Everything you need to know about diagnosing and treating astigmatism

Medical

Have you or a child been diagnosed with astigmatism? Find out what it is and what treatments are available.

Astigmatism is a common refractive error, occurring in about one in three people. It is often present at birth, but it can also develop over time. It occurs most frequently with myopia (nearsightedness) or hyperopia (farsightedness). The rate of astigmatism increases dramatically from 14.3% in 15-year-olds, to 67.2% in the over 65s.

What causes astigmatism?

The exact cause of astigmatism isn’t always clear. Many people are born with it, while others develop it during childhood or young adulthood. It is essentially a refractive error – a problem with how your eye focuses light.

In a perfectly shaped eye, the cornea (the clear front layer) and the lens (an inner part that helps focus) are both smooth and curved equally in all directions, like a ball. This allows light to be focused sharply onto the retina, resulting in clear vision.

However, if you have astigmatism, either your cornea or lens is shaped more like a rugby ball or an egg. This irregular shape causes light to be refracted (bent) at two different angles, resulting in a variety of symptoms, including:

  • Blurry or distorted vision at all distances
  • Headaches
  • Eye strain
  • Squinting
  • Difficulty seeing clearly at night
  • Needing glasses for both near and distant vision

How is astigmatism diagnosed?

If you’re experiencing any of these symptoms, it’s essential to have a comprehensive eye examination. Even if your symptoms are not caused by astigmatism, they could be the result of another ocular issue that could be resolved with glasses or contact lenses.

To diagnose astigmatism, an eye care professional will use a simple, non-invasive test called a dilated eye exam, which allows them to thoroughly assess your eye health and vision.

Three ways astigmatism can be treated

The good news is that astigmatism is highly treatable. There are three main approaches to correcting astigmatism: glasses, contact lenses, and surgery. 

1) Glasses for astigmatism

For many people with astigmatism, especially those with mild to moderate cases, glasses are the first line of treatment. The lenses in these glasses are specially designed to counteract the irregular shape of your cornea or lens, allowing light to focus correctly on your retina. This correction reduces blurriness and distortion, alleviating symptoms like headaches and eye strain.

Glasses are particularly suitable for children, whose eyes are still developing.

2) Contact lenses for astigmatism

Much like glasses, contact lenses can also effectively correct astigmatism. There are several types of contact lenses available for people with astigmatism:

  • Toric soft contact lenses: These lenses have different powers in different meridians of the lens to correct the astigmatism.
  • Gas permeable contact lenses: These rigid lenses maintain their shape on the eye, which can help correct astigmatism.
  • Hybrid contact lenses: These combine a rigid centre with a soft outer ring, providing the clarity of a gas permeable lens with the comfort of a soft lens.

3) Surgical options for astigmatism

For those seeking a more permanent solution, or for whom glasses and contacts aren’t suitable, several surgical options are available to correct astigmatism:

Laser eye surgery

Refractive surgery uses a laser to reshape the cornea, correcting the refractive error. There are several types of laser eye surgery that can treat astigmatism:

  • LASIK (Laser-Assisted In Situ Keratomileusis): This popular procedure involves creating a thin flap in the cornea, using a laser to reshape the underlying corneal tissue, and then repositioning the flap.
  • LASEK (Laser-Assisted Subepithelial Keratectomy): Instead of creating a flap, the surgeon loosens the cornea’s thin protective cover (epithelium) with a special alcohol, reshapes the cornea with a laser, and then repositions the epithelium.
  • PRK (Photorefractive Keratectomy): Similar to LASEK, but the epithelium is removed entirely and allowed to grow back naturally, conforming to the cornea’s new shape.
  • Epi-LASIK: This procedure uses a special mechanised blunt blade to separate a very thin sheet of epithelium before reshaping the cornea with a laser.
  • SMILE (Small-Incision Lenticule Extraction): This newer technique reshapes the cornea by creating a small lens-shaped bit of tissue (lenticule) below the cornea’s surface, which is then removed through a tiny incision.

Astigmatic Aeratotomy (AK)

This procedure involves making microscopic incisions in the steeper meridian of the cornea. These incisions cause the cornea to assume a more spherical shape, reducing the degree of astigmatism.

Cataract surgery with astigmatism correction

For patients with both cataracts and astigmatism, there are options to address both issues during cataract surgery.

Opposite Clear Corneal Incisions (OCCI)

In addition to the incision made to treat the cataract, another incision is made on the opposite side to simultaneously correct astigmatism.

Toric Intraocular Lenses (IOLs)

These specially designed lenses can be implanted during cataract surgery to correct astigmatism. For private patients, advanced options like Extended Depth of Focus (EDOF) lenses are available, which can correct both near and distance vision, while the NHS only offers standard lenses.

Private treatment may be available through your private healthcare insurance but the EDOF lens often comes at an additional cost.

What to expect from astigmatism surgery

If you’re considering surgical correction for your astigmatism, here’s what you can expect.

Referral and consultation

You’ll typically be referred by an optician or GP. During your consultation, your eye surgeon will assess your suitability for different surgical options based on the severity of your astigmatism, age, overall health, and other factors.

Preparation

Your surgeon will review your medical history, including any medications you’re taking. Some medications can affect pupil dilation or increase the risk of bleeding, so it’s crucial to provide a complete drug history.

The procedure

On the day of surgery, your surgeon will explain the process step-by-step to ease any anxiety. The eye will be cleaned and held open with a small clip. You’ll be asked to look at a bright light, and numbing drops will be applied.

While you may still have some sensation, you shouldn’t feel pain. The procedure itself is typically quite quick, often taking only six to eight minutes.

Recovery

Most patients start to see improvements in their vision within the first week, with significant improvements typically occurring after about two weeks.

Follow-up

You’ll need to see your optician 4-5 weeks after the procedure to check the outcome. At Midland Eye, we offer additional surgery for extreme astigmatism if needed.

Post-surgery expectations and tips

After surgery, many patients find they no longer need to wear thick glasses all the time. While you may still need reading glasses (especially with standard NHS lenses), your overall vision should be significantly improved. Private patients who opt for EDOF lenses may not need glasses at all.

It’s important to note that some procedures, like AK or OCCI, can initially cause a gritty, dry feeling in the eye. Using artificial teardrops can help alleviate this discomfort.

The benefits of astigmatism correction surgery typically last a lifetime, with most patients not requiring further surgeries. However, it’s still important to have regular eye check-ups to monitor your overall eye health.

Ramesh Sivaraj is an Ocular Consultant at Midland Eye, which was founded by four ophthalmic surgeons who wanted to provide patients with a comprehensive, specialist service for the diagnosis and treatment of all eye conditions.

The Midland Eye team are leaders in their field and offer a consultant-only service to all patients requiring eye care or surgery. Every consultant is qualified to treat common eye conditions such as cataracts but each one also has a particular area of specialisation, ensuring that patients get the best possible outcome, no matter what the diagnosis.