Femtosecond Laser Technology

1. Femtosecond Laser Technology

2. Femtosecond Lasers • IntraLase (Abbott) • VisuMaxfemtosecond laser (Zeiss) • Zeimer LDV (Zeimer)

3. Microkeratome Most Commonly Used * DUFFEY 2008

4. The disposable docking suction ring is positioned on the eye & suction applied IntraLASIK™

5. Tear Film Epithelium Bowman’s Stroma Descemet’s Endothelium IntraLase Laser Procedure • Glass Lens applanates cornea to flatten eye & maintain precise distance from laser head to focal point Glass Applanation Surface Cornea

6. Benefits of IntraLase versus Microkeratome • Less Risk • Flap complications • Corneal abrasions • More Precise • Flap is more precise • Thickness • Diameter of flap • Better Outcomes • Better Visual Acuity • Less Dryness

7. Flap Complications • Relatively unusual complication but can be devastating • Buttonhole flap • Free cap • Incomplete flap • Corneal perforation

8. Corneal Abrasions • Microkeratome transcends across the cornea, rubbing up against the epithelium • Risk factors for developing abrasions • EBMD, older patients, fair skin, smokers • Kerizian and StonecipherJ Cataract Refract Surg 2004; 30:804-811 • Loose Epithelium • 9.6% for Moria • 7.7% for Hansatome • 0.0% for IntraLase

9. Corneal Abrasions • The IntraLase laser merely docks upon the cornea rather then rubbing across the cornea

10. Mechanical Keratomes Principles of Operation The keratome flattens the cornea & the oscillating razor blade cuts a circular flap of tissue = “x” microns Flap thickness is determined by the gap between the blade & the footplate

11. Flap ThicknessKerizian and StonecipherJ Cataract Refract Surg 2004; 30:804-811 • Mean Flap Thickness: • 114 m (SD 14m) for Intralase (130m) • 153 m (SD 26m) for Moria (130m) • 156 m (SD 29m) for Hansatome (180m) • IntraLase Flap has a more reliable thickness • Thinner Flap • Lessens the risk of a thin post-operative cornea • Keratectasia • Leaves more room for enhancement surgery • Flap lift

12. Side Cut Flap Edge • Edge of flap • Flap fits back in place • Manhole cover • Less risk of epithelial ingrowth on primary and enhancement procedures

13. IntraLase Laser gives Better Vision? • More precise correction of astigmatism • Kerizian and StonecipherJ Cataract Refract Surg 2004; 30:804-811 • Less high order aberrations • Tran et.al. J Cataract Refract Surg 2005 31;97 – 105 • Controversial

14. Visual Outcome • Montes Mico R, Et al. Femtosecond Laser versus Mechanical Keratome for Myopia. Ophthalmology 2006;114(1):62-68. • Slightly better visual results • Better results in high spacial frequency contrast sensitivity • Greater percentage of patients within intended target +/-0.50 D • IntraLase laser created fewer higher order aberrations • Lim found no difference in visual results • Lim . Comparisons of Intralase and mechanical microkeratome for LASIK. Am J Ophthalmol.2006;141:833-9

15. IntraLase Flap is Planar • Planar Flap: IntraLase • Uniform thickness • Induce less astigmatism • Induce less high order aberrations • Meniscus Flap: Microkeratome • Thinner in center then periphery

16. Interface Bed is Dryer • Lessens risk of irregular ablation because of dryer bed SEM image of 110 μm flap at 13X courtesy of Dan Tran, MD

17. Less Dryness • IntraLase laser separates the corneal lamellae versus cutting nerve fibers with a blade • Durrie et. Al.ASCRS - April, 2005 • Compared microkeratome versus IntraLase Laser • Schirmers, staining and corneal sensation were better with IntraLase at 1, 3 and 6 months • Lim T .Comparison of the IntraLase femtosecond laser and mechanical microkeratome for LASIK. Am J Ophthalmol.2006:141(5):833-9. • Corneal sensation returned faster with IntraLase vs Microkeratome

18. Patients who benefit from IntraLase • Patients at risk for microkeratome complications • Steep and thin corneas • Buttonhole flaps • Very flat corneas • Free Caps • Blepharospastic patients • Higher risk for abrasions • Older • Fair skin • Subtle EBMD

19. Patients who Benefit from IntraLase • Higher risk for dryness • Low Schirmer’s • History of dryness • Patients who are risk adverse • Patients who have thin corneas

20. Disadvantages of IntraLase • Increased cost • Transient Light Sensitivity Syndrome (TLSS) • Longer procedure time • Opaque bubble layer may occur • Gas bubbles in the anterior chamber • Flaps do not look as good • Meibomian secretions • Flap edge

21. IntraLase Edge is More Prominent

22. IntraLase Flap Margin • Hyperreflective fibrils at flap margin • Indicates a stronger wound healing response • Sonigo et al. In vivo corneal confocal microscopy comparison of IntraLasefemtosecond laser and mechanical microkeratome for LASIK. Invest Ophthalmol Vis Sci. 2006;47:2803-11.

23. Transient Light Sensitivity Syndrome • 1 in 1000 cases • Eyes become very sensitive to light • No ocular findings • Presents 3-6 weeks post-operatively • Treat with high dose topical steroid • Resolves without complications • May be related to higher energy absorbed into anterior chamber • Related to energy level of femtosecond laser

24. Other Uses for IntraLase • Lamellar keratoplasty • Corneal Intacs • Corneal channels

25. My Experience • Initially saw increased rate of DLK • Increased energy • Initially had increased incidence of flap slips • Unknown etiology • Possible eyedrop usage • Visual outcomes same • Maybe less dryness • Less incidence of complications • Flap complications • Abrasions • Epithelial Ingrowth

26. My Experience • Co-managing doctors did not embrace new technology • No increase in volume • Price per patient went up • Surgeon loves it!