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 focus 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 blurry or distorted vision.

Causes and symptoms of 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. In some cases, it can occur after eye surgery or injury.

There’s also a condition called keratoconus, a progressive eye disease where the cornea thins and bulges into a cone-like shape, which can cause severe astigmatism.

Common signs of astigmatism include:

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

If you’re experiencing any of these symptoms, it’s essential to have a comprehensive eye examination. Even if your symptoms aren’t due to astigmatism, they may stem from another ocular issue that could be resolved with glasses or contact lenses.

An eye care professional can diagnose astigmatism through a simple, non-invasive dilated eye exam, which allows a thorough assessment of your eye health and vision.

The good news is that astigmatism is highly treatable, with three main correction options: glasses, contact lenses, and surgery.

Glasses

For many with mild to moderate astigmatism, glasses are often the first line of treatment. The lenses in these glasses are 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 a quick, safe, and non-invasive solution that can provide immediate vision improvement. They’re especially suitable for children and for adults with milder astigmatism who prefer a simple option.

Contact lenses

Like glasses, contact lenses can also correct astigmatism effectively. Options for astigmatic contact lenses include:

• Toric soft contact lenses. These lenses have varying powers across different meridians to correct astigmatism.
• Gas permeable contact lenses. These rigid lenses hold their shape, aiding in astigmatism correction.
• Hybrid contact lenses. Combining a rigid centre with a soft outer ring, these lenses offer clarity with added comfort.

Contact lenses are a good choice for those who want an alternative to glasses or need correction during sports or activities where glasses may be impractical.

Surgical options

For those seeking a more permanent solution, or when glasses and contacts aren’t suitable, several surgical options are available:

Laser eye surgery

Refractive surgery uses a laser to reshape the cornea, correcting the refractive error. Types of laser eye surgery that can treat astigmatism include:

• LASIK. A popular procedure where a thin flap is created in the cornea, reshaped with a laser, then repositioned.
• LASEK. The surgeon loosens the cornea’s thin protective layer, reshapes it with a laser, and repositions the layer.
• PRK. Similar to LASEK, but the protective layer is removed entirely and allowed to regrow naturally.
• Epi-LASIK. A mechanised blade separates a very thin layer of the cornea, which is then reshaped with a laser.
• SMILE. A newer technique that removes a small, lens-shaped piece of tissue through a tiny incision.

Astigmatic keratotomy (AK)

AK involves making small incisions in the steeper part of the cornea to give it a more spherical shape, reducing astigmatism.

Cataract surgery with astigmatism correction

For those with cataracts and astigmatism, it’s possible to address both issues during cataract surgery:

• Opposite clear corneal incisions (OCCI). An extra incision corrects astigmatism along with cataract treatment.
• Toric intraocular lenses (IOLs). These lenses, implanted during cataract surgery, correct astigmatism. Advanced options, like extended depth of focus (EDOF) lenses, correct both near and distance vision and are available privately.

Surgical process: What to expect

For those considering surgery for astigmatism, here’s an overview of the process:

1. Referral and consultation. Typically, you’ll be referred by an optician or GP, after which your eye surgeon will assess your suitability based on your specific needs.
2. Preparation. Your surgeon will review your medical history and medications. Some medications can affect pupil dilation or bleeding risk, so it’s important to be thorough.
3. Procedure. On the day, your eye will be cleaned, numbing drops will be applied, and you’ll be guided step-by-step. The surgery is generally quick, lasting 6–8 minutes.
4. Recovery. Vision improvements usually appear within the first week, with significant gains after two weeks.
5. Follow-up. A follow-up visit to your optician occurs 4–5 weeks after the procedure. Midland Eye offers additional surgery for extreme cases if needed.

Post-surgery expectations and tips

After surgery, many find they no longer need to wear thick glasses constantly. While some may still need reading glasses, private patients who choose EDOF lenses may not require glasses at all.

Some procedures, like AK or OCCI, may cause an initial gritty, dry feeling. Artificial teardrops can help relieve this. The benefits of astigmatism correction surgery typically last a lifetime, though regular eye check-ups remain important.

Ramesh Sivaraj is an ocular consultant at Midland Eye. You can connect with Midland Eye on Facebook, Instagram, and LinkedIn.