Yes, astigmatism can affect one eye. This condition arises from an irregular curvature of the eye’s cornea or lens, which impacts how light focuses on the retina. This article explores why astigmatism can affect a single eye, its signs, and how it is managed.
Understanding Astigmatism
Astigmatism is a common vision condition where the eye’s front surface, the cornea, or the internal lens has mismatched curves. Instead of being perfectly round like a basketball, the eye’s shape is more like a football or the back of a spoon. This irregular shape causes light rays entering the eye to bend unevenly, leading to multiple focal points instead of a single, sharp focus on the retina. As a result, vision can appear blurry, fuzzy, or distorted at all distances.
Why Astigmatism Can Affect One Eye
Astigmatism can develop in one eye but not the other due to various factors, including genetics, eye injury, eye disease, or developmental differences. While often present at birth, experts do not fully understand why the cornea or lens shape varies between individuals or how it can differ between eyes.
Eye injuries or previous eye surgeries can also alter the shape of the cornea in one eye, leading to astigmatism. For instance, keratoconus is a condition where the cornea progressively thins and bulges outward into a cone shape, causing irregular astigmatism. Although keratoconus typically affects both eyes, it can impact one eye more severely than the other, leading to significant vision differences. In some cases, uneven pressure on the eye during development might contribute to asymmetrical corneal changes.
Identifying Symptoms and Diagnosis
Symptoms of astigmatism can vary, but they often include blurry or distorted vision. When astigmatism affects only one eye, symptoms might be subtle or confusing, as the unaffected eye may compensate for the vision deficit. Common indicators include eyestrain, headaches, difficulty seeing at night, and frequent squinting. Children might not realize they have blurry vision and may not complain, making early childhood eye screenings important.
A comprehensive eye exam is necessary for diagnosis. This involves several tests. A visual acuity test measures how sharply a person sees at different distances. A refraction test uses a phoropter to determine the precise lens prescription needed for clear vision. Additionally, a keratometer measures the curvature of the cornea, and corneal topography may be performed to map the corneal surface for any irregularities or distortions.
Correcting Astigmatism in One Eye
The goal of correcting astigmatism is to improve vision clarity and overall eye comfort. Treatment options counteract the uneven curvatures of the cornea or lens, even when only one eye is affected. Eyeglasses are a common first-line treatment, with lenses specifically designed to compensate for the irregular eye shape, ensuring light bends properly onto the retina. These lenses can also correct for other refractive errors present in the same eye, such as nearsightedness or farsightedness.
Contact lenses also provide effective correction for astigmatism. Toric contact lenses are specifically designed to correct astigmatism. For more severe or irregular astigmatism, rigid gas permeable (RGP) lenses may be recommended, as they create a smooth, spherical surface over the eye.
Refractive surgery offers a more permanent solution by reshaping the cornea with a laser. Procedures like LASIK (Laser-Assisted In Situ Keratomileusis) and PRK (Photorefractive Keratectomy) can effectively correct astigmatism. The choice of correction depends on individual needs, the severity of the astigmatism, and lifestyle, and should always be determined in consultation with an eye care professional.