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Laser Eye Surgery Side Effects – Are There Any And What Are They?

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The idea of undergoing surgery on your eyes (or any kind of surgery, for that matter) sounds daunting. However, laser eye surgery procedures not only have excellent success rates, they also have an excellent patient safety record.

The chances of developing severe complications, such as reduction in vision, are extremely rare and while minor side effects can develop, they’re easily resolved via a follow-up treatment or medication.

It’s worth knowing that infection and reduction in vision, e.g. from a corneal scar, is significantly more likely to happen due to contact lenses than from laser eye surgery.

Here’s what could happen and how they can be managed.

Dry Eyes

Laser eye surgery procedures, like LASIK and LASEK, typically cause a temporary decrease in tear production. This is because the procedure causes some nerves in the cornea to be cut which reduces corneal sensitivity and as a result, your eye doesn’t think it needs to lubricate as much. And hence, you produce fewer tears.

The corneal nerves regrow and measurements of tear production and lubrication of the eyes are back to normal preoperative levels by six months after treatment.

Although this is temporary (for approximately the first six months or so after your surgery), dry eyes can cause both discomfort and reduce the quality of your vision. You can make this condition more manageable with lubricating eye drops, which your doctor can prescribe or can also be purchased over the counter at any pharmacy.

Want To Find Out If You’re Suitable?

If you’re wondering whether laser eye treatment is the right choice for you, there are some key things to consider…

Glare, Halos and Double Vision

Most patients usually experience some glare or halos after laser eye surgery during the first month or so. This is when you see a ring of hazy illumination around light sources, like car headlights, and it can affect your vision. Especially night vision.

But don’t panic – this is completely temporary and normal. Any laser eye surgery patient can experience this side effect, regardless of their age, eye condition and treatment method.

Glares and halos happen because light gets scattered within the cornea during the initial healing phase. As you heal, the side effect will disappear.

Manage glares and halos by keeping other lights on to prevent your pupils from fully dilating. Your doctor may also prescribe you eye drops to constrict your pupils and give you clearer vision.

Long-term halos and glare are fortunately now much rarer than with early lasers used in the past. The risk of ongoing problems is linked to the size of the prescription as it’s more possible with very high corrections.

Studies found that pupil size at night did not correlate with the likelihood of getting night vision issue, but size of the prescription did.

Overcorrection or Undercorrection

In rare cases, your vision may be overcorrected or undercorrected.The main variable is the individual healing response of the patient’s cornea.

We estimate the likelihood of being glasses-free after the initial treatment at 99.8 percent.

The excimer laser used to correct vision is extremely accurate, with an accuracy down to less than one-fiftieth of a dioptre. However, the healing response accounts for the variation in outcomes and so sometimes an enhancement procedure may be needed.

Being undercorrected or overcorrected after laser eye surgery may lead to you not getting the results you were hoping for and you might still have to wear glasses or contact lenses. Usually, this is a temporary affair until the cornea has completed its healing response.

In these cases, it’s possible to have a follow-up procedure to correct your vision. This depends on your eye condition so it’s best to consult your surgeon for more advice.

Problems Associated with the Corneal Flap

Laser eye surgery involves making a precise layer of separation in the cornea using an instrument called a femtosecond laser and creating a flap. Another laser will then be used to reshapef the corneal tissue underneath. Once the tissue has been corrected, the flap will be put back into place.

“It’s important to realise that these side effects are very rare, occurring in less than half a percent of laser eye surgery procedures.”

If the flap wasn’t made properly or you don’t follow best practices recommended by your clinician following the surgery (such as avoiding getting water in or frequently rubbing your eyes), flap issues can occur. This can affect the way the corneal flap heals.

This can lead to:

  • Epithelial ingrowth – the outermost corneal tissue layer (called the epithelium) may grow abnormally under the flap and cause discomfort or blurred vision. Additional surgery can lift the flap and remove these cells. While this complication is common with blade-cut techniques, the advent of modern femtosecond laser LASIK has reduced the incidence of epithelial ingrowth to zero percent with the primary procedure. If a re-treatment is needed (in one to four percent of cases), mild ingrowth can be seen, and treated.
  • Irregular astigmatism – if the cornea didn’t heal properly, an irregular, curved corneal surface may form (astigmatism). This can cause symptoms such as double vision or “ghost images”. Retreatment or enhancement surgery can fix this.
  • Excessive inflammation under the flap (diffuse lamellar keratitis or DLK) – some inflammation is normal but if uncontrolled, it can affect healing and lead to vision loss. Topical steroids will clear the inflammation in most cases. The flap may also need to be lifted and cleaned.
  • Bulging of the eye surface (keratectasia) – if too much corneal tissue is removed or the cornea is weak, uncommon bulging of the eye’s surface can occur. This is extremely rare but special contact lenses may be prescribed to hold the cornea in place. Or, a treatment called corneal collagen crosslinking might be needed to strengthen the cornea.
  • Eye infections – if you experience eye redness, oozing or pain, your eyes may have developed an infection. This can easily be cleared up with eye drops or oral medications prescribed by your doctor. The risk of infection with modern LASIK is around one in 20,000 cases.

Factors that Increase the Risk of Side Effects

There are certain conditions that can increase the risks associated with laser eye surgery. If you have these conditions, your doctor may advise you to not have the procedure. These include:

  • Autoimmune disorders e.g. rheumatoid arthritis.
  • Weakened immune system due to immunosuppressive medications.
  • Persistently dry eyes.
  • Unstable vision due to age, medications, hormonal changes, pregnancy or if you’re breastfeeding.
  • If you have any conditions that may affect the eye e.g. keratitis, herpes simplex, cataracts or glaucoma.

So, is Laser Eye Surgery Worth it?

These complications sound scary, we know. But it’s important to realise that they’re very rare, occurring in less than half a percent of laser eye surgery cases. They’re also amenable to procedures to correct the problem should they occur.

The advent of new technologies has revolutionised the landscape of complications of the laser eye surgery. For example, ectasia is now treatable with collagen cross linking and epithelial ingrowth has been eliminated as a complication of primary LASIK procedures.

In addition, LASIK eye surgery is not only the most common form of laser eye surgery. It’s also the safest and most effective.

The benefits of laser eye surgery outweigh the (very rare) chances of complications by far. The risks of eye damage from contact lenses are three times higher than that of laser eye surgery.

“The risks of eye damage from contact lenses are three times higher than that of laser eye surgery”

Just think: You could be waking up every morning with crystal clear 20/20 vision instead of blurriness and having to scramble around for your glasses. You don’t have to experience dry, tired eyes from wearing contacts all day, or wear glasses and have them constantly leave rings on your face or slip down because you’re sweaty.

If you’re one of the unfortunate people who has multiple pairs of glasses, such as one for reading and another for looking afar, laser eye surgery frees you from them. Gone are the days of swapping between different pairs of specs and panicking when you realise you’ve left a pair at home.

Find Out More About Laser Eye Surgery

If you’re interested in learning more about laser eye surgery, don’t hesitate to drop us a message. Focus Clinic are the only laser eye surgery clinic in the UK with a published 100 percent success rate.

We’re also the most trusted clinic in the country, as indicated by our reviews.

Our two surgeons have over 45 years of experience and have performed over 35,000 procedures between them.

We also offer a comprehensive aftercare package with a unique 10-year guarantee instead of the usual one year you’d find in other clinics.

To help you make sure that laser eye surgery is right for you, we’ve put together a helpful information pack. You can access it below by pressing the button then entering your email address.

About the Author

Mr David Allamby is the founder and medical director of Focus Clinic - the leading provider of laser eye surgery in London. Focus’ commitment is to be the #1 clinic for vision outcome results with 100% of patients achieving 20/20 vision or even better. He is one of a limited number of UK surgeons who work in laser refractive surgery full-time.


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