بسم الله الرحمن الرحیم
LDV
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