Refractive Surgery: A Guide

Refractive laser eye surgery, also known as vision correction surgery, refers to the surgical procedure involved in fixing certain vision problems by reshaping the cornea, allowing light to focus properly on the retina.

In this guide, we’re going to look at the different types of surgery available and explain how refractive laser eye surgery works.

What Are the Main Refractive Errors Treated by Laser Eye Surgery?

Laser eye surgery is available as a treatment for a number of refractive errors, including:

• Myopia (Short-sightedness): People with myopia struggle to see things in the distance, with objects often becoming blurry, but their close-up vision remains clear.
• Hyperopia (Long-sightedness): Opposite to myopia, people with hyperopia will often be able to see objects in the distance clearly but will often find that items in the near distance are blurry and fuzzy.
• Astigmatism: Another common eye condition, astigmatism causes distorted or blurred vision. It arises when the lens or cornea is an irregular shape. The majority of glasses wearers will have a certain degree of astigmatism.
• Presbyopia: Occurring naturally during the ageing process, presbyopia is a type of long-sightedness. It’s caused by the lens hardening and losing some of its elasticity, meaning it cannot focus the light on the retina correctly when looking at close-up objects.

Types Of Laser Eye Surgery

LASIK Eye Surgery

LASIK (Laser-Assisted In-Situ Keratomileusis) is one of the most popular laser refractive procedures. During LASIK, a thin flap is created on the front of the cornea using a microkeratome or femtosecond laser. Once the flap is lifted, an excimer laser is utilised to reshape the underlying cornea, correcting refractive errors such as myopia, hyperopia, and astigmatism. After the laser treatment, the flap is repositioned, allowing it to adhere naturally to the cornea without the need for stitches.

Benefits of LASIK:

• Quick Recovery: Most patients notice improved vision within a day.
• Minimal Discomfort: The procedure is typically painless, with many patients reporting only mild discomfort.
• Long-Lasting Results: LASIK provides a permanent correction for many individuals.

LASEK Eye Surgery

LASEK (Laser-Assisted Sub-Epithelial Keratomileusis) is similar to LASIK but involves a different approach to the cornea’s surface. In LASEK, the epithelial cells on the front of the cornea are loosened using a diluted alcohol solution and then moved aside. The excimer laser is then applied to remodel the cornea beneath. After the laser treatment, the epithelial layer is repositioned on the cornea’s surface.

Benefits of LASEK:

• Ideal for Thinner Corneas: LASEK may be a better option for patients with thinner corneas where LASIK is not advisable.
• Less Risk of Flap Complications: Since there is no flap creation, LASEK minimises certain surgical risks associated with LASIK.

Transepithelial PRK Surgery

Transepithelial PRK (Photorefractive Keratectomy) is one of the latest forms of laser eye surgery. It involves the complete removal of the epithelial cell layer of the cornea using a laser, which is also used to alter the corneal shape. This results in less pain than LASEK, along with enhanced precision and a faster recovery of the patient’s eyesight.

Benefits of Transepithelial PRK:

• No Flap Required: This eliminates flap-related complications.
• Faster Recovery: The new technique offers quicker healing compared to other methods.

PTK Surgery

PTK (Phototherapeutic Keratectomy) is a specialised form of laser surgery used to treat corneal surface irregularities, scarring, and recurrent corneal erosions. Like PRK, PTK involves the complete removal of the epithelial layer, utilising the excimer laser to regularise the corneal surface. This procedure is particularly beneficial for patients with corneal scarring or other surface defects.

Benefits of PTK:

• Restores Corneal Surface: PTK helps to improve vision by smoothing out irregularities.
• Effective for Scar Treatment: This technique can address issues that may not respond well to other procedures.

What Are the Benefits of Laser Eye Surgery?

Laser eye surgery comes with a number of benefits, not just the fact that your vision can return to what it was before glasses and/or contact lenses.

More than 95% of patients are satisfied with the results they get from the surgery.

There is also very little pain associated with these types of procedures. For the majority of patients undergoing laser eye surgery, vision returns to normal within a few days of the surgery. Furthermore, the recovery time is quick with no stitches or bandages being required afterwards.

Laser eye surgery procedures can also be repeated to correct your vision further down the line, which some patients may require due to changes in their prescription levels at a later stage of their life.

Finally, in most cases, patients won’t need to wear corrective eyewear, which reduces the potential restrictions they previously faced. However, some individuals may require glasses when engaging in specific activities. For example, older patients often rely on reading glasses.

Am I Suitable for Laser Eye Surgery?

Inclusion Criteria:

You have a refractive error, which tends to be in the following range:
• Up to -10.00 of short-sightedness (myopia)
• Up to +4.00 of long-sightedness (hyperopia)
• Up to +/- 6.00 of astigmatism

You’re generally healthy

You don’t have any allergies to anaesthesia

Criteria for Possible Exclusion

You are under 21; an eye prescription must have been stable for at least two years before undergoing surgery, as eyes continually change until you’re 21.

You’re over the age of 65; due to the increased risk of age-related cataracts and macular degeneration.

You’re suffering from a medical condition such as diabetes, hepatitis C, the herpes virus, rheumatoid arthritis, or lupus.

Your corneas are very thin, or you have glaucoma or cataracts.

You’re taking immunosuppressant drugs.

You’re pregnant or breastfeeding.

You have been diagnosed with dry eyes.

You have a job that’s dependent on your eyesight (although not an exclusion per se; professional athletes, pilots, and others are advised to consider the implications if the procedure does go wrong).

What Are the Possible Risks of Laser Eye Surgery?

As with all forms of surgery, there are problems that can arise during or after the operation.

Dry Eyes

Your tear production is temporarily decreased after LASIK. This is why your eyes may feel drier for up to 6 months after your operation. This can then reduce your vision quality. However, to assist you in this period, your eye surgeon may offer you some eye drops.

Double Vision, Halos, and Glare

At night, you might notice yourself experiencing double vision, halos, and glare. However, these tend to last a few days, or at the most, a few weeks.

Under or Over Corrections

If there isn’t enough tissue removed from your eye, you might not achieve the vision you set out for. This problem is more common in those who are short-sighted and may require a repeat procedure to remove more tissue.

Alternatively, it’s possible to remove too much tissue during the procedure. This is more difficult to correct than undercorrections.

Astigmatism

Arising from uneven tissue removal, this may result in the need for contact lenses, glasses, or further surgery.

Flap Problems

Complications can arise due to the flap that’s removed or folded back during the surgery. This can cause excess tears or infection, and the epithelium may grow back abnormally.