye tests for children with an optician are very important in picking up this condition early so that it can be treated effectively.