Astigmatism is a common vision condition that affects many individuals, leading to blurred or distorted sight. This refractive error often causes people to seek solutions for clearer vision. This article explores astigmatism and how various methods, including glasses, address its effects.
What Is Astigmatism
Astigmatism is a common imperfection in the eye’s curvature, causing blurred or distorted vision at all distances. Instead of a perfectly round shape like a basketball, the cornea (the clear front surface of the eye) or the lens inside the eye has an irregular, egg-like curvature, similar to a football. This irregular shape means that light entering the eye does not bend evenly, leading to multiple focal points instead of a single, sharp focus on the retina.
This results in vision that appears hazy or distorted. Astigmatism is a type of refractive error, often occurring alongside nearsightedness or farsightedness. It can be present from birth, and genetics can play a role.
How Glasses Correct Astigmatism
Glasses effectively correct the vision problems caused by astigmatism, though they do not eliminate the astigmatism itself. The specialized lenses in glasses are designed to compensate for the eye’s irregular curvature. This allows light to focus properly on the retina, thereby sharpening vision.
These corrective lenses, known as cylindrical lenses, have different refractive powers along various meridians, unlike standard spherical lenses. They are specifically shaped to bend light in a way that counteracts the uneven bending of light caused by the astigmatic eye. The “cylinder” value in a prescription indicates the power needed to correct this irregular shape, while the “axis” specifies the orientation of the astigmatism, ensuring the corrective power is applied precisely. This correction is effective only while the glasses are worn.
Does Astigmatism Change Over Time
Astigmatism can indeed change over time, although it rarely disappears completely on its own. For many adults, astigmatism tends to be relatively stable, but gradual changes can occur due to the natural aging process of the eye. Changes in the cornea’s shape and the lens’s flexibility as a person ages can influence the degree of astigmatism.
In children, astigmatism can sometimes decrease or increase as their eyes develop. While some mild cases in infants may resolve naturally, regular eye examinations are important. These natural changes are not influenced by wearing glasses.
Other Ways to Address Astigmatism
Beyond glasses, several other options exist to address astigmatism and improve vision. Contact lenses offer another non-permanent corrective method, functioning similarly to glasses but resting directly on the eye’s surface. For astigmatism, specialized “toric” contact lenses are used; these lenses are designed with different powers in specific meridians to correct the irregular curvature and must maintain proper orientation on the eye for clear vision.
For a more lasting solution, refractive surgeries can reshape the cornea to reduce or eliminate astigmatism, lessening the reliance on corrective eyewear. Procedures like LASIK, PRK (Photorefractive Keratectomy), and SMILE (Small Incision Lenticule Extraction) use lasers to precisely alter the corneal tissue. LASIK creates a thin corneal flap to reshape underlying tissue. PRK removes the outer layer of the cornea before reshaping. SMILE removes a small piece of corneal tissue through a tiny incision. These surgical options aim to permanently correct the refractive error, though suitability depends on individual eye health and the degree of astigmatism.