We say that a child has a lazy eye or suffers from amblyopia when one or both eyes have decreased vision. It is a delay in the development of the visual function that can be due to injuries, diseases of the eye or visual pathway, refractive errors (myopia, hyperopia, astigmatism) or a squint (strabismus).
In the case of damage to the eye, when a child has an injury to an eye, vision in that eye will be temporarily diminished and treatment should be focused on treating the injury. The more the vision is affected and the longer it takes to resolve the problem the more likely it is that the child will develop amblyopia or lazy eye.
However, the most common causes of lazy eye in children are long-sightedness or a squint, which can occur in healthy eyes preventing their proper functioning. Among the refractive errors (myopia, hyperopia and astigmatism), astigmatism is the most likely to result in a child developing a lazy eye, especially when there is a large difference between the strength of both eyes. This makes it important to have children’s eyes checked from an early age, since correcting problems in time will allow normal visual development to take place.
A squint can be another cause of lazy eye. If a child has a deviation in which one eye is aligned while the other deviates, the deviated eye creates a compensation mechanism for this anomalous situation that results in the elimination of the image received from the deviated eye. This is a form of amblyopia by suppression of the image from the deviated eye. There are many types of squint and the most important thing is early detection and treatment in those cases that interfere with the visual process to the greatest extent.
Vision therapy is a set of techniques that are taught and that help in the rehabilitation process of the lazy eye. The therapy works with monocular aspects such as changing focus between distances, maintaining focus, eye movements, hand-eye coordination and it also works with binocular aspects (exercises based on the use of both eyes at the same time) to encourage the simultaneous use of both eyes at the same time thereby strengthening the mechanisms involved in correct binocular vision.
A correct diagnosis is of the utmost importance to be able to differentiate between lazy eye caused by eyes with different strengths or by a squint or visual loss due to organic or pathological causes.