astigmatizm

Astigmatizm, also called astigmatism, is a common refractive error caused by an irregular curvature of the cornea or lens. Because of this irregularity, light rays do not converge to a single focal point on the retina, leading to blurred or distorted vision at both distance and near. The condition can be present from birth and may occur alongside myopia or hyperopia.

Types and causes: Regular astigmatizm features two principal meridians with different powers, and the axis is typically measured in degrees. Irregular astigmatizm arises from irregular corneal surfaces or lens changes and is harder to correct with standard lenses. Astigmatizm is often hereditary and can accompany myopia or hyperopia, or develop after trauma, surgery, or corneal disease such as keratoconus.

Symptoms and diagnosis: People may notice blurred vision, eye strain, headaches, squinting, or difficulty with fine detail. Diagnosis is made during a comprehensive eye examination with refraction testing, keratometry, corneal topography, and retinoscopy to determine cylinder power and axis.

Treatment: Corrective lenses are the most common treatment. Toric glasses or contact lenses adjust for the irregular curvature. In many cases, rigid gas-permeable or scleral lenses provide better correction for irregular astigmatizm. Refractive surgery such as LASIK, PRK, or SMILE can reduce dependence on lenses in suitable candidates. Treatment choice depends on type, degree, and eye health. Early detection in children helps prevent amblyopia.

Epidemiology and prognosis: Astigmatizm is one of the most common refractive errors. It can remain stable or change over time. Regular eye exams are recommended to monitor changes and update corrections.