Femto-LASIK (Femtosecond Laser, IntraLASIK)

Who Can Have Femto-LASIK?

• Those aged 18 or over
• Those whose prescription has been stable for the past year
• Those with up to 8–10 dioptres of myopia, or up to 5–6 dioptres of hyperopia or astigmatism
• Those with a normal corneal map (tomography)
• Those whose cornea is thick enough (usually a thickness of more than 500 microns is needed)

Who Cannot Have Femto-LASIK?

• Pregnant or breastfeeding women
• People with uncontrolled diabetes
• People with rheumatic diseases (collagen tissue diseases)
• People with AIDS
• People with keratoconus (a cornea that is thinner and more cone-shaped than normal)
• Severe dry eye
• Cataract

What to Do Before Femto-LASIK

If you wear contact lenses, you need to stop wearing soft lenses 5 days and hard lenses 15 days beforehand.

Eye Tests Before Femto-LASIK

• Measuring vision with and without glasses
• Computerised measurement of the prescription
• Determining the prescription
• Biomicroscopy: examination of the eye under a microscope
• Corneal topography (mapping of the cornea)
• Pachymetry: measuring corneal thickness
• Wavefront analysis: measuring the amount of “aberrations”, the defects in the eye that reduce the quality of vision
• Tonometry: measuring the pressure inside the eye
• Pupillometry: measuring the size of the pupil
• Dilated fundus examination: examining the retina (nerve layer) of the eye with the pupil dilated

How Femto-LASIK Is Performed

LASIK is applied to the cornea, the clear front layer of the eye. It takes a total of 15 minutes for both eyes.

• The eye is numbed with anaesthetic drops.
• The area around the eye is cleaned and covered with a sterile drape.
• To prevent blinking, the eyelids are held open with an instrument called a “lid speculum”.
• A thin flap is cut in the cornea with a “femtosecond” laser.
• The flap is lifted, and the laser is applied underneath it to give the cornea a new shape.
• The flap is laid back down.
• After waiting about a minute, the flap adheres in place by itself.
• Antibiotic drops are put in the eye.
• The lid speculum is removed and the procedure is complete.

After Femto-LASIK

The eyes are not bandaged after the procedure; only protective glasses are worn.

• A final eye check is done half an hour after FemtoLASIK, after which you can leave the hospital.
• For 3–4 hours after FemtoLASIK there is burning, stinging, watering, sensitivity to light and a need to keep the eyes closed.
• Vision becomes clear 3–4 hours after FemtoLASIK.
• Driving, wearing make-up and bathing are possible from the next day.
• Eye check-ups after Femto-LASIK: the next day, after 1 month and after 3 months
• Eye drops: Antibiotic and steroid drops are used for one week. Artificial tears are recommended for 3–6 months.

Success Rates of Femto-LASIK

Not everyone who has Femto-LASIK ends up with a prescription of exactly zero. Out of every 100 people who have LASIK, 95 can see fully without glasses, while 5 may need thin glasses. (This rate varies with the type of refractive error, the prescription and the structure of the eye.)

Possible Complications of Femto-LASIK

• Residual prescription (under- or over-correction)
• Blood on the white of the eye: this can develop because of the suction ring used during Femto-LASIK. It is a cosmetic problem that lasts a few weeks, clears by itself without leaving a trace and does not affect vision.
• Diffuse lamellar keratitis (DLK), or “Sands of Sahara” (SOS): an allergic-type reaction with many different causes. It is not possible to predict in advance who will develop it. It is not related to allergic conjunctivitis; people with allergic complaints before laser treatment are not more likely to develop DLK. DLK shows itself as haziness of the cornea. Depending on its degree, the person may not notice it at all or may see as if through fog. It is treated by switching to stronger steroid drops than those normally used after laser, or by rinsing the eye with saline in the laser room. Its downside is that it requires one or two extra eye check-ups. It clears within a week with drops or rinsing.
• Ectasia after LASIK: a change in the shape of the cornea caused by excessive thinning. Ectasia develops if laser is applied to an eye whose corneal map and thickness are not suitable. Very rarely, it can also develop after laser treatment on a cornea of adequate thickness and structure. It is treated with glasses and contact lenses; intracorneal ring segments or a corneal transplant may also be needed. It is a very rare complication, but one that should be known before deciding on Femto-LASIK.