Astigmatism is a common vision condition affecting how the eye processes light, leading to blurred or distorted vision. While often present from birth, astigmatism can also develop or change significantly in adulthood. Understanding its nature and potential adult onset helps individuals recognize symptoms and seek appropriate care.
What is Astigmatism?
Astigmatism is a refractive error where the eye’s cornea (the clear front surface) or lens inside the eye has an irregular curve. Instead of being perfectly round like a basketball, the affected eye’s surface is shaped more like a football or the back of a spoon. This irregular shape causes light entering the eye to bend unevenly, preventing it from focusing properly on the retina. Unlike nearsightedness or farsightedness, astigmatism affects vision at all distances.
There are two main types: corneal astigmatism, occurring when the cornea has mismatched curves, and lenticular astigmatism, resulting from a distortion in the eye’s lens. Approximately one in three people have this condition.
Why Astigmatism Develops in Adulthood
While astigmatism is frequently congenital, it can emerge or worsen during adulthood due to several factors. Natural aging processes contribute to changes in the eye’s shape, as the cornea can subtly shift and become more oblong over time. The eye’s lens may also become less flexible with age, leading to increased astigmatism.
Eye injuries or certain eye surgeries can also induce or alter astigmatism. Trauma to the eye can directly affect the cornea’s curvature, and complications after procedures like cataract surgery or corneal transplants may lead to new or increased astigmatism.
Specific eye diseases are another cause of adult-onset astigmatism. Keratoconus, a condition where the cornea progressively thins and bulges outward into a cone shape, is a notable example that can worsen astigmatism.
Signs of Adult-Onset Astigmatism and Diagnosis
Adults developing astigmatism often notice a range of visual symptoms that prompt them to seek an eye examination. Common indicators include blurred vision, especially at night, difficulty seeing fine details, eyestrain, headaches, and a tendency to squint. These symptoms can significantly interfere with daily activities and night driving.
Diagnosis typically involves a comprehensive eye exam performed by an optometrist or ophthalmologist. This examination includes a visual acuity test to assess vision sharpness, and a refraction test to determine the precise lens prescription. Additionally, keratometry or corneal topography is used to accurately measure the cornea’s curvature, essential for diagnosing the type and degree of astigmatism.
Treatment Options for Astigmatism
Correcting astigmatism in adults typically involves several effective methods aimed at improving vision clarity and comfort. Corrective lenses, such as eyeglasses, are a common and non-invasive approach, featuring cylindrical lenses designed to compensate for the eye’s uneven shape and properly refract light onto the retina.
Contact lenses, especially toric lenses, are another popular option. Toric lenses are specifically shaped with multiple curves to correct the irregular astigmatic eye and maintain proper orientation for clear vision.
For those seeking a more permanent solution, refractive surgery can reshape the cornea to correct the astigmatism. Procedures like LASIK (Laser-Assisted In Situ Keratomileusis) and PRK (Photorefractive Keratectomy) use lasers to precisely sculpt the corneal surface, reducing or eliminating the need for glasses or contacts. While LASIK involves creating a corneal flap, PRK reshapes the surface after removing the outermost layer of the cornea.
Other surgical options, such as corneal implants or cross-linking, may be considered for severe cases or underlying conditions like keratoconus.