Refractive errors are among the most common vision problems in childhood. They arise when the eye does not focus incoming light correctly onto the retina, producing a blurred image. In children, refractive errors matter particularly because the visual system is still developing: an undetected or uncorrected refractive error can lead to amblyopia (lazy eye), which becomes harder to treat the later it is discovered.
The eye is too long or its refractive power too strong: distant objects appear blurred, while near objects are seen clearly. Myopia often develops during the school years and frequently increases during growth. Typical signs: the child squints to read the board, or sits very close to the television.
The eye is too short or its refractive power too weak: in theory the image forms behind the retina. Children can often compensate for mild farsightedness by tensing the ciliary muscle (accommodation), so that they see well at first. With stronger hyperopia or sustained compensation, however, headaches, eye strain and squinting can occur. A certain degree of farsightedness is normal in young children and often decreases as they grow.
The cornea or the lens is not curved evenly but has different refractive power along different axes. As a result, images are perceived as distorted at all distances. Mild astigmatism is common and often unremarkable; when more pronounced, the child needs glasses in order to see sharply.
The two eyes have distinctly different refractive values. The eye with the stronger refractive error delivers a blurrier image, which the brain increasingly suppresses, so that amblyopia develops. Anisometropia is particularly deceptive because it is not visible from the outside and children do not complain about vision problems, since they do not notice the difference.
Children rarely mention vision problems of their own accord: they know no other way of seeing. Watch for the following signs:
Visual acuity is tested with age-appropriate eye charts. The exact refractive power of the eye is determined by the ophthalmologist using retinoscopy, an objective method that requires no cooperation from the child. For this the pupils are dilated with eye drops in order to switch off accommodation (near focusing) and establish the true refractive value. The health of the eyes is examined in addition.
Glasses are the most common and most important treatment. They correct the refractive error and allow the eye to project sharp images onto the retina. In children at risk of amblyopia (particularly with anisometropia), consistent correction with glasses is the first and most important step.
In older children and adolescents, contact lenses can be an alternative, particularly with high myopia, anisometropia or sporting activities. In certain cases special contact lenses are used for myopia control.
If a refractive error has already led to reduced vision, glasses alone are often not enough. Occlusion therapy (patching) or atropine penalisation is then started in addition, in order to strengthen the weaker eye.
Refractive errors change as the child grows. The strength of the glasses therefore has to be checked and adjusted regularly. Recommended examination times:
Detecting and correcting refractive errors early protects your child's visual development and supports their learning in everyday life.