How to prescribe glasses for hyperopia combined with astigmatism of −4.00 D?
Aug 03, 2022
Source: Cainiu Health
Dr. Chen You
Introduction
If hyperopia and astigmatism occur during childhood, a thorough ophthalmic examination must be conducted at a hospital, including visual acuity testing, slit-lamp examination, refraction testing, and fundus examination. If the child has amblyopia—and other causes of amblyopia have been ruled out—cycloplegic refraction using atropine and subsequent refraction testing must be repeated. Following cycloplegia, the measured degree of hyperopia typically decreases by approximately 100–150 degrees.
Many children neglect eye care in daily life, spending excessive time playing video games or using tablets and smartphones—leading to various vision problems such as myopia, hyperopia (farsightedness), and astigmatism. Consequently, parents are deeply concerned about their children’s hyperopia and astigmatism, as these conditions can significantly impair visual function. So, how should corrective lenses be prescribed for a child with combined hyperopia and astigmatism totaling 400 degrees?
How to Prescribe Corrective Lenses for Combined Hyperopia and Astigmatism of 400 Degrees
If hyperopia and astigmatism develop during childhood, a comprehensive ophthalmic examination must be conducted at a hospital. This includes visual acuity testing, slit-lamp biomicroscopy, refraction assessment, and fundus examination. If amblyopia is diagnosed—and other potential causes of amblyopia have been ruled out—cycloplegic refraction using atropine is required, followed by standard refraction. Following cycloplegia, the measured degree of hyperopia typically decreases by approximately 100–150 diopters; in cases of mild hyperopia, the reduction may be around 50 diopters. In contrast, the degree of astigmatism usually remains unchanged. Additionally, careful attention must be paid to the conversion between spherical and cylindrical lens powers. Lens prescription should primarily be guided by the child’s visual needs and functional requirements. Therefore, timely and accurate correction of both hyperopia and astigmatism is essential.
If the combined hyperopic astigmatism is only 50 diopters, one may initially trial correction based solely on the spherical (myopic) component, omitting the astigmatic correction. If visual acuity improves with this approach—and the improvement is clinically meaningful—or if visual acuity reaches an adequate level (e.g., ≥0.8), then correction based only on the spherical component may suffice, and the astigmatic component may be omitted. However, if visual acuity falls below 0.8, a modest increase in the prescribed hyperopic astigmatic correction may be warranted for trial wear. In cases where hyperopic astigmatism is relatively high, particularly with against-the-rule or oblique astigmatism—which tend to compromise visual function—adding appropriate cylindrical correction during trial wear often yields superior visual outcomes.
We recommend that patients cultivate healthy visual habits and maintain good ocular hygiene: avoid reading or using mobile phones while lying down; adopt proper posture when reading; and refrain from prolonged near-vision tasks. We hope this information proves helpful.
