Astigmatism

What is Astigmatism?

Astigmatism is a refractive problem that affects how the eye bends or refracts light.

In a healthy eye, the cornea and lens have a smooth, rounded shape that helps focus light clearly on the retina. This enables the light to be focused at a single point on the retina (the light-sensitive layer at the back of the eye) and ensures proper vision.

Astigmatism occurs when the cornea or lens is more curved in one direction than the other, resembling more of a rugby ball than a sphere. Consequently, light entering the eye settles on two points rather than one, leading to blurred or distorted vision at all distances.

Astigmatism is typically either present at birth or may develop later in life. It is often seen in conjunction with myopia (nearsightedness) or hyperopia (farsightedness). Certain eye conditions, such as cataracts, keratoconus and dry eye disease, can affect how astigmatism develops or is treated.

What are the Types of Astigmatism?

The different types of astigmatism include:

How Common is Astigmatism in India?

Astigmatism is a common condition in India. It is often underdiagnosed, especially in children and adults in rural communities with restricted access to routine eye care. A study showed that the overall prevalence of astigmatism in India is about 30%, with 35.2% and 28.8% in rural and urban areas, respectively, which equates to a significant portion of the population.

The prevalence of astigmatism increases with age and is more likely to be higher in groups that have poor access to vision screening and corrective care. In India and globally, increased screen use often aggravates the visual discomfort associated with astigmatism in young people.

What are the Symptoms of Astigmatism?

The symptoms of astigmatism depend on the degree of refractive error. Mild cases may not cause noticeable problems, while moderate to severe astigmatism can interfere with daily activities such as reading, driving, or using digital devices.

Common early warning signs and advanced stage astigmatism symptoms include:

What are the Causes and Risk Factors of Astigmatism?

Common causes and risk factors of astigmatism include:

What are the Severity Levels of Astigmatism?

Astigmatism is usually grouped by severity based on dioptres (D), which is a unit used to measure the focusing power of the eye lens or prescription glasses and how much it affects vision. The astigmatism severity levels and their features include:

Diseases Similar to Astigmatism

Astigmatism shares symptoms with other common refractive errors like myopia and hyperopia. Understanding their differences helps ensure accurate diagnosis and appropriate vision correction. The main differences among these conditions are described below:

Astigmatism Vs. Myopia Vs. Hyperopia

What are the Complications of Astigmatism?

Astigmatism, if left uncorrected, can lead to several complications, such as:

• Amblyopia (Lazy Eye): Most common in children, amblyopia is caused by the brain suppressing input from the weaker eye when astigmatism is unequal.

• Eye Misalignment (Strabismus or Squint): Uncorrected astigmatism may contribute to eye misalignment, as each eye competes independently to compensate for impaired vision.

• Chronic Headaches: Repetitive tension headaches, often confused with migraine or stress, can be caused by chronic overuse of the eye muscles.

• Declining QOL: Quality of life (QOL) decline includes lower night vision and reduced visual acuity when reading, working with screens, and seeing faces from a distance.

• Keratoconus Progression: Irregular astigmatism in a patient with diagnosed keratoconus may indicate an early stage, potentially leading to a very thin cornea that requires surgical correction.

Astigmatism During Pregnancy

Pregnancy can sometimes cause temporary changes in your vision, including changes in astigmatism. Hormonal fluctuations during pregnancy can increase fluid retention, which may slightly change the thickness and curvature of the cornea. Since the cornea helps focus light into the eye, even small changes in its shape can affect how clearly you see.

You may notice blurred or distorted vision, eye strain or difficulty focusing. These changes are usually temporary and may improve after pregnancy as hormone levels and fluid balance return to normal. However, sudden or significant changes in vision should not be ignored, as they can sometimes be linked to other pregnancy-related conditions that require medical attention.

When Should I See My Healthcare Provider?

If you experience any of the following symptoms, you should see an eye specialist (ophthalmologist or optometrist) for astigmatism:

• Blurred or distorted vision, which worsens with blinking.

• Headaches are a chronic problem, particularly when reading or using the screen.

• Your child squints often, sits very close to the TV, or has trouble at school.

• Halos or glares around lights, especially at night.

• Have eye strain or fatigue following normal daily activities.

• An eye exam was not performed in the last year, and you are older than 40 years.

• Your current glasses do not seem to give you good vision anymore.

• Having diabetes, or a family history of keratoconus and other corneal diseases.

How is Astigmatism Diagnosed?

An eye doctor usually diagnoses astigmatism during a comprehensive eye examination. The doctor assesses your vision and checks for any refractive errors that may be affecting how clearly you see. In many cases, these examinations are enough to identify astigmatism and determine the appropriate vision correction.

If the doctor needs a more detailed assessment, additional tests may be performed to examine the shape and curvature of the cornea. The following tests can also help identify irregular astigmatism that may affect vision:

Diagnostic Overview Table

How is Astigmatism Treated and Managed?

The treatment and correction processes of astigmatism include:

Common Medicines Used to Treat Astigmatism

There are no common medicines that directly treat astigmatism. Management usually involves corrective glasses, toric contact lenses, or refractive surgery to improve how light focuses on the retina. Doctors might prescribe secondary medication such as lubricating eye drops. Eye drops may also be prescribed for related problems, such as dry eyes, allergies, infections, or after eye surgery, but they do not correct astigmatism itself.

Living with Astigmatism: Challenges and Patient Care

Living with astigmatism can affect vision comfort, reading, screen use, night driving, and day-to-day productivity. Most cases are manageable with glasses, contact lenses, or surgery when suitable.

The following are some of the challenges and patient care points for astigmatism patients:

What is the Prognosis for Astigmatism?

People eligible for refractive surgery, such as LASIK, can get a permanent correction for astigmatism.

Early correction of refractive errors can prevent amblyopia and promote visual development in children. For the vast majority of patients, astigmatism can be managed with proper diagnosis and consistent correction.

How to Prevent Astigmatism?

To avoid developing astigmatism, the following measures can be helpful:

• Children and adults over 40 years of age should have an eye examination at least once a year.

• Wear safety glasses when playing sports or working in an industrial setup.

• Avoid constantly rubbing your eyes, as it can scratch the cornea.

• Maintain diabetes and blood pressure to prevent changes in the lens that affect the whole system.

• Always work or read in proper lighting to prevent compensatory eye strain.

• Ensure follow-up after eye surgery; post-surgical astigmatism can be corrected if it is identified early.

• Promote outdoor activity in children for better coordination and eye development.

Astigmatism can also be genetic, so it may not always be possible to prevent it. If astigmatism or other vision problems run in your family, regular eye examinations can help detect changes early and ensure timely correction.

Astigmatism Treatment Cost in India

The cost of astigmatism treatment varies depending on the severity of the refractive problem, the type of vision correction chosen, the hospital or eye facility, and the city in which treatment is received. Many people will find that spectacles and contact lenses are sufficient, but some may choose to have refractive surgery for long-term vision correction.

The table below outlines the astigmatism treatment cost in India:

Note:These are approximate costs and may vary depending on the hospital or eye centre, city, surgeon's expertise, technology used, and the individual's eye condition. Consult an ophthalmologist for an accurate treatment plan and a personalised cost estimate.

Does Health Insurance Cover Astigmatism?

Health insurance may cover surgical correction of astigmatism under specific conditions. LASIK may be covered when the refractive error is 7.5 dioptres or above, provided the procedure is medically necessary. Coverage may also apply in cases of injury-induced refractive error, refractive changes following previous surgery, or physical inability to wear glasses or contact lenses. A waiting period may apply before you can claim the treatment.

However, regular vision correction for astigmatism, such as glasses or toric contact lenses, is generally not covered under standard health insurance policies in India because it is considered a personal care expense.

Before undergoing any surgery, check with your insurance provider to confirm your eligibility, applicable waiting period and any sub-limits under your policy.

How Much Health Insurance Coverage is Needed for Astigmatism?

Out-of-pocket expenses for most people with astigmatism who wear spectacles or contacts are not that high.

However, you might need higher insurance coverage when surgical correction is prescribed by the doctor. An insurance coverage of around ₹5 to ₹10 lakh should suffice for astigmatism treatment expenses, including surgery costs and hospital stays.

Several insurers may not include LASIK in their general coverage plans, as they categorise it as a cosmetic surgery. It is suggested to check with the insurer about the plan you have or want and what they cover. Read the policy details carefully to understand the exclusions and inclusions.