Understanding Astigmatism: Causes, Symptoms, and Treatment Options

Have you ever visited an eye specialist and been told that your eye shape resembles that of a football? Or perhaps you've noticed your vision becoming increasingly blurry or difficult to focus? These experiences are common for many individuals affected by astigmatism, a prevalent refractive error impacting approximately 40% of the global population.

Astigmatism occurs when the eye's surface structures do not possess a smooth, spherical shape. Specifically, it affects the cornea—the transparent front part of the eye—and sometimes the lens inside the eye. Normally, the cornea and lens work together to focus light precisely onto the retina at the back of your eye. For clear vision, these structures need to have specific shapes and sizes.

If these surfaces are irregular or asymmetrical, they cause light rays to scatter or focus unevenly, resulting in blurry or distorted images. This condition, known as refractive error, can affect anyone but tends to become more noticeable and develop further as people age.

There are two main types of astigmatism:

• Regular Astigmatism: This is the most common type and generally results from an oval-shaped cornea, similar to an egg or a football. Its causes are partly genetic, though the full reasons why it develops are not entirely understood.
• Irregular Astigmatism: Less common, this form occurs when parts of the cornea become uneven due to scarring, irregular growths, or conditions like keratoconus, where the cornea weakens and thins into a cone-like shape.

Symptoms often include blurry or distorted vision, increased sensitivity to light, shadows, or double vision. These visual disturbances happen because uneven corneal shapes cause incoming light to scatter, preventing it from focusing properly on the retina.

Historically, the understanding of astigmatism dates back to 1727 when Sir Isaac Newton described how irregular surfaces affect light focus. Later, in 1800, scientist Thomas Young, who had astigmatism himself, explained its effect on vision. By 1825, astronomer Sir George Airy proposed that cylindrical lenses could correct this condition, a method still in use today.

Measuring astigmatism involves refraction tests during eye exams to determine the degree of curvature irregularities. Advanced imaging techniques like corneal topography create detailed 3D maps of the cornea's surface, helping in precise diagnosis.

Treatment options depend on the severity and type of astigmatism. Mild cases may require no correction, but as the condition worsens, options include:

• Glasses: Cylindrical lenses are prescribed to compensate for the irregular curvature.
• Contact Lenses: Special toric contact lenses can correct vision more comfortably.
• Laser Surgery: Procedures like LASIK reshape the cornea to improve focusing.
• Orthokeratology (Ortho-K): Hard contact lenses worn overnight temporarily reshape the cornea, allowing clear daytime vision.
• Corneal Transplants: In severe irregular cases, replacing the damaged cornea may become necessary.

In children, untreated astigmatism can interfere with learning and development or lead to lazy eye, especially if the astigmatism is significant. Regular eye check-ups are vital for early detection and management.

Understanding the shape and function of your eyes can help in managing astigmatism effectively. If you experience changes in vision, consult an eye care professional to explore suitable correction options.