Intralase vs Microkeratome

To help you appreciate the critical differences between the more advanced Intralase All-laser Method and the older out-dated Microkeratome blade technique, we’ve prepared this table to summarize a few of the most important factors.  Desirable features are highlighted in "green", less desirable in "yellow" and least desirable in "red".
 

 

Intralase Femtosecond Laser System

Microkeratome

Computerized control of corneal flap thickness

Yes - Surgeon able to control to within 10 microns

No computer control - Surgeon must rely on manufacturing tolerances on steel blades with typical tolerance of 20 to 30 microns at best

Computerized control of flap diameter

Yes - Surgeon able to control within 100 microns

No - Surgeon must hope that flap diameter is adequate for the planned ablation

Computer adjustment of flap centration

Yes - Surgeon able to control centration using software controls

No - Centration is dependent on surgeon and variability of vacuum positioning of suction ring on the eye. Can result in decentered flap that will compromise the visual result

Flap Characteristics

Planar flap induces few if any new optical aberrations

Meniscus flap architecture induces new visually significant optical aberrations

Surface Characteristics of Stromal Bed

Very smooth on scanning electron micrographs

Blade chatter creates irregular surface characteristics on scanning electron micrographs

Sidewall architecture

Vertical sidewall promotes better healing and less flap slippage

Meniscus edge heals less aggressively with increased risk for flap slippage and dislocation

Flap healing and adhesion to the eye

Extremely good adhesion - Many flaps are difficult to relift within months making the eye more structurally sound

Poor healing and adhesion - flap can be easily lifted many years after the primary procedure

Risk for epithelial ingrowth

Extremely rare if not non-existent

Common - occurs in 1 to 2% of primary cases and more common in retreatments - can be difficult to eradicate - causes pain, dryness and can compromise vision

Risk for free flap

Highly remote - never reported in over 1 million procedures

Yes - if occurs can have severe visual results

Risk for "button hole" flap (flap with a hole in the middle)

No

Yes - occurs 1/1000 - requires surgery be aborted and recut in 3 months or otherwise undergo a complex PRK procedure

Risk to patient if vacuum is lost during surgery

No problem - vacuum ring is reinserted and procedure is immediately repeated without incident or sequelae

Yes - may cause a defective flap. Treatment must be aborted for at least 3 months and patient may have permanent injury in rare cases

Risk for partial flap or short flap

No problem - vacuum ring is reinserted and procedure can be repeated immediately without incident or sequelae

Yes - occurs 1/2000 - requires that surgery be aborted and recut in 3 months or otherwise undergo complex PRK procedure

Risk for epithelial defect or sloughing

Extremely rare

Common - occurs in 1 to 2% of primary cases.  Results in slow visual recovery, unpredictable refractive endpoints and predisposes to epithelial ingrowth

Risk for Diffuse Lamellar Keratitis (DLK)

Rare

Rare

Risk for Transient Light Sensitivity (TLS)

Transient sensitivity to light - easily treated with eye drops - Extremely rare with new 60 KHz system - Does not cause problems with vision, is not permanent and has no long term sequelae

Never reported