Understanding Astigmatism: Symptoms, Causes, Diagnosis, Treatment Options & Prevention

What is Astigmatism?

Astigmatism is a common eye condition that affects how your eye focuses light. To understand astigmatism, let’s first consider how a healthy eye works. In a normal eye, the cornea (the clear front layer of the eye) and the lens are smooth and evenly curved, similar to the shape of a basketball. This even curvature allows light to enter the eye and focus on a single point on the retina at the back of the eye, resulting in clear vision.

However, in astigmatism, the cornea or lens has an irregular shape, more like that of a football. This irregularity causes light to be focused unevenly on the retina, leading to distorted or blurred vision.

Sign & Symptoms of Astigmatism

  1. Blurred or Distorted Vision: Astigmatism often leads to blurred or distorted vision, both up close and at a distance.
  2. Eye Strain: People with astigmatism may experience eye strain, especially during activities that require focusing, like reading or using digital devices.
  3. Headaches: Astigmatism can cause headaches, particularly after extended periods of visual tasks.
  4. Difficulty Seeing at Night: Night vision may be compromised, leading to halos, glare, or difficulty driving in low-light conditions.
  5. Squinting: Individuals with astigmatism may frequently squint to try to improve focus and clarity.
  6. Eye Discomfort: Some may experience general eye discomfort or dryness.

Causes of Astigmatism

  1. Corneal Irregularities: Astigmatism often results from an irregular shape of the cornea, which should be spherical but may become oblong or oval.
  2. Eye rubbing: eye rubbing is a common cause of astigmatism, and can lead to irregular astigmatism and a condition known as keratoconus.
  3. Lenticular Astigmatism: Less common, it can also be caused by irregularities in the eye’s natural lens.
  4. Genetics: Family history plays a role, increasing the likelihood of developing astigmatism.
  5. Eye Trauma or Injury: Physical injuries, accidents, or surgical procedures can alter corneal shape.
  6. Eye Conditions: Conditions like keratoconus or eye diseases can lead to astigmatism.
  7. Congenital: Some individuals are born with astigmatism, which may become apparent later.
  8. Eye Growth: Changes in the eye’s shape during childhood and adolescence can lead to astigmatism.
  9. Post-Surgery: Astigmatism may develop or worsen after eye surgeries, including cataract surgery.
  10. Eye Pressure: Elevated intraocular pressure, as in glaucoma, can affect corneal shap

Types of Astigmatism

There are different types of astigmatism, including regular and irregular astigmatism. Regular astigmatism is the most common form and occurs when the cornea has two distinct curves, usually at right angles to each other. Irregular astigmatism, on the other hand, is less common and may result from eye injuries, surgeries, or conditions like keratoconus.

Astigmatism is also categorised based on the orientation of the principal meridians:

  1. With-the-Rule Astigmatism: The steepest meridian is vertical.
  2. Against-the-Rule Astigmatism: The steepest meridian is horizontal.
  3. Oblique Astigmatism: The steepest meridian is neither horizontal nor vertical.

Diagnosis

Diagnosing astigmatism is a crucial step in managing the condition.

  1. Visual Acuity Testing: Diagnosis often begins with a visual acuity test, where you read letters or symbols on an eye chart to measure your ability to see at various distances. Patients with astigmatism tend to have reduced visual acuity.
  2. Keratometry: An instrument called a keratometer measures the curvature of the cornea to detect astigmatism.
  3. Refraction Test: A refraction test determines the exact prescription needed to correct astigmatism.
  4. Corneal Topography: This advanced imaging technique maps the shape of the cornea and can identify irregularities contributing to astigmatism.
  5. Regular Eye Exams: Regular eye exams, even when you have no apparent symptoms, are crucial for early detection of astigmatism, especially in children or individuals at higher risk.

Treatment Options for Astigmatism

The good news is that astigmatism can be effectively managed. Treatment options include:

  1. Glasses: Prescription glasses with lenses that compensate for the astigmatism. 
  2. Contact Lenses: Toric contact lenses to correct astigmatism.
  3. Orthokeratology: A non-surgical option involving specialised contact lenses worn overnight to reshape the cornea temporarily.
  4. Laser vision correction: Procedures including LASIK, PRK, and SMILE can reshape the cornea to correct astigmatism.
  5. Lens surgery: Lens based surgery (like cataract surgery) can also correct astigmatism.

The choice of treatment depends on individual preferences, lifestyle, and the severity of astigmatism.

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Astigmatism in Children

Astigmatism can start in childhood. Early detection and treatment are crucial to ensure normal vision development. Paediatric eye exams can help identify and manage astigmatism in kids

Prevention of Astigmatism

While you can’t completely prevent astigmatism, there are some measures you can take to reduce the risk of developing it or to minimise its impact:

  1. Regular Eye Exams: Schedule routine eye check-ups with an eye care professional. Early detection allows for prompt management of any developing astigmatism.
  2. Avoid Eye Rubbing: Refrain from rubbing your eyes vigorously, as this can lead to changes in corneal shape or corneal conditions that might contribute to astigmatism.
  3. Eye Protection: Protect your eyes from injuries by wearing safety glasses or goggles during activities that pose a risk of eye injury, such as sports or home improvement projects.
  4. Monitor Children’s Vision: Pay attention to your child’s visual development, and ensure they receive regular paediatric eye exams. Early detection and intervention can address astigmatism in children effectively.

 

While these measures can promote overall eye health and potentially reduce the risk of some eye conditions, it is essential to remember that astigmatism can also have a genetic component, and some individuals may develop it regardless of preventive efforts.

Living with Astigmatism

Living with astigmatism is manageable with some simple steps:

  1. Follow your prescribed treatment plan, e.g. wearing glasses or contact lenses. 
  2. Maintain regular eye check-ups to monitor your condition.

Conclusion

In conclusion, astigmatism is a common eye condition that affects millions of people worldwide. However, with the right diagnosis and treatment, it can be usually managed very effectively, allowing individuals to enjoy clear vision. If you suspect you have astigmatism or have any questions about your eye health, don’t hesitate to schedule an appointment with Clarity Eye Surgeons in Canberra. Our team of eye surgeons is here to help you see the world with clarity and precision.

Author Bio

Dr Parth Shah is a director and principal ophthalmologist at Clarity Eye Surgeons in Canberra, specialising in cataract surgery and strabismus surgery. With extensive training and experience, he is renowned for his expertise in the field. Dr Shah is dedicated not only to performing successful surgeries but also to patient education. His compassionate approach, combined with technical proficiency, has earned him the trust and gratitude of countless patients. He is a true advocate for eye health and a trusted name in the Canberra ophthalmology community.

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