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LASIK: What you should know about the vision correction surgery

Those who suffer from visual impairment normally make use of spectacles or contact lenses in order to correct their vision. However, there’s an increasing number of people who wish to undergo surgery – They try LASIK. Read here what the procedure is all about and what you should be aware of.



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What is LASIK?

The term LASIK stands for laser in-situ keratomileusis. This popular vision correction surgery has been employed since the 1990s. The correction is achieved with a special laser that reshapes the cornea with the purpose of changing the focusing power.1

In nearsightedness (myopia), farsightedness (hyperopia) or astigmatism , the environment usually appears blurred and unfocused. With these forms of ametropia, the refractive power of the eye is not optimal. Objects cannot be sharply imaged on the retina. The LASIK technique changes the refractive power of the cornea in such a way that blurred vision is corrected. Thus, light that’s travelling through the cornea can properly hit the retina located in the back of the eye. Clear vision is possible again without glasses or contact lenses.2

Surgical procedures aimed at improving the focusing power of the eye are called refractive surgery.

How exactly does LASIK eye surgery work?

With good vision, images are focused on the retina in the back of your eye. With visual impairment, the images end up being focused elsewhere, resulting in blurred vision.

Here you see how the light wrongly hits the front of the retina in nearsightedness. Source: Fashion Eye Center

Source: Fashion Eye Center

LASIK lasers come into play for these visual defects. They change the cornea to the extent that the light focuses on the retina as it should when this is healthy. The reshaping of the cornea is achieved by means of a laser. A flap is created in the cornea under which the laser is then focused on the eye.3

The steps of the surgery:4

As with all other eye laser methods, visual acuity should have remained stable for at least one year prior to LASIK surgery. No eye diseases (e.g. cataract or retinal diseases) should be present.

A laser eye operation can last anything from 15 to 30 minutes, depending on the type of surgery involved and the patient’s indi­vidual prescription.

Lasik, step 1

Before your doctor starts using the laser, your eye is anaesthetised with a local anaesthetic so that you don’t feel anything during the actual operation.

Lasik, step 2

Using a plane, the surgeon first cuts off a thin slice of the cornea. The doctor then flips this “flap” to the side like a book cover.

Lasik, step 3

The deeper layers of the cornea are then flattened (for short-sighted patients) or steepened (for far-sighted patients) with the aid of a laser beam. The ultraviolet light beam removes these microscopic amounts of tissue from the cornea so that it focuses the light more precisely on the retina. Shortsightedness and farsightedness are not the only vision problems that can be treated by laser. Excimer lasers can also correct astigmatism by returning an irregular cornea to its normal shape.

Lasik, step 4

After the operation, the flap is folded back again. It will grow back on its own. However, the cornea loses its mechanical resistance. This cannot be changed by modern methods.

The good news: The laser is a very gentle method to improve vision. No bandages or stitches are required.

How long does it take to recover from LASIK?

In most cases of laser eye surgery, your vision returns several hours after the surgery. 

Over time, your eyes will improve steadily. So it is possible to go back to work a few days after the operation and follow your daily routines. What you have to do for a certain period of time, though, is to carefully cleanse your eyes every day and avoid sporting activities.

Many patients complain of dry eyes and foreign body sensations after the operation. In addition, there are glare effects at night, which can influence you to such an extent that they can no longer drive. Disturbing light phenomena, so-called halos, also frequently occur after LASIK operations. These symptoms usually disappear within the first three months. However, when corrections exceed five dioptres, the glare effects and halos can persist.

The symptoms following LASIK:

  • Discomfort during the first few days, such as mild irritation and light sensitivity
  • Halos, glare and starbursts in low-light environments
  • Dry eyes
  • Hazy vision
  • Reduced sharpness of vision

In the vast majority of cases, these problems are temporary and disappear completely within three to six months. 

Is LASIK safe?

We can answer that question with a resounding yes. This is due to the extremely low risk of complications from the operation.6

The results of modern LASIK surgery, measured in terms of visual acuity, refractive results and patient satisfaction, have now been analysed. A team of researchers from refractive surgery centres in the US and Germany have investigated 97 LASIK studies published between 2008 and 2015. Thus, the outcomes of almost 68,000 eye surgeries were evaluated.

And the evaluation is consistently positive.

  • 98.6 percent of eyes were within +/- 1.0 diopter of the target refractive outcome.
  • And most importantly, 98.8 percent of patients reported being satisfied with their LASIK results.7

What are the disadvantages of LASIK eye surgery?

An operation can never be risk-free. The greater the visual defect, the more likely the incidence of side effects. Generally, the laser treatment is used for patients with low, medium and high shortsightedness/ myopia, (see below), with low farsightedness (up to +4 dioptres), and with astigmatism. However, be aware that high myopia is a so-called progressive impairment, i.e. shortsightedness will come back after several years, even after having it succesfully operated with a laser. 

The three forms of shortsightedness (myopia):

  • Myopia simplex (up to –3D)
  • Myopia modica (-3,25 to –6,0D)
  • Myopia gravis (above –6D) = progressive

Besides, there are other limitations, for example if the cornea is very thin and therefore shouldn't be operated. Once the eye has been operated, the cornea is thinned and can't undergo a second surgery.

Thus, surgical solutions can be recommended especially when your eyes don't tolerate contact lenses or you refuse to wear spectacles.

One thing you should keep in mind is that all ophthalmologists wear glasses and don't make use of vision corrections such as LASIK. That's because surgeries always bear certain risks. Besides, they can't be undone.

Having concerns about the safety of the surgery and its consequences on your eyesight is understandable. If you have questions or doubts, it’s best to consult an ophthalmologist who will answer any question you may have about LASIK.

How much does LASIK cost?

The prospect of improved vision and the removal of glasses or contact lenses makes LASIK very attractive for many people. The surgery's not exactly cheap, though. Depending on how severe the visual impairment is, which surgeon you choose, and which technology he or she uses, you must pay between 800 and 1000 euros per eye. Often included in the price is the actual operation, pre and post-surgery care, and a follow-up procedure, if the first LASIK eye surgery requires fine tuning.9

The factors influencing the price:10

  • The degree of vision correction: LASIK eye surgery is usually more expensive for people with extremely poor vision. This means, the worse your vision is, the more expensive your treatment will probably be.
  • The type of laser technology: Another component of LASIK eye surgery costs is the type of technology used. New technologies often cost more than older ones. Before you decide on the technology, be sure to ask for the price of the offered LASIK procedure so that you know exactly what to expect.
  • The doctor’s expertise and the clinic’s repu­tation: The cost of LASIK eye surgery may also be influenced by the surgical skill of the doctor. Experienced surgeons working in renowned practices and clinics tend to charge more since they are bringing a higher level of skill to the procedure.

LASIK vs. PRK: Which eye surgery is better?

Last but not least, you should know about another popular vision correction surgery that is often compared to LASIK. Photorefractive Keratectomy, PRK, was first performed in 1987 and is considered the predecessor of LASIK. Just like LASIK, PRK is a form of refractive surgery to correct myopia, hyperopia and astigmatism. PRK also works by reshaping the cornea with an excimer laser so that the light entering the eye is properly focused on the retina for clear vision. There are a few differences however, that we would like to point out to you.

  • The main difference between PRK and LASIK is the first step of the procedure. PRK is designed to correct vision defects by using an excimer laser to reshape the cornea without creating a flap in it. First, in PRK the thin outer layer of the cornea, the corneal epithelial tissue, is pushed aside or removed mechanically. In contrast to LASIK, which produces a complete corneal flap, PRK leaves a thin layer of corneal epithelium.
LASIK vs. PRK
  • In the next step, the excimer laser ablates the cornea by a certain thickness based on the values measured during the preliminary examination. The refractive power of the cornea is changed in such a way that incoming light rays hit the retina correctly bundled – a sharp visual image is created.
  • Finally, the corneal epithelium is pushed back and covered with a therapeutic contact lens. The contact lens protects the epithelium during the first 3 to 5 days, i.e. until the surface has healed and is subsequently removed. However, it may take two to three months for the vision to stabilize.11

Take a look at the comparison of the features of PRK and LASIK:

PRK LASIK
Costs from 635 £ per eye from 760 £ per eye
Application since 1987 1990
With Corneal Flap No Yes
Duration of Treatment 15 – 30 Min 15 – 30 Min
Healing Time Possibility of pain: 4 days – Recovery time: 8 to 12 weeks Possibility of pain: 1 to 2 days – Recovery Time: 2 weeks
Other Features Ideal for thin, flat or too steep corneas Suitable procedure for a regular cornea

This text was created with the expertise of our optician Jakub Odchazel.

References:

1FDA 2webmd 3Laser Surgery Hub 4Der Spiegel 5Der Spiegel 6American Refractive Surgery Council 7All about vision 8VSP 9VSP 10Augen Lasern Vergleich

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