Article

PEDIATRIC AND TEEN CL CARE

BENEFITS OF CONTACT LENSES FOR HIGH REFRACTIVE ERRORS

Children benefit from contact lens wear because it improves vision and cosmetic appearance and also helps with self-image. When examining this special population, practitioners should be aware of the benefits that contact lenses have to offer, especially in children who have high spectacle prescriptions. This article will review some of the disadvantages of spectacle wear in children who have high refractive errors.

Induced Prism

Spectacles induce prism when looking away from the optical center. In cases of high hyperopia, base-out prism is induced when the eyes converge while trying to read. This may be problematic in children who experience a high accommodative convergence to accommodation (AC/A) ratio. In hyperopes, the AC/A ratio is actually increased through spectacles in comparison to contact lenses (Sindt, 2006). Thus, contact lenses may be more beneficial to hyperopic children who have accommodative esotropia.

Aniseikonia

Aniseikonia creates a difference of image size on the visual cortex. Symptoms of aniseikonia include eyestrain, headache, blurring, diplopia, suppression, and amblyopia. Unequal image sizes result from either anisometropic refractive error or from differences between the eyes’ axial lengths.

The magnification difference between spectacle-corrected eyes is approximately 2% per diopter of difference. A 3% disparity is often tolerated by individuals; however, a disparity greater than 5% to 7% will impair binocular vision.

In comparison to spectacles, contact lenses are able to decrease the image size disparity created by anisometropia. For example, in the case of unilateral aphakia, contact lenses reduce the amount of magnification change between the two eyes by 60% in comparison to spectacles (Sindt, 2006).

Cosmetics and Comfort

In comparison to spectacles, children who wear contact lenses have better self-image and greater satisfaction in their overall quality of vision with contact lenses (Walline et al, 2009).

In some situations, children will not wear glasses. This may be due to poor function and comfort. Children have small noses with bridges that are difficult to fit with glasses. Additionally, glasses frequently sit crooked on their heads, causing physical and visual discomfort and causing them to look over or to remove the glasses. One 5-year-old girl who has bilateral aphakia due to congenital cataract extraction would remove her glasses because they would not sit straight on her face due to her heavy high-plus prescription (Figure 1). The patient was much more comfortable and could see better through her contact lenses.

Figure 1. High-prescription glasses are physically and visually uncomfortable.

Summary

Children benefit from contact lens wear because it improves vision and cosmetic appearance and also helps with self-image. When examining this special population, practitioners should be aware of the refractive benefits that contact lenses have to offer. CLS

For references, please visit www.clspectrum.com/references and click on document #279.