How is astigmatism corrected?
Dec 20, 2021
Source: Cainiu Health
Dr. Cui Xin
Introduction
1. During refraction and eyeglass fitting, individuals with high astigmatism must wear toric (astigmatic) glasses.
2. To ensure accuracy in refraction and fitting, it is advisable to undergo an eye examination at a professional optometry center or ophthalmic hospital before proceeding with lens fitting.
3. In addition to conventional framed toric glasses, toric contact lenses have become an effective option for correcting astigmatism.
Astigmatism is a refractive error of the eye associated with the curvature of the cornea. When parallel light rays enter the eye, they fail to converge at a single focal point due to unequal refractive power across different meridians of the eye—resulting in blurred or distorted vision. This condition is termed astigmatism. In astigmatic eyes, neither accommodation nor adjusting the distance between the eye and the object can produce a clear image; only properly prescribed cylindrical lenses enable formation of a sharp image on the retina. So, how is astigmatism corrected? The following section addresses this question.
How Is Astigmatism Corrected?
1. During refraction and spectacle fitting, individuals with moderate-to-high astigmatism must wear toric (astigmatic) spectacles. Even those with mild astigmatism—including frequent computer users, professionals engaged in fine-detail work, or students who read or write extensively—should consider wearing toric spectacles.
2. Unlike simple myopia, astigmatism correction requires precise determination of both the axis and the degree of astigmatism. To ensure accuracy in refraction and lens fitting, it is advisable to undergo comprehensive evaluation at a professional optometry center or ophthalmology hospital before ordering corrective lenses.
3. In addition to conventional framed toric spectacles, toric contact lenses have become an effective option for correcting astigmatism—and offer distinct advantages over traditional spectacles.
Knowledge Extension: Can Increasing Myopia Prescription Correct Astigmatism?
When prescribing spectacles for patients with astigmatism, a common—but incorrect—practice is to subtract half the astigmatic diopter value and add it to the spherical (myopic) component. This approach does not resolve the underlying astigmatism; rather, it artificially increases the myopic prescription. Potential consequences include accelerated progression of myopia, exacerbated ocular discomfort, persistent visual distortion despite improved visual acuity, and symptoms such as headache and eye fatigue.
The above outlines key approaches to correcting astigmatism. We hope this information proves helpful to you.
