Femtosecond lasers emit extremely short pulses that can precisely cut tissue without damaging surrounding areas. They are used for cataract and refractive eye surgery. For cataracts, the laser creates incisions and fragments the lens for removal. For refractive surgery, it cuts corneal flaps and lenticules, improving precision over mechanical methods and reducing complications. While increasing costs and complexity, femtosecond lasers provide improved safety and accuracy for vision correction procedures.

1. Femtosecond Laser
 Femtosecond – SI unit of time ( 10-15 of a Second )
 Femtosecond Laser emits optical pulses with duration in the
domain of femtoseconds
 Current delivery system – Use Neodymium:glass 1053
wavelength light
 Focus light at spot size 3 micron

2. Mechanism of Action
 Principle of photodisruption
 Laser energy is absorbed by
tissues which result in
plasma formation
 Expansion of plasma creates
cavitation bubbles which
separates the tissue plane

3. Micro vs Femto second laser

4. Femto second laser assisted cataract
surgery
 Femtosecond laser first FDA approved for cataract surgery in
2010.
 With guidance systems it is used to make-
 Cataract clear corneal incisions
 Capsulorhexis
 Lens fragmentation/softening

5. Preoperative evaluation
Special attention to
• Corneal opacities
• Arcus senilis
• Pupil size
• Zonular dehiscence
• Grade and type of cataract
• Patient should be told that operating procedure may take
place in two different rooms

6. Anaesthesia
 Topical is preferred
 Encourage to look at fixation light
 Peribulbar blocks may cause chemosis and hinder docking
 GA in very young children

7. Instrumentation
 Alcon LenSx
 AMO Catalys
 Technolas Victus
 LensAR
 Three basic instrumentaion-
1. Patient interface
2. Laser delivery
3. Imaging system

8. Patient Interface
3 basic function
 Maintain positional and mechanical stability of eye
 Coupling device to facilitate laser delivery
 Permit acquisition of images
Two types
 Applanating ( LenSx and Victus )
Small diameter
Suitable in small palpebral aperture
 Nonapplanating ( Catalys and LensAR )
Cause less increase in IOP
Less SCH

10. Imaging system
 Imaging system based upon-
Spectral domain optical coherence tomography
3-dimensional confocal structural illumination

11. Imaging System
 Most important step is centering the cornea
 Corneal incisions and capsulorhexis

12. Capsulorhexis
 Ideally centered on limbus
 Can be centered on pupil ( set to 5mm )

13. Lens fragmentation
 4-8 segments
 Concentric pattern in softer cataracts
 Grid pattern in harder cataracts
 Done before making the corneal incisions

14. Planning Station
Incisions
 Position of primary and secondary incisions according to
surgeon’s convenience
 Can be according to pre-op astigmatism
 Followed by Phacoemulsification

15. Contraindications
Small palpebral aperture
 Interface diameter 11.5 to 15.5mm
 Can be overcome by lateral canthotomy
Neck and back problem
 Optimal docking, imaging and laser delivery need patient to
lie flat
Nystagmus and attention deficit disorder
 Not able to comply instructions and fixation
Glaucoma
 Rise in IOP 10-20 mmHg

16. Contraindications
Corneal opacities
 Hinder in imaging
Subluxated/Dislocated lens
 Nucleus management not possible
 Corneal incision can be made
 Liquefied lens material hinders laser penetration and
incomplete capsulorhexis
Small Pupils
 Relative contraindication
 Pupil expanding devices
 No air bubble should be in the AC

17. Unique Complications
Machine related
 Errors in software or hardware
 Stop/reattempt
 Switch over to conventional Phaco
Loss of suction
 Improper docking/excessive eye or head movement
 Hard head rest are preffered
 If occurs during capsulorhexis , complete manually
SCH
 More in applanation type

18. Unique Complications
Pupillary constriction
 Miosis of 2-3 mm
 Applanation/laser energy
Incomplete capsulotomy/Anterior capsular tear
 Corneal folds/lens tilt/eye movements while firing laser
Capsular block syndrome
 Intraoperative capsular block with subsequent rupture
during hydrodissection
 Nucleus can be rotated by pneumodissection ( air bubbles
produced by laser delivery )

19. Advantages
Incisions
 Greater stability
Capsulotomy
 More precise
 Better IOL centration

20. Advantages
 Nucleus management and phaco energy
- Reduced ultrasound energy
- Reduced effective phaco time
 Zonular weakness
- Reduced stress on zonules during capsulorhexis and nucleus
chopping
 Mild decentration capsulorhexis can be centered on lens
 Posterior capsulorhexis
 In infants
 Macular edema
 Lesser edema in comparison to phaco

21. Disadvantages
 Cost
 Training of staff – calibrate and operate the machine
 Operating room – shifting of patient may be inconvenience
 Time – two step procedure, takes longer time then phaco
 Increased expectation- more expensive more expectations

22. Femto Second Laser Refractive Surgery
 Femtosecond laser first FDA approved for LASIK flaps in
2001
 1st released commercial device was: Intralase FS™ (Abbott
Medical Optics, Abbott Park, Illinois);
 Femtec® (20/10 Perfect Vision, Heidelberg, Germany);
 VisuMax Femtosecond System® (Carl Zeiss Meditec, Jena,
Germany);
 Femto LDV™ (Ziemer Group, Port, Switzerland); and
 Wavelight FS200®

24. Intralase Femto lasik
 Technique:
 The suction ring is centered over the pupil.
 The docking procedure is then initiated while keeping the
suction ring parallel to the eye.

25. FemtoSecond laser treatment

27. Flap raised with blunt spatula
 Suction is then released.
 A spatula is carefully passed across the flap starting at the
hinge and sweeping inferiorly to lift the flap for excimer laser
ablation.

28. Advantages:
 Reduced incidence of flap complications like buttonholes,
free caps, irregular cuts , wrinkles as seen in LASIK.
 Diffuse lamellar keratitis

29. Advantages
 Decreased incidence of Subepithelial Haze
 Epithelial ingrowths

30. Advantages
 Control over flap diameter and thickness, side cut angle,
hinge position and length.
 Increased precision with improved flap safety and better
thickness predictability.
 Capability of cutting thinner flaps to accommodate thin
corneas and high refractive errors.
 Stronger flap adherence.
 Less increase in IOP required
 Lesser incidence of dry eye.
 Lesser hemorrhage from limbal vessels.
 The ability to retreat immediately if there is incomplete FS
laser ablation.

31. Disadvantages:
Opaque bubble layer (OBL):
 Gas bubbles routinely accumulate in the flap interface during
FSL treatment
 May dissect into the deep stromal bed(obscuring excimer
laser tracker)
 Reach AC, or escape to subepithelial (resulting in button
hole).

32.  Patients present with extreme photophobia and good visual
acuity
 Proposed mechanism is either an inflammatory response of
the surrounding tissue to the gas bubbles or biochemical
response of the keratocytes to the near-infrared laser energy
 Resolves without sequel but requires aggressive topical
steroids for weeks.
 Micro-irregularities on the back surface of the FSL LASIK
flap can cause “rainbow glare”

33. Rainbow glare

34. Disadvantages
 Photodisruption-induced microscopic tissue injury and
ocular surface inflammatory mediators may cause lamellar
keratitis in the flap interface.
 Increased difficulty in lifting the flap if retreatment is
required after that (because of good adherence).
 Increased cost.
 Moving the patient between 2 laser instruments.

35. Intrastromal lenticule extraction
 ReLEx (refractive lenticule extraction)
 Performed exclusively with a femtosecond laser system, i.e., no
excimer laser is needed.
 Steps:.
The femtosecond laser is used to cut a small lens-shaped
segment of tissue (lenticule)within the center of the cornea..
 Made in the anterior cornea with the laser — similar to the
flap created in LASIK.
 The flap is lifted and the lenticule is removed and discarded..
 The flap is repositioned
 The removal of the lenticule reduces the curvature of the
cornea, thereby reducing myopia.

37. SMILE
 A variation of ReLEx is another investigational procedure
called small-incision lenticule extraction (SMILE).
 In the SMILE procedure, a corneal flap is not created.
 A small incision is made in the mid-periphery of the
cornea with the laser, and the lenticule is removed through
this self-sealing incision.
 The SMILE procedure has additional potential advantages.
 No corneal flap is created, SMILE may pose less risk for
post-surgical dry eye and ectasia than ReLEx or LASIK.
 No risk of flap displacement from trauma to the eye after
surgery.

38. SMILE
 The promising early results of ReLEx and SMILE suggest
they may someday become a popular alternative to LASIK for
vision correction.
 However, currently it is not possible to perform these
procedures for small amounts of ametropia, as typically
present in enhancement surgery, because the lenticule
would be too thin to manipulate safely.

39. Intracor