بسم الله الرحمن الرحیم

LDV

Femto-LASIK

Basir Eye CenterDr. Ahmad Shojaei

www.iranophthalex.com

Femto second Laser

• Femto second Laser employs near- infrared pulses to cut tissue with minimal collateral tissue damage (mode-locked, diode pump, neodymium- glass laser)

• Infrared wavelength range, at 1053 nm

• It uses a spot size of less than 3 micron

• Produces tissue disruption at a specified and precise level within the corneal stroma

• Femto second has different applications in ophthalmology• Its major use at present is cutting flap in LASIK surgery

Femto LASIKGeneral Comments

• The most common application of femto second • Introduced in 2002 • Started in practice 2006 • Allow light to pass from the tissue without damage to

the tissue

Femto LASIKPatterns

• Raster or spiral pattern→ bed• Peripheral circular →posterior-anterior

Femto LASIK

Femto LASIK

Femto LASIKFlap creation

• The depth of the flap is typically set at 100±10 micron

• Studies have shown that the

standard deviation of flap thickness is around 14.

• The flap diameter is typically set to about 9.0mm.

Femto LASIKMajor advantage

femto second overmicrokeratome

• Flap criteria• Accuracy of flap thickness• Refractive outcome• Capability and choice of -Cutting thin flap (90 µm)

-Different diameter,

-Hinge position

-Hinge length• Safety and predictability• Absence of moving parts• ↓Complications• Improved staff and physician satisfaction

Femto LASIKFlap criteria

• Quality of flap edges• More regular (flap and Bed)• Peripheral and Center

Femto LASIK

Femto LASIK

Femto LASIK

Femto LASIK

Femto LASIK

Femto Lasik

• Accuracy of flap thickness (Actual and expected)

• LDV→depth→90→100→110→140 micron• By change of inter shield• α< 5% variation 107.43±4.70 µm• Hansatome 125.90±17.5 µm

Femto LASIKRefractive outcome

• UCDVA≥20/20 91.7% →Femto LDV

88.5% →Handsatome

RE Femto LDV →+0.5 Diopter →Plano

87.5%

Handsatome→ +0.5 Diopter →Plano

84.6%

Femto LASIKPossible Advantages

• Fewer higher order aberrations• Less astigmatism• Better contrast sensitivity• Less epithelial ingrowth• Lower enhancement rate• Less dry eye

Femto LASIKDisadvantages

• High price• Large physical size• Lack of portability• Speed and the time needed to prepare the

flap

Femto Lasik

• Surgical technique and operation

-Pre operation evaluations

-During operation

-After operation

Femto LASIKSurgical technique

• Pre-op evaluation

-Patient selection

-Machine preparation

-depth

-size

-hinge

Femto LASIKSurgical technique

• During operation

-Patient's position

-Hand piece position

-Centering

-Suction (enough IOP)

-Laser

Femto LASIKSurgical technique

• After operation

-edge release

-lifting of the flap

-ablation

-repositioning of the flap

Femto LASIKSurgical technique

• Special points

-Suction release and re cut

-Bridges

-Gas bubbles

-IOP

-Duration

Femto LASIKSurgical technique

• Gas bubbles

-interface →Opaque media

-rare →deep stroma → tracker

-rare → subepithelial loss of vacuum

Button hole

-rare → Between cornea and hand piece

-rare → in A/C

Femto LASIKIOP During flap preparation

• Intralase → 135±6mm Hg• Visual Max → 65±20mm Hg• Femtec → 205±32mm Hg• Femto LDV→ 184±28mm Hg• Maximum IOP → 260±53mm Hg in

interlase

Femto LASIKSurgical technique

• Duration:

*Cutting time:

-Femto LDV 25 seconds

-Intralase 31 seconds

*Suction time:

-Femto LDV 82±22 seconds

-Intralase 70±15 seconds

Femto LASIK

Femto LASIK Movie

Femto LASIKComplications

• Absence of usual complications

-Buttonhole

-Small flap

-Free caps

-Irregular cut

-…………….

Femto LASIKComplications

• Suction breaks• Incomplete flaps• Thin flaps, tears• Increased postoperative inflammation• Persistent bubbles• Decentered flaps• Slipped flaps

Femto LASIKSpecial complications

• TLSS (transient light sensitivity syndrome)• Gas bubble• DLK (lamellar inflammation)• Glare

Femto LASIKTLSS

• Occur days to weeks after femto second • Extreme photophobia• Good V.A • Absence of clinical findings• Response of keratocyte• Inflammatory response to surrounding

tissue to gas bubble• Topical corticosteroid

Femto LASIKIn special case

• Post Lasik –PRK• Post R.K- A.K• Corneal scar• Post P.K

Thank You