Positive Health Online

Options For Treating Astigmatism

by Ramesh Sivaraj MBBS MS DNB PG Cert Medical Science FRCS Ed FRCOphth

Astigmatism is a common eye condition that affects millions of people worldwide. If you have ever experienced blurry or distorted vision, headaches, or eye strain, you might be dealing with astigmatism.

Astigmatism is essentially a refractive error ─ a problem with how the 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.

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However, if someone has astigmatism, either the 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.

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Causes and Symptoms of Astigmatism

The exact cause of astigmatism is not 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 is 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.

The symptoms of astigmatism can vary, but common signs include:

1. Blurry or distorted vision at all distances;
2. Headaches;
3. Eye strain;
4. Squinting;
5. Difficulty seeing clearly at night;
6. Needing glasses for both near and distant vision.

Anyone experiencing any of these symptoms should have a comprehensive eye examination. Even if the 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 eye health and vision.

A dilated eye exam is a thorough examination of the retina and other internal structures of the eye, where eye drops are used to dilate (widen) the pupils. Dilating the pupils allows a much clearer and wider view of the back of the eye, allowing for a more detailed inspection.

The effects of the dilation drops can last for a few hours, causing sensitivity to light and blurred vision, especially with close-up tasks. It is often recommended to bring sunglasses to reduce discomfort, and patients are strongly advised to avoid driving immediately after the exam.

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

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Glasses

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 the cornea or lens, allowing light to focus correctly on the retina. This correction reduces blurriness and distortion, alleviating symptoms like headaches and eye strain.

Glasses are a quick, safe, and non-invasive option that can provide immediate improvement in vision. They are particularly suitable for children, whose eyes are still developing, and for adults with milder astigmatism who prefer a simple solution.

Contact Lenses

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.

Contact lenses can be an excellent option for those who do not want to wear glasses or need vision correction during sports or other activities where glasses might be impractical.

Surgical Options

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 Keratotomy (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 private healthcare insurance but the EDOF lens often comes at an additional cost.

Surgical Process: What to Expect

For anyone considering surgical correction for astigmatism, here's what to expect:

1. Referral and Consultation: Patients are typically referred by an optician or GP. During the consultation, the eye surgeon will assess the patient’s suitability for different surgical options based on the severity of the astigmatism, age, overall health, and other factors.
2. Preparation: The surgeon will review the patient’s medical history, including any medications they are taking. Some medications can affect pupil dilation or increase the risk of bleeding, so it is crucial to provide a complete drug history.
3. The Procedure: On the day of surgery, the surgeon will explain the process step-by-step to ease any anxiety. The eye will be cleaned and held open with a small clip. The patient will be asked to look at a bright light, and numbing drops will be applied. While the patient may still have some sensation, they shouldn't feel pain. The procedure itself is typically quite quick, often taking only 6-8 minutes.
4. Recovery: Most patients start to see improvements in their vision within the first week, with significant improvements typically occurring after about two weeks.
5. Follow-up: Patients need to see their 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 they may still need reading glasses (especially with standard NHS lenses), overall vision should be significantly improved. Private patients who opt for EDOF lenses may not need glasses at all.

It is 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 is still important to have regular eye check-ups to monitor overall eye health.

Summary

Astigmatism is a common condition which can be congenital (present at birth) or it can develop over time. Symptoms may vary in intensity depending on the degree of astigmatism. Mild astigmatism may go unnoticed, while moderate to severe cases typically impact daily activities and visual comfort.

However, astigmatism does not have to impact quality of life. A range of treatment options are available: prescription lenses with specific curvatures can correct astigmatism by compensating for the irregular shape of the cornea or lens; Toric contact lenses, designed specifically for astigmatism, can help focus light evenly, and rigid gas-permeable lenses or hybrid contact lenses (a rigid centre with a soft outer ring) are also effective for some people with astigmatism; procedures like LASIK, LASEK or PRK reshape the cornea to correct astigmatism – although it should be noted that not everyone is a candidate for surgery. And the various treatments mean that clear, comfortable vision is achievable for most people with astigmatism.

Remember that regular eye examinations, with an eye specialist, are key to maintaining good eye health and catching any vision problems early.