What Is Astigmatism? Astigmatism is a common refractive error that affects how your eye focuses light. Unlike perfect vision, where light enters the eye and focuses evenly on the retina, astigmatism occurs when the cornea or lens is irregularly shaped. This irregular curvature causes light to scatter unevenly, leading to blurred or distorted vision at all distances. Astigmatism often occurs in combination with myopia (nearsightedness) or hyperopia (farsightedness) and can vary in degree. While it is not a disease, it can significantly impact daily activities such as reading, driving, and using digital devices if left uncorrected. What Causes Astigmatism? The primary cause of astigmatism is the abnormal shape of the cornea or lens. A healthy cornea has a smooth, spherical curve like a basketball. In astigmatism, the cornea is shaped more like a rugby ball—steeper in one direction and flatter in another—resulting in uneven refraction of light. Contributing factors include: Genetics: Astigmatism often runs in families and can be present from birth. Eye injuries or surgeries: Trauma or surgical procedures can alter the corneal shape. Keratoconus: A progressive condition that thins and bulges the cornea. Eyelid pressure: Chronic pressure on the cornea, such as from sleeping habits or frequent eye rubbing. Symptoms of Astigmatism People with mild astigmatism may not notice symptoms. As the condition progresses, the following signs may appear: Blurry or distorted vision at near and far distances Eyestrain or discomfort after reading or screen time Headaches, particularly in the forehead or brow area Squinting to see clearly Difficulty seeing at night Astigmatism can affect one or both eyes and may be symmetrical or more pronounced in one eye. Types of Astigmatism Corneal Astigmatism Caused by an irregular curvature of the cornea, which affects how light enters the eye. Lenticular Astigmatism Results from imperfections in the shape of the eye’s lens rather than the cornea. Regular vs. Irregular Astigmatism Regular: The principal meridians are perpendicular; most common and correctable with glasses or contact lenses. Irregular: Often due to injury or keratoconus and may require specialty lenses or surgical correction. Diagnosing Astigmatism at Bangkok Eye Hospital At Bangkok Eye Hospital, we offer precise and comprehensive diagnostic services to determine the presence and severity of astigmatism. These include: Visual acuity tests to measure clarity of vision Refraction testing to determine the corrective lens power needed Keratometry to measure the curvature of the cornea Corneal topography to create a detailed map of corneal shape Wavefront analysis for surgical planning These evaluations are essential before recommending glasses, contact lenses, or refractive surgery like LASIK. Treatment Options for Astigmatism Astigmatism can be effectively corrected with various methods, depending on the degree and type of refractive error: Eyeglasses The simplest and most common form of correction Use cylindrical lenses to compensate for uneven refraction Available in single vision or progressive lens designs Contact Lenses Toric contact lenses designed specifically for astigmatism Provide more natural vision correction by sitting directly on the cornea Available in soft, rigid gas permeable (RGP), or hybrid lens options Orthokeratology (Ortho-K) Special rigid lenses worn overnight to temporarily reshape the cornea Ideal for low to moderate astigmatism LASIK Surgery A popular long-term solution that reshapes the cornea using a laser Particularly effective for regular corneal astigmatism Fast recovery and minimal discomfort Learn more: LASIK for Astigmatism: What You Need to Know PRK (Photorefractive Keratectomy) An alternative for those with thin corneas or who are not LASIK candidates Reshapes the cornea without creating a flap Refractive Lens Exchange (RLE) Suitable for patients over 40 with significant astigmatism and presbyopia Replaces the eye’s natural lens with an artificial intraocular lens (IOL) Can Astigmatism Be Cured? While glasses and contact lenses offer temporary correction, refractive surgery such as LASIK or PRK provides permanent reshaping of the cornea. However, changes in eye shape may occur over time, and regular follow-ups are recommended to maintain optimal vision. Related Services at Bangkok Eye Hospital To ensure complete and individualized care for patients with astigmatism, we offer: Refractive Surgery CenterIncludes LASIK, PRK, and advanced imaging for surgical planning Comprehensive Eye ExamsDetect and monitor astigmatism and other vision problems Corneal Topography and Wavefront AnalysisFor precise diagnosis and custom treatment Contact Lens ClinicExpert fitting for toric lenses and specialty contacts Dry Eye and Ocular Surface ClinicAssists patients whose astigmatism affects or is affected by dry eye Frequently Asked Questions (FAQs) Is astigmatism genetic?Yes, it often runs in families and can be present from birth. Can astigmatism worsen over time?It can change slightly with age, eye strain, or other eye conditions. Regular checkups are recommended. Is LASIK safe for astigmatism?Yes. LASIK is considered safe and effective for correcting most types of regular astigmatism when performed by experienced surgeons. Can children have astigmatism?Yes. Early screening is important, especially if they exhibit symptoms like squinting or poor academic performance.   Do all contact lenses correct astigmatism?No. Only toric lenses or RGP lenses are designed for astigmatism. A professional fitting is essential.