Refractive surgery

Dr. De Wilde was the first in Belgium to use the unique Catalys laser system. This technique can be used for patients who wish to be treated for cataract or for those wishing a refractive replacement of the lens in order to enjoy life freely, without glasses.
Catalys laser system for clear lens replacement and cataract treatment.
The “Catalys precision laser system” allows us to accomplish laser-controlled surgery of the lens. Up to now, all surgical interventions were a manual matter causing sometimes complications such as : a gash in the casing, corneal edema, wrong centering of the artificial lens, residuum astigmatism …
These complications are reduced to a strict minimum due to the use of a very accurate (to within 1 micrometer) infrared laser system and 3D imaging. This new technology allows us to treat eyes in an utmost efficient way compared to the former surgical interventions. As less energy is being put into the eye, the recovery is faster. In the treatment of presbyopia ( old age farsightedness ), the Premium lens ( multifocal artificial lens ) will perfectly, and on a long term, remain centered in the eye through the use of the Catalyslaser. In that way, your eyes will forever keep up with a good vision, from afar as well as from close, after the laser treatment.

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Refractive surgery

This encompasses the treatment of all refractive disorders such as short-sightedness, long-sightedness and astigmatism with the use of an excimer laser. These procedures are performed on an outpatient basis at the Belgian Ocular Laser Centre (BOLC) in Drongen or at the Dr Binkhorst Eye Center (BEC) in Oostburg (NL). The procedure is completely painless and both eyes are always treated during one and the same session. Since the latter end of 2007, we have also been performing “all-laser surgery” or “bladeless surgery” at the BOLC. This means that in LASIK procedures, we now use a femtosecond laser to create the corneal flap, dispensing with the need for blades.

Often, patients visiting our eye clinic ask us: “will I be able to get rid of my contact lenses or glasses?”

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As there are a number of possible treatments, your ophthalmologist will only decide which treatment is most suited to your refractive disorder once you have undergone a comprehensive eye test. Shown below is a picture of the MEL-80 excimer laser we use in Drongen, which is made by the company Zeiss.

MEL 80

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Anatomy and function of the eye structures

All procedures are performed on the cornea or on the eye lens. The cornea is a thin transparent layer, measuring about half a millimetre in thickness which covers the front of the eye. It is located in front of the pupil and the iris. The eye lens is located behind the pupil and has a biconvex shape (i.e. a spherical shape) so that it can refract incoming light onto the retina at the back of the eye. Any information received by the macula of the retina is then transmitted to the brain via the optic nerve in the form of electric impulses.

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Types of refractive disorders

Myopia or short-sightedness: the eye is too long so that the light that hits the cornea and is refracted by the cornea and the eye lens ends up in front of the retina instead of on the macula. These patients do not have great long-distance vision but are able to read without the help of glasses or contact lenses. The laser treatment aims to level the cornea so that the light rays are once again projected onto the retina.

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Hypermetropia or long-sightedness: the eye is too short so that the light rays end up being projected behind the retina. Both the patient’s long-distance and short-distance vision are affected. The laser treatment will restore the convex shape of the cornea so that any incoming light rays are once again sharply projected onto the retina.

Astigmatism or spherical aberration: the horizontal and vertical axes of the cornea have a different curvature. In other words, the cornea is shaped like a rugby ball instead of a soccer ball. Patients suffering from this disorder perceive lines to be curved. To remedy this, the laser will correct one axis more than the other axis so that the patient can see sharply again. This disorder is quite common in combination with the aberrations described above. The laser will treat all the different aberrations in one go. On this picture you can see that the vertical corneal axis is more curved than the horizontal one.

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Your ophthalmologist will choose the most appropriate treatment for your particular problem. This schedule simply shows you which options are available.

Why opt for refractive surgery?

If your are wearing contact lenses you may be showing signs of contact lens fatigue so that you find it increasingly harder to tolerate your lenses for any length of time. The cause of this can be established when counting the endothelial cells with a specular microscope. Soft contact lenses are like a plastic film on top of the cornea which, day in day out, stem the flow of oxygen causing the endothelial cells to die off. Once the cell count drops to below 1200 cells/mm2 (cf. specular microscope) you end up with a condition called corneal oedema as a result of which you see halos and find it harder to see clearly at night-time. Below, you will find a picture of the endothelial cells.

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Lasik

LASIK is a laser technique by means of which dioptres (from -9 up to +3.5D) can be corrected. It allows us to create a very thin corneal flap, which is a completely painless procedure. The laser procedure itself only takes a few seconds and both eyes can be treated during one and the same session. The following day, you will be able to resume all your activities and see quite clearly again. If you are over 45 years of age you will probably still need to use reading glasses after this procedure unless you decided to opt for monovision.

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Watch the video

Below we show you a picture of the LASIK flap straight after the laser treatment; as you can see there is no sign of scarring whatsoever.

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LASIK was pioneered by Dr Pallikaris from Greece in 1989, so this technique has stood the test of time for well over 20 years now. It is a very safe procedure with a tremendous success rate. We use it in 90% of cases.

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Dr Pallikaris and Dr De Wilde at a meeting in Spain (2004)

The most common side effect is that an additional correction may be required because the first laser-therapy session might not have produced the optimum result. This second treatment will be performed two months after the initial one and is required by 5% of patients. Chances of an infection are minimal (1/3000) because the laser-treated area is protected by a little flap. Following this procedure, you will need to apply antibiotic drops to ward off any infections. If you were to contract an infection anyhow, your eye will become red and your sight will deteriorate. In that case, you must contact the clinic without delay so that we can start a specific treatment.
Following the procedure, the flap could also become inflamed. This happens to 1 in 400 patients and is treated with cortisone drops. Sometimes we may rinse underneath the flap to remove any tiny fluff particles.
Creating the flap may also give rise to some complications. For instance, the flap may not be perfectly centred or, the flap may be incomplete as a result of a technical problem with the keratome which produces the flap. In that case, we will have to wait about six weeks before the procedure can be started over again. Below, you can see a picture of the keratome used to make the corneal flap.

Femtosecond laser: now we can also create a corneal flap with laser equipment. It also allows us to select the thickness and centring.

Carl Zeiss Visumax
Carl Zeiss Visumax

Patients may also be troubled by halos or bothered by a red ring around light sources. This side effect normally disappears after a few months. Here we show you a picture of a halo around a light source.

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“Glare”, as shown in the above picture, is another possible side effect of laser therapy but this also disappears after a few months.

Epithelial ingrowth

This problem mainly arises following an additional correction. It is caused by little cells which start growing under the flap and which must be rinsed away afterwards.

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Corneaectasia

A complication which can arise much later is corneal ectasia, which is caused by a little bubble growing on the cornea from within, causing vision to deteriorate. This condition is extremely rare and mainly ensues from the laser having penetrated the cornea too deeply. It can initially be remedied by wearing a semi-hard contact lens and in secondly we can opt for a corneal cross linking (CXL).
This method is used to strengthen the corneal collagen. The procedure is mainly indicated in patients suffering from evolutive keratoconus, but also from pellucid marginal degeneration, corneal ectasia and in patients who have undergone photorefractive keratectomy (PRK). First of all, a dye (riboflavin) is applied to the cornea. The cornea is subsequently exposed to UV LED light for 30 minutes to activate the dye. As a result of this procedure, the rigidity of the cornea increases by 300%.
The frequency of complications mainly depends on the surgeon’s experience. In Drongen, we have been performing LASIK treatments since 1997 and have extensive experience with this technique. Dr De Wilde has personally and successfully performed well over 5000 LASIK procedures.
LASIK can also be used in patients who still need to wear glasses following a corneal transplant or if, following corneal abrasion or PRK, the desired result has not been attained or also when the refractive difference between both eyes, following cataract surgery, remains too great.

CUSTOM LASIK

This is a laser technique in which special software is used. If your cornea happens to be very thin, or if your pupil is excessively dilated at night and you complain about poor night-time vision, your ophthalmologist will opt for this personalized technique. When a thorough analysis with an aberrometer shows that variations are quite significant, your doctor may decide that Custom LASIK is the perfect solution for you. Following this laser treatment, you will notice an improvement in your night-time vision when driving and you will also find that contrasts become more pronounced. You will also be less troubled by halos around objects. In about half of the cases, we find that patients improve by 1 or more lines when reading the Snellen chart. In other words, we actually manage to create “eagle eyes“.

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The corneal flap is created in the same way as in the LASIK procedure.

The aberrometer measures all optical system aberrations from the cornea to the lens and right through to the corpus vitreum. Below, you can see a picture of the measured wavefront in a perfect versus an imperfect eye.

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PRK

In this procedure, the laser beams target the superficial epithelial layer. Following the treatment, a soft contact lens is inserted into the eye which must be worn for about three days. Recovery is slower than with LASIK treatment and it will also take a little longer for sight to return. Your doctor may opt for PRK if your cornea proves to be too thin for LASIK treatment, for instance. Both eyes can be treated during one and the same session. We opt for this treatment in about 15% of cases.

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PTK

This is a therapeutic laser procedure used to treat recurrent corneal erosion. The laser polishes the fine Bowman membrane layer in order to prevent a tearing of the cornea. Following the treatment, the patient is given a contact lens. Sight only recovers after a few days.

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The fold you can see above the pupil is a definite sign of corneal erosion.

Bioptics

This combined lens implant and laser technique allows us to treat short-sightedness of more than -9 D and long-sightedness of more than + 4 Dioptre.
First of all, the lens is implanted into one eye under drop anaesthesia. The lens you can see in the picture clicks onto the iris by means of two little clips. In principle, the second eye can be operated on one week later. Six weeks later, the remaining refraction to both eyes is corrected by means of LASIK in one single session. Photograph of an Artisan lens

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We mostly implant an ICL (Implantable Collamer Lens) lens, which is a very thin, flexible lens and is positioned right in front of the anterior capsule of the patient’s own lens, behind the pupil in other words. This lens does not have any clips and is supported by the zonular fibres of the patient’s own lens. It can be used to correct severe myopia or severe hypermetropia. In this procedure, no suturing is required. Any remaining refraction can subsequently be corrected by LASIK. 1 to 3% of patients may, in time, develop cataract. However, this procedure is reversible.
This particular lens can also be used to treat myopia in patients suffering from keratoconus.
We have our own Vumax echograph which allows us to portray eye structures with extreme accuracy so that the diameter of the lens can be determined with the utmost precision. We can now also implant toric ICLs, which enable us to correct both myopia and spherical aberrations in the eye.

Photograph of implantable contact lenses.

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The ICL lens does not come into contact with the patient’s own lens.

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Watch the video

Corneal transplants

When the cornea becomes cloudy, vision can become so hazy that your ophthalmologist may decide that you need a new cornea. The cornea is obtained from a cornea bank and has been harvested from a recently deceased donor. There are several reasons why the cornea may become cloudy. In most cases, patients are suffering from keratoconus, a congenital disorder, which causes the cornea in one sector to become thinner, displaying a very steep curvature as a result. By means of corneal topography, the ophthalmologist is able to diagnose this condition.
Other causes of a cloudy cornea may be:
• Loss of endothelial cells years after the patient has undergone cataract surgery combined with an anterior chamber lens implant.
• Corneal dystrophy…

The procedure itself

The operation is performed under general anaesthetic and takes about one hour. We essentially use a trephine to remove the diseased cornea before attaching the new cornea so that visual acuity is restored.

What can you expect following this procedure?

Recovery takes about 1 month. You will need to apply cortisone drops to the eye 6 times a day to prevent the graft being rejected. You will also need to apply a hydrating eye gel.