Children, like adults, oftentimes need glasses. The need for glasses is determined by the child’s refractive error. There are, essentially, 3 types of refractive errors: myopia, hyperopia and astigmatism. All refractive errors occur due to structural differences in the eye. In order for people to see, images are typically reflected in the front of the eye, or the cornea. In order for the image to be clear, it needs to be reflected to the back of the eye, called the macula.
Myopia, or near-sightedness, occurs when the eye is large. Images are reflected in the front of the eye but because the eye is large, the image ends up in the middle of the eye or in the vitreous. Glasses, contact lenses and LASIK all act to re-direct the image so that it ends up at the macula. The prevalence of myopia in the United States is about 30-40% while in China is close to 95%. There have been many studies done to investigate this increased incidence in China. There is evidence that decreased Vitamin D intake in China has led to the increased prevalence. Culturally, patients in this region do not get enough sunlight that produces Vitamin D. There has been limited evidence as well that prolonged close-up activity can cause increases in myopia. There are 2 recent studies, the “ATOM” studies, that have shown that the use of Atropine .01% drops can decrease progression of myopia. There have been no side-effects to this treatment. This eye drop, however, is not available at commercial pharmacies. It is only available in compounding pharmacies.
Hyperopia, or far-sightedness, is common in children. If present in lower amounts, most children have an adaptive mechanism, called “accomodation,” to focus through their far-sightedness and do not need glasses for this reason. If the hyperopia, however, is large enough, it can interfere with both distance and near vision and glasses can be prescribed. There are also patients who “over-accomodate,” and cross their eyes in the process of focusing through their prescription. These patients need the full amount of correction so that their eyes straighten out.
Astigmatism is another refractive error. This occurs when the eye itself is shaped like a cone or football. Astigmatism in large amounts can distort the vision and cause problems with long-term vision if not corrected.
If you feel your child has a refractive, error, please call our office for an appointment! We’d love to see you.