Introduction  

Femtosecond laser-assisted in situ keratomileusis (Femto-LASIK) is a type of LASIK that corrects refractive error without using a microkeratome (blade). Femto-LASIK treats mild, moderate, and high myopia as well as hyperopia and astigmatism. The procedure uses two lasers, an infrared laser to create a LASIK flap, and an excimer laser for refractive ablation. It is the most modern LASIK method that is said to improve the flap's geometry with limited LASIK complications. Reports indicate that it is the most used laser procedure in the US due to fewer complications.

Femto-LASIK is said to offer the surgeon full control with better precision. Besides, it has the advantage of amplified predictability, increased safety, painless, and effective. Besides, it is said to be the only LASIK procedure used to treat hyperopia. 

Femto-LASIK also has other applications besides flap creation which include:

  • Wound construction
     
  • Presbyopia correction
     
  • Astigmatic keratotomy
     
  • Femtosecond lenticule extraction
     
  • Small incision lenticule extraction
     
  • Capsulorhexis in cataract surgery
     
  • Intrastromal presbyopia correction
     
  • Nuclear fragmentation in cataract surgery 
     
  • Cutting of donor buttons in endothelial keratoplasty
     
  • Customized trephination in penetrating keratoplasty
     
  • In laser-assisted anterior and posterior lamellar keratoplasty
     
  • Channel creation for implantation of intrastromal corneal ring segments
     

Candidates for Femto-LASIK include those aged over 20 who are in good health. Their refraction should have been stable for two years before the procedure. Besides, they should not have had previous eye surgery, disease, or trauma.
 

The following should not undergo Femto-LASIK:

  • Keratoconus patients
     
  • Those with poor compliance
     
  • Those with general diseases
     
  • Pregnant or lactating mothers

 

Also Known As

  • Femto-LASIK
     
  • All-laser LASIK
     
  • Bladeless LASIK
     
  • Blade-free LASIK

 

Types

Femtosecond LASIK platforms and procedures include:

  • Victus
  • iLASIK 
  • VisuMax
  • VisuMax 
  • Femto LDV 
  • IntraLase 60 kHz 
  • Femtec (20/10 Perfect Vision AG)

 

Before the Procedure

The eye surgeon or specialist meets with the patient ahead of the procedure to discuss options and determine whether it’s a suitable vision-correcting technique for the candidate. The patient’s medical history is evaluated. S/he should not wear contact lenses two weeks before the ophthalmic examination and two weeks before the procedure.  

The following ophthalmic examinations are made:

  • Keratometry
     
  • Corneal topography 
     
  • Corneal pachymetry
     
  • Mydriatic fundoscopy
     
  • Noncontact tonometry
     
  • Manifest and cycloplegic refraction
     
  • Corrected distance visual acuity (CDVA)
     
  • White-to-white (WTW) corneal diameter
     
  • Uncorrected distance visual acuity (UDVA)
     
  • Anterior segment slit-lamp biomicroscopy
     

On the day of the surgery, the usual protocols should be observed, such as not eating from midnight going forward on the eve of the procedure. Patients should not wear any eye makeup, jewelry, or hair that might interfere with head position. The procedure should take only a few minutes for each eye, and the patient will need a responsible adult to drive them home afterward.
 

Procedure

The procedure is performed under local anesthesia after which the surgeon:

  • Centers a suction ring over the pupil and applies suction
     
  • Stabilizes the eye and flattens the cornea using an applanating glass contact lens
     
  • Administers the femtosecond laser treatment to create the flap
     
  • Releases suction and passes a spatula across the flap
     
  • Uses an excimer laser for ablation
     
  • Places a bandage contact lens

 

Risks & Complications

Despite being a safe and effective procedure, Femto-LASIK can present with the following risks and complications:

  • Haze
     
  • Flap melting
     
  • Flap dislocation
     
  • Dry eye syndrome
     
  • An incomplete flap
     
  • Night visual disturbance
     
  • Reduced contrast sensitivity
     
  • Decreased corneal sensitivity
     
  • Wrinkles in the flap (flap striae)
     
  • Diffuse lamellar keratitis (flap inflammation)
     
  • Epithelial ingrowth (corneal epithelium grows in an area it shouldn't)
     
  • Keratectasia (abnormal corneal bulge caused by scarring and thinning)
     
  • Transient light sensitivity syndrome (TLSS) which is characterized by the onset of photophobia. It occurs 2-6 weeks following the procedure and is treated with steroid eye drops

 

Aftercare & Recovery

Thirty minutes after surgery, the surgeon will check the flap position at the slit lamp. Usually, visual acuity rehabilitation is immediate, and the patient can see clearly. 

The first follow-up visit is scheduled for the day after surgery, where the surgeon removes the bandage contact lens. The next follow-up visit will be after one month, then after three months. Subsequent appointments should be at six months, then at 12 months. During each visit, the CDVA, UDVA, noncontact tonometry, and manifest refraction are measured. A slit-lamp examination is also done. After a month, the doctor will perform a topography. The topography is also performed at six months and one year.
 

Outcome

Femtosecond laser results in a thinner corneal flap that enables the surgeon to correct refractive error. Femto-LASIK is effective and safe in correcting myopia. Studies have shown that the results are stable, with no significant postoperative CDVA and UCVA differences.