Astigmatism
Also known as: Irregular cornea, Blurred vision (refractive)
Astigmatism is a common and usually harmless imperfection in the curvature of the eye's cornea or lens. Instead of being shaped like a perfectly round ball, the front of the eye is curved more like a football, so light focuses on more than one point on the retina. The result is blurred or distorted vision at all distances, along with eye strain and headaches. Astigmatism frequently occurs alongside nearsightedness or farsightedness and is easily corrected with glasses, contact lenses, or refractive surgery.
Symptoms
Causes
- Irregular curvature of the cornea (corneal astigmatism)
- Irregular shape of the lens inside the eye (lenticular astigmatism)
- Present at birth in most cases
- Eye injury, surgery, or the corneal disease keratoconus
Risk Factors
- Family history of astigmatism or other refractive errors
- Being born with the condition
- Keratoconus or corneal thinning
- Previous eye surgery or injury
- Coexisting nearsightedness or farsightedness
Diagnosis
- Comprehensive eye examination
- Visual acuity test reading an eye chart
- Refraction assessment to determine the corrective lens prescription
- Keratometry or corneal topography to map the curvature of the cornea
Treatment
- Eyeglasses with cylindrical lenses to correct the uneven curvature
- Toric contact lenses designed for astigmatism
- Rigid gas-permeable or specialty lenses for higher or irregular astigmatism
- Laser refractive surgery (LASIK, PRK) to reshape the cornea
- Orthokeratology (overnight corneal-reshaping lenses) in select cases
Prevention
- Astigmatism usually cannot be prevented because it is present from birth
- Regular eye exams allow early detection and correction
- Protecting the eyes from injury can prevent acquired astigmatism
- Prompt evaluation of conditions like keratoconus can limit progression
When to See a Doctor
- Blurred or distorted vision that interferes with daily activities
- Frequent headaches or eye strain
- A noticeable change in your vision
- Children showing signs of squinting, eye rubbing, or difficulty seeing the board at school
Frequently Asked Questions
Related Conditions
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