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FLACS ie Femtosecond Laser Assisted Cataract Surgery - Unbiased Review..

laser cataract surgery

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FLACS ie Femtosecond Laser Assisted Cataract Surgery - Unbiased Review..

  1. 1. Revolution, Evolution, or No Solution? Making Sense of the Literature Ken Lipstock, M.D. Richmond, Virginia
  2. 2. emtosecond laser provides an ultrafast burst of energy. •Argon, excimer, and Nd: YAG lasers: nanosecond (10 ) pulses •Femtosecond: 10 second •Excimer: “photoablates” •Argon: “photocoagulates” •Nd: YAG and Femtosecond: “photodisrupt”. Their light energy can be absorbed by optically clear tissue and create “microcavitation bubbles” that cause an acoustic shock wave that incises the target tissue. -9 -15
  3. 3. Femtosecond laser’s ultrafast pulse allows smaller amounts of energy to provide similar power output to the NdYag. This results in much smaller cavitation bubbles therefore reduced “collateral damage” to adjacent tissues.
  4. 4. Femtosecond laser first FDA approved for LASIK flaps in 2001 and then approved for cataract surgery in 2010. With guidance systems (OCT or Scheimpflug-like technology) it is used to make:  Cataract clear corneal incisions and limbal relaxing incisions  Capsulorhexis Lens fragmentation/softening; a pretreatment prior to phacoemulcification and/or irrigation/aspiration.
  5. 5. Mistrust but Verify We are witnessing one of the most intense marketing campaigns ever in Ophthalmology. And this is a sentence from a scientific study in a respected peer reviewed journal! Is Femtolaser Cataract Surgery “the most important evolution since the transition to phacoemulsification?” Much has been claimed but how much is substantiated? In the following presentation I will review the literature to try to shed some light on the subject. Since the vast majority of journal articles are written by those with financial ties to the femtosecond companies, the authors of the journal articles will be color coded red for financial ties and green if not. (The lead author will be in red if at least one of the authors has financial ties.) “It has automated, computer-guided laser precision with minimal collateral tissue damage......with emerging evidence of ......greater precision and accuracy of the anterior capsulotomy, and more stable and predictable positioning of the intraocular lens.”
  6. 6. Company Mode of docking Imaging LensSx Alcon, Ca. Curved glass at first, now uses soft contact interface OCT LensAR Privately Held Orlando, Fl. 2 piece non contact interface Scheimpflug-like Catalys AMO, Ca. Liquid-optics interface OCT Victus B & L Curved glass interface OCT
  7. 7. Capsulorhexis Hypothesis: a capsulorhexis (rhexis) should overlap the IOL optic approximately .5 mm symmetrically 360 degrees and be larger than 4 mm . This will give a better and more consistent effective lens position (ELP) because of less asymmetric contractile force from the fibrosing anterior capsule on the IOL. The IOL should then not position more anteriorly or posteriorly than anticipated or with decentration or tilt. A better ELP leads to: 1. Closer to targeted spherical equivalent and less cylinder a. Better uncorrected distance vision (UCDVA) 2. Less higher order aberrations like spherical aberration and tilt a. Better corrected distance vision (CDVA) b. Better quality of vision with less glare, halos, and better contrast sensitivity. 1,2,3
  8. 8. Claim of the Femtolaser Companies: The femto anterior capsulotomy is more precise (consistent) and more accurate than a manual curvilinear capsulorhexis (CCC). Better size, more circular, better centered thus better overlap of the IOL. And better overlap yields less IOL decentration and tilt and better anterior-posterior position. 4,5 4 5 Assymetric Overlap Decentered IOLCCC vs. Femto Buttons Friedman; JCRS; 2011 Kranitz; JRS; 2011
  9. 9.  Continuous curvilinear capsulorhexis (CCC) technique was developed simultaneously by Neuhann in Germany and Gimbel in Canada around 1987. 6,7  Prior rhexis techniques (eg. can opener) led to 100% anterior capsular tears during cataract surgery and CCC tear rate approached 0%. 8  Prior to CCC capsular tears led to IOL’s with haptics commonly with one in the bag and one in the sulcus or with both in the sulcus.
  10. 10. Continuous Curvilinear Capsulotomy: A Revolutionary Change for IOL Positioning 9 Assia, Apple (Oph 1993) showed:  Bag-Sulcus Fixation mean Decentration= .64 ± .39mm (range up to 1.76mm) Note: 1 SD =66.6% thus: 1.0mm decentration was common  Bag-bag Fixation mean Decentration= .18 ± .09
  11. 11. IOL Mean dec. Mean tilt Akkin (1994) 0.15 1.1 Hayashi (1997) MZ60BD 0.27 ± .15 2.62 ± 1.33 SI30NB .30 ± .16 2.53 ± 1.36 MA60BM .30 ± .15 2.71 ± 1.84 Mutlu (1998) 0.28 ± .14 2.83 ± .89 Kim (2001) MZ60BD 0.31 ± .15 2.67 ± .84 SI-30NB 0.32 ± .18 2.61 ± .83 AcrySof MA60BM 0.33 ± .19 2.69 ± .87 Taketani (2004) AcrySof MA30BA 0.30 ± .17 3.43 ± 1.55 Baumeister (2005) CeeOn 911A 0.24 ± .13 3.03 ± 1.79 PhacoFlex SI-40 0.23 ± .13 3.26 ± 1.69 CeeOn 911A 0.29 ± .21 2.34 ± 1.81 AcrySof MA60BM 0.24 ± .10 2.32 ± 1.41 Mutlu (2005) AcrySof SA30AL 0.34 ± .08 2.70 ± .55 AcrySof MA30BA 0.39 ± .13 2.72 ± .84 Rosales (2006) UNKNOWN 0.25 ± .28 .87 ± 2.16 de Castro UNKNOWN 0.34 ± .19 2.34 ± .97 Baumeister (2009) AR40C 0.19 ± .12 2.89 ± 1.46 Z9000 0.27 ± .16 2.85 ± 1.36 Hayashi (2014) H60M 0.25 ± .17 4.88 ± 1.45 MA60BM 0.28 ± .16 4.85 ± 1.52 10 Mean IOL decentration 0.28 ± .16 mm and tilt 2.61 ± 1.2° Mean follow-up= 12.2 months Range= 3 to 48 months Clinical Studies in the CCC Era Measuring IOL Decentration and Tilt
  12. 12. How Much Does 0.28 ± .16mm Decentration and 2.6° ± 1.2° Tilt Effect Vision? Let`s look at the Non-Femto Literature first…. Would even less decentration and tilt provide better UCVA and CDVA? Would even less decentration and tilt provide better contrast sensitivity and less glare and halos? Would even less decentration and tilt have more or less effect depending on whether the IOL is spherical, negative aspheric, neutral aspheric, accommodating, multifocal?
  13. 13. Remember: Femto Companies Claim Better Rhexis → Better ELP → Better Vision Better Vision can mean both smaller refractive error and better quality of CDVA. Okada has shown that a better rhexis does NOT lead to a Smaller Refractive Error (spherical equivalent or cylinder.) Okada (Oph 2014) : Does the Rhexis Circularity or Centration effect Post-op Refractive Error?  93 eyes  Phaco mostly by residents  Pre-op spherical equivalent -7.75 to +4.50  Alcon Spherical IOL (SN60AT) Results for One Month and 1 year Measurements:  Rhexis Circularity (comparison to perfect circle; ratio 1.0=perfect)  Rhexis (not IOL) Decentration from pupil center  Complete Overlap of Rhexis (360 over the IOL Optic) yes or no 11
  14. 14. 1 Month mean 1 Year mean  from 1 month – 1 year Circularity .83 ± .01 .87 ± .03 p < .001 Decentration (mm) .30 ± .14 .23 ± .13 p < .001 360° overlap (% of eyes) 88% 90% p = .02 Okada Results (Cont’d): (Stabilization Change from 1 Month to 1 Year) Over time the rhexis became more circular, less decentered and with more overlap.
  15. 15. Circularity of Rhexis  NO significant correlation of circularity with post-op target spherical equivalent at 1 month or 1 year  NO significant correlation of circularity with post-op cylinder at 1 month or 1 year Okada Results (Cont’d)
  16. 16. Decentration of Rhexis NO correlation with change in cylinder from 1 month to 1 year. It did correlate with the change in spherical equivalent between 1 month and 1 year (p=.03). But Bottom Line: NO significant correlation of Decentration with post-op target spherical equivalent at 1 month or 1 year.  NO significant correlation of Decentration with post-op cylinder at 1 month or 1 year. Okada Results (Cont’d)
  17. 17. 360° Overlap vs. Incomplete Overlap → NO correlation with change in spherical equivalent between 1 month and 1 year. It did correlate with change in cylinder between 1 month and 1 year. But Bottom Line:  NO significant correlation of Overlap with post-op target spherical equivalent at 1 month and 1 year NO significant correlation of Overlap with post-op cylinder at 1 month and 1 year Okada Results (Cont’d)
  18. 18.  Rhexis Centration and Circularity and Overlap do not correlate with Post-op Refractive error.  Rhexis Centration and Overlap do play some role in stability of refraction but not enough to effect the average post-op refractive error at one year. Conclusion:
  19. 19. Effect of IOL Position on Quality of Vision Remember, Femto companies hypothesize: Better Overlap → Better IOL Position → Better Vision Okada’s Study Showed: Better Overlap Does Not → Better Refractive Error Question: Could Better Overlap → Better Quality of Vision Lower order Aberrations: myopia, hyperopia, astigmatism Higher Order Aberrations (HOA’s): coma, spherical aberration, trefoil, etc. can effect the quality of vision. These are measured with a wavefront analyzer. Decentration and Tilt may effect Aspheric IOL’s more than spherical IOL’s so we will spend some time reviewing this subject now.
  20. 20. Remember this: The larger the pupil the more HOA’s there are. The pupil size increases in dim light and decreases with age.  55 years old (cataract age) pupil diameter: Bright mesopic= 3.2mm Mesopic= 4.0mm Low Mesopic= 5.0mm 12 Effect of IOL Position on Quality of Vision (Cont’d)
  21. 21.  The First Negative Aspheric IOL was Tecnis (Pharmacia now AMO). Holladay and Piers did the early theoretical research for Pharmacia. Basic Idea: A. The amount of total eye spherical aberration could be manipulated with an IOL because spherical aberration unlike other HOA`s like coma and trefoil is not very sensitive to the position of the IOL (rotation, decentration and tilt). However decentration and tilt could still possibly effect the results. B. The cornea has positive asphericity and this is stable despite aging. It is approximately +.27. The lens has negative asphericity to balance the cornea so the total eye spherical aberration is minimized. The lens becomes more positively aspheric after age 40 causing more total eye positive asphericity. 41 y.o. 6.0mm pupil mean s.a.=.10 65 y.o. 6.0 pupil mean s.a=.19 13 Effect of IOL Position on Quality of Vision (Cont’d) Aspheric IOL’s
  22. 22. A spherical IOL has positive asphericity which increases the spherical aberration of the eye. Pharmacia developed a -.27 negative aspheric IOL (Tecnis) to eliminate total eye spherical aberration and thereby improve the quality of vision eg., contrast sensitivity. Tilt and decentration can induce HOA`s but much more in a negative aspheric IOL than a spherical IOL. Question: Would tilt and decentration be a problem with negative aspheric IOL`s?
  23. 23. Holladay and Piers (JRS 2002) They calculated the Modular Transfer Function (MTF) at different amounts of tilt and decentration. MTF is a mathematical/theoretical calculation of contrast (the contrast of an image relative to the contrast of the object traveling through an optical medium). This relates to quality of vision. Amount of tilt and decentration of Tecnis where the MTF (quality of vision) becomes worse than a spherical IOL: Decentration= 4mm Tilt= 7° Holladay used monochromatic light for his calculations. In 2007 Piers corrected the calculations based on the more physiologic polychromatic light we experience: 14 Decentration= .8mm Compare to 0.28 ± .16mm actual mean decentration of IOL’s with a CCC Tilt= 10° Compare to 2.6 ± 1.2° actual mean tilt of IOL’s with a CCC 15
  24. 24. 16 Ignore top dotted line (theoretical IOL with all HOA’s corrected) Solid line= Tecnis Dashed line= Spherical IOL l a w l e s s l a w l e s s Decentration Tilt PolychromaticMTF PolychromaticMTF .28 .44 2.6° 3.8° Decentration .28 ± .16 → .44mm Note: Minimal effect on MTF for most patients. 0.8 Tilt 2.6 ± 1.2° → 3.8° Note: Tilt effects MTF even less than decentration. 10° Piers’ Graph
  25. 25. 1. Spherical aberration was less with Tecnis at all pupil sizes (the bigger the pupil the larger the difference). 2. Total HOA`s were lower with Tecnis only if pupil  6.0 mm (most cataract patients’ pupils are smaller) and coma and trefoil were no different at all pupil sizes. 3. Even though spherical aberration was less, Tecnis gave no improvement in CDVA photopic with high contrast charts or mesopic low contrast charts. 4. Tecnis gave no improvement in Contrast Sensitivity photopic or mesopic. Kohnen`s team in Germany 17,18,19 A series of intraindividual studies (same patient with one eye spherical IOL and other eye Tecnis). Aspheric IOL Clinical Studies
  26. 26. 5. Were these less than expected results with Tecnis due to tilt and decentration? a) The Kohnen group measured it: Tecnis: decentration= 0.27 ± .16mm (as expected from other studies) tilt= 2.9 ± 1.5° (as expected from other studies) (Decentration and Tilt of Spherical IOL’s studied were almost exactly the same.) b) Multiple Regression Analysis showed no statistically significant correlation between decentration or tilt with the HOA’s. ie, Decentration and Tilt were not the reason why Tecnis performed worse than expected. c) This is consistent with the Piers graphs: Decentration and Tilt with a CCC are too small to significantly effect HOA’s even with negative aspheric IOL’s. Kohnen (Cont’d)
  27. 27. So why didn’t Tecnis eyes see better? They had significantly less spherical aberration and we know decentration and tilt were too small to effect that impact. Puzzling…. Possible explanations: a) Pupil size: average pupil in the study in mesopic conditions was 3.8mm. Negative spherical correcting IOL’s have a much larger effect in pupils  6.0mm. b) Interactions with other HOA’s. It is not just spherical aberration we are dealing with. Some HOA’s may interact with others in a negative or positive way. Take home message:  Factors effecting quality of vision are complex. (Marketing companies may use that to their advantage.)  Negative aspheric IOL’s are not significantly effected by decentration and tilt for most patients. 20
  28. 28. Neutral Aspheric IOL Studies Developed Several Years Later Concept 1. Do not add or subtract from the total eye spherical aberration. 2. Neutral aspheric IOL’s may not actually decrease the total eye spherical aberration but they are less effected by decentration and tilt than negative spherical IOL’s.
  29. 29.  Model Eye Study calculation of MTF with Decentration; comparing Aspheric, Neutral Aspheric, & Spherical IOL’s. Two pupil sizes and three types of IOL’s.  Verticle lines = .3 and .4mm decentration from the literature. (Mean and with one standard deviation.)  Monochromatic light (Holladay) was used. Slope should be less narrow as per Piers/ Polychromatic light. Decentration has no effect on neutral aspheric and spherical IOL..  Tecnis is more beneficial in larger pupil. 21 Modulation Tecnis Negative Aspheric Modulation Soft Port Neutral Apheric Modulation Spheric .4.4.4 .4 Eppig (JCRS 2009) 21 ModulationModulationModulation
  30. 30. Tilt has minimal effect on Tecnis even with monochromatic MTF calculations. 22
  31. 31. Swedish Multicenter Double masked study of 80 patients with Tecnis in one eye and Neutral aspheric Akreos in the other. Results (3 months post-op):  Total HOA`s less for Tecnis for 4, 5 and 6mm pupils (p <.01)  Spherical Aberration less for Tecnis for all pupils (p<.o001) Nevertheless:  No difference in CDVA mesopic and photopic with high or low contrast charts.  No difference in contrast sensitivity mesopic or photopic  Depth of field better with Acreos (p=.002) Patient Questionnaire: Subjective Visual Quality: Preferred Akreos 2X more (p<.001) Complaints of Visual disturbances Tecnis 3X more (p<.001) 23 Johansson (JCRS 2007)
  32. 32. Why was vision no better with Tecnis than Neutral Aspheric even though Tecnis had decreased HOA’s in this study? Remember: Kohnen showed vision no better with Tecnis than Spherical IOL. They suggested (1) Small mean pupil size in cataract population. (2) Interplay of HOA’s. Johansson suggests for neutral aspheric comparison 1. Better depth of field with neutral aspheric 2. Different IOL design/material
  33. 33. Things We Have Learned So Far:  Decentration and Tilt have only minor effect on Negative Spherical IOL’s and even less on Neutral Aspheric and Spherical IOL’s. Factors Effecting Quality of Vision are Complex.  Negative Aspheric IOL’s may not perform any better than Spherical IOL’s.  Neutral Aspheric IOL’s may perform better than Negative Aspheric IOL’s.  Femto Companies Suggest that better IOL Centration and Tilt Improves Vision with All IOL’s but Especially with Aspheric IOL’s, Multifocal IOL’s, and Accomodating IOL’s. Now you have the background to better evaluate such claims pro or con.
  34. 34. How Much Does 0.28 ± .16 Decentration and 2.6° ± 1.2° Tilt Effect Vision? Not much. Let`s See What the Femto Literature Has to Say…. Would even less decentration and tilt provide better UCVA and CDVA? Would even less decentration and tilt provide better contrast sensitivity and less glare and halos? Would even less decentration and tilt have more or less effect depending on whether the IOL is spherical, negative aspheric, neutral aspheric, accomodating, multifocal? Probably Not.
  35. 35. Claim of the Femtolaser Companies: Better Rhexis → Better ELP → Better Vision 4 5 4 5 Assymetric Overlap Decentered IOLCCC vs. Femto Buttons
  36. 36. Study Eyes Femto Laser Post-op Size Circularity (1=perfect) Overlap Nagy (2009) 5 pig eyes LenSx 1 wk Target 5.0 Femto better: 5.02mm vs. 5.88mm p<.001 Planker (2010)* 30 Femto 30 Phaco Catalys Intraop specimens Difference from target diameter: Femto: .027mm ± .03 CCC: .282 ± .30 p<.001 Femto: 0.95 ± .04 CCC: 0.77 ± .15 p<.001 Tackman (2011)* 49 Femto 24 CCC Lensar Intraop specimens Difference from target diameter: Femto: 0.16 ± .17mm CCC: 0.42 ± .54 p<.001 Nagy (2011)* 54 Femto 57 Phaco LenSx 1 wk Femto better p=.032 Incomplete: Femto 11% CCC 28% p=.033 Kranitz (2011)* 20 Femto 20 Phaco LenSx 1yr post-op No significant difference at 1mo and 1yr Femto better at 1mo and 1yr p<.05 Fried- man (2011)* 39 Femto 24 Phaco Catalys Intraop specimen Difference from target diameter: Femto: .029 ± .026 Phaco: .337 ± .26 p<.05 Femto: .94 ± .04 Phaco: .80 ± .15 p<.05 Reddy 2013* 56 Femto 63 Phaco Victus Inraop specimen Femto better p<.01 Femto better p<.01 Capsule centration Femto better p<.01 Femto → Rounder, Better Size and Centration → Better Overlap 24 25 26 27 28 29 30 * Human Eye Studies Names in Red= Financial Ties Green= No Financial Ties Studies: Rhexis, Size, Shape, Centration: Femto vs. Phaco
  37. 37. Kranitz (surgeon Nagy)LenSx (JRS 2011)  20 Femto Human vs. 20 Phaco Cases  Decentration of the IOL was better with Femto at 1 month and 1 year At 1 year femto .15mm ± .12 and Phaco .30mm ± .16 (p<.05) Does a better Femto Rhexis Yield Better results? 31 Even for Asheric IOL’s the Difference between 0.15mm and 0.3mm is minor. It doesn’t mean much. 0.15 0.30 This is comparing spherical IOL’s. Remember the Piers Graph for Aspherics? Piers’ Graph 16
  38. 38. Softport AO Neutral Aspheric Softport AO Spherical Kranitz (cont’d) Eppig Graph It doesn’t mean ANYTHING. Effect of Decentration on Neutral Aspheric and Spherical IOL’s.
  39. 39. Mihaltz (surgeon Nagy) LenSx (JRS 2001) 48 Femto and 51 Phaco Cases with Spherical IOL`s. 6 Month Post-op Refractive Error and HOA’s No Difference in Refractive Error:  Deviation from Intended spherical equivalent (p>.05)  Amount of Cylinder and UDVA and CDVA (p>.05) Ocular Higher Order Aberrations (4.5 virtual pupil):  No Difference in any HOA`s.  MTF (theoretical quality of vision calculated from the contrast sensitivity calculated from the HOA`s) better for Femto (p<.05) even though there was no significant difference in HOA’s between Femto and Phaco with Spherical IOL’s 32
  40. 40. Kranitz (surgeon Nagy) (JRS 2012) LenSx 20 Femto and 25 Phaco Cases with Spherical IOL`s. Measured IOL Tilt and Decentration  Femto Tilt: 2.2° ± 1.4° Phaco Tilt: 4.3° ± 2.4° Femto better (p=.001)  Femto Decentration: 0.23 ± .11mm (this is close to literature decentration of 0.28) Phaco Decentration: 0.33 ± .17mm Femto better (p=.02)  UCDVA No Difference  Deviation from Target Refraction no significant Difference CDVA Femto better at 1 month and 1 year (p-.03 and .04 respectively). (Only Study even among Red highlighted ones with this result) Kranitz Explanation for Better CDVA: Tilt Correlated With CDVA 33 Note: 4.3° tilt with Phaco IOL’s is higher than the mean tilt in the literature (.26° ± .12°). Eppig Graph Neutral Aspheric Spherical Really?
  41. 41. Filkorn (surgeon Nagy)(JRS 2012) LenSx Femto 77 and Phaco 57 Cases with Spherical IOL`s. 3 Month Post-op Refractive Error (Included -20D to +7D pre-op )  Deviation from Target spherical equivalent Femto: .12D better that Phaco (p=.04) (Only study reporting better spherical equivalent).  CDVA No Difference 34
  42. 42. Lawless 61 Femto and 29 Phaco All Restor Multifocals No Significant Difference Even In a Multifocal Where Centration Should Be Most Significant: Deviation from Target spherical equivalent: No Difference Amount of cylinder : No Difference UDVA, CDVA, UNVA: No Difference Note Deviation from Spherical Equivalent Target Femto: 0.26 ± .25 (range -.10 to 1.18) Phaco: 0.23 ± .16 (0 to .52). 35 p=.54 But….
  43. 43. Lawless (cont’d) Deviation from Targeted Spherical Equivalent Femto Phaco Standard Deviation ± .39 Range -.75 to +1.25 Standard Deviation ± .32 Range -.50 to +1.75 LESS SCATTER, SMALLER SD AND RANGE WITH PHACO
  44. 44. Abe11 100 Femto and 100 Phaco 3 week post-op  No difference between Femto and Phaco in Deviation from target spherical equivalent or CDVA 36
  45. 45. # Femto Eyes IOL Type # Phaco Eyes Deviation from Target Spherical Equiv. Cylinder UDVA CDVA UN z 48 Spherical 51 No Diff. No Diff. No Diff. No. Diff. z 20 Spherical 25 No Diff. Femto better at 1mo. & 1yr. (p=.03 & .04 respectively) rn 77 Spherical 57 Femto .12D better (p=.04) No Diff. s 61 Multifocal 29 No Diff. No Diff. No Diff. No Diff. No 100 Spherical 100 No. Diff No Diff. Femto vs. Phaco Vision only study even among the red with this result 32 33 34 35 6
  46. 46. Remember this Question? How Much Does 0.28 ± .16 Decentration and 2.6° ± 1.2° Tilt Effect Vision? Would even less decentration and tilt with Femto provide better UCVA and CDVA? Answer: No. Would it provide better contrast sensitivity and less glare and halos? No studies to date have tested this. …Why not? Why no intraindividual comparison of Femto and Phaco and measuring mesopic vision on low contrast charts (most sensitive visual acuity test for visual quality), or measuring contrast sensitivity photopic,mesopic with and without glare? Why no patient questionnaires as to which eye they like better? Would less decentration and tilt with Femto have more or less effect depending on whether the IOL is spherical, negative aspheric, neutral aspheric, accomodating, or multifocal? The studies to date have tested Femto vs. Phaco with Spherical IOL’s and a Multifocal. Answer So Far: NO
  47. 47. Rhexis Smoothness and Strength Prior to Neuhann and Gimbel`s CCC anterior capsule capsular tears occurred 100% of the time. The smooth edge of the CCC rhexis is very resistant to tearing. However making a CCC in pediatric cases is more difficult because the capsules are more elastic than in adults and the rhexis tends to run off to the periphery during manual CCC. In the 90`s new devices were tried in order to facilitate the CCC. These included vitrectors, diathermy and the Fugo “plasma blade”. 8
  48. 48. Researchers compared these techniques to CCC. It turned out that manual CCC was the Gold Standard and none of the techniques were as good. They looked at 2 things: 1)smoothness of the edge: Phaco Much Smoother than all other techniques Scanning electron micrographs (SEM’s) of the anterior capsular edge 37,38,39,40 CCC Obviously the Smoothest Vitrectorhexis CCC Can Opener Radio-Frequency Diathermy Plasma Blade
  49. 49. 2) Resistance to capsular tearing All studies showed that a CCC had a significant higher amount of stretch prior to tearing as well as higher amount of force required to tear the rhexis edge. It was assumed the rough edges with other techniques made it prone to tear the edge. The studies used 2 pins usually on calipers (each pin about 1 mm in diameter) and they opened the pins within the rhexis and measured how far the rhexis stretched prior to tearing. Some of the pins were attached to a device that could measure the force required to reach the tearing point. 38 Smoothness and Strength (Cont’d)
  50. 50. What We Learn From the Blue Dye Studies Blue Dye is used in cases when the cataract is so advanced that visualization of the anterior capsule during making of the manual CCC is difficult (poor red reflex). Staining the anterior capsule is very helpful for visualization. Several Studies have been done to see whether blue dye alters the capsule properties. It has been shown to decrease elasticity and increase stiffness of the capsule. To test whether blue dye reduces the rhexis` resistance to tearing Jaber, Werner, Mamalis at Moran Eye Center at the University of Utah did a study (with help from a grant from Alcon). Instead of narrow diameter pins stretching the rhexis they devised a testing device to more closely “simulate forces and displacements that the CCC might withstand during hydrodissection and nucleus cracking and chopping”. They used two 4.4mm shoetree shaped fixtures totaling 8.8mm attached to a force measuring device. There was no difference (with or without blue dye) in the force required to tear the edge of the rhexis even though the rhexis is stiffer with blue dye. The shoetree type of device used in this study may be relevant to how femto rhexis strength has been studied today. 41,42,43,44 45,46,47 Smoothness and Strength How to Study It (Cont’d)
  51. 51. Femto Rhexis Edge Smoothness and Strength? Nagy (JRS 2009) LenSx Pig Eyes: First in a major clinical journal that discussed the promise of Femtolaser cataract surgery. Smoothness: SEM 300X magnification. Nagy states: “the features of the laser capsulotomy were AT LEAST AS SMOOTH as those of the manual capsulorhexis”. Note: only 300X was used (all the past studies like this used 500 to 32,000X). Strength: Tested with Calipers: Femto stretched 213% and Phaco 198% (p<.001) in favor of Femto. 24 CCC edge Femto edge
  52. 52. Friedman (JCRS 2011) Catalys: Human Cadaver eyes Smoothness: He writes that the femto edge is “smooth and continuous” and is “sharpedged”. He refers to the obvious rough edge (relative to the smooth manual CCC edge) as having “microgrooves”. No magnification was given. Strength: Tested with pins attached to a force measuring device: Femto = 113 to 152 millinewtons (mN) Phaco= 65 mN p<.05 in favor of Femto. . 29 CCC edge Femto edge
  53. 53. Auffarth (JCRS 2013) Victus Pigs Eyes Smoothness: No photos shown. Only says “in some eyes the SEM images of femto looked much smoother.” Strength: Used pins. Femto=113mN and Phaco=73mN (p<.05) Femto stretched 160% and Phaco 135% (p<.05) 48
  54. 54. Femto vs. CCC The Femto Capsulotomy is beautiful looking but is it really stronger?  Smoothness: All Company studies imply or say femto edge is at least as smooth as CCC.  Strength: No Femto strength test utilized the Shoetree test used at Moran Eye Center which better simulates intraocular forces encountered during phaco.  These Company studies came out early and taught doctors that the Femto Rhexis was just as smooth and stronger than CCC. But other studies were soon to follow. Manual CCC Femto capsulotomy
  55. 55. Ostovic (surgeon Kohnen) (2013) Human Cases: Phaco CCC and LenSx (with curved glass interface) SEM up to 10,000X 49 Damaged Region Along Edge Tag Misplaced PulsesSawtooth Pattern Tag Undamaged Cells Along Edge Femto Femto Femto Femto Femto CCC
  56. 56. Mastropasqua (JCRS 2013) Human Cases; Lensar at 7mj energy, LenSx at 13.5, 14, 15mj: 1000X 50 A. Manual CCC; B-E. Femto with Increasing Laser Energy Settings
  57. 57. Abell (4 surgeons from 4 different centers)(Oph 2014) Human Cases: 10 Phaco eyes and 40 Femto eyes (Catalys, LensAr and LenSx with newest soft contact interface). SEM`s 20X to 30,000X. Note: LenSx type of curved glass interface has been shown to cause wrinkles in the cornea during creation of the rhexis; the wrinkles block the uptake of the laser pulses leading to gaps of untreated /incomplete rhexis edges. This has been improved with the soft contact interface (SoftFit) but not eliminated. Each laser platform (not just LenSx) were found to have anterior capsulotomy tags and also misplaced laser pulses (the latter consistent with eye movement during treatment). (Note pig and cadaver eye studies done in the earlier studies were able to be kept perfectly still). Able says “All 3 platforms were compromised by postage-stamp perforations that appeared rough.” 51
  58. 58. SEM 1500X LenSx anterior capsular Tag SEM only 300X Catalys anterior capsular Tag SEM 10,000X Catalys irrigular edge; arrows: misplaced laser pulses SEM 10,000x Lensar irregular edge SEM 10,000X Catalys micro-can opener structure SEM 10,000X CCC smooth SEM 1100X LenSx jagged edge SEM 1400X Lensar higher mag. of jagged edge SEM 1100X Ccc smooth Abell (Cont’d)
  59. 59. Femto Complications: Some are suction breaks, poor incisions, miosis, subconjunctival hemorrhage, and misplaced corneal laser pulses. But the most disturbing one and the one we will look closely at is Anterior CapsularTears (A.C. Tears). These can lead to posterior tears and vitreous loss and also as Andreo/Apple showed in the `90`s it can cause a relatively large decentration of the IOL.
  60. 60. Bali (Oph 2012) LenSx (with curved interface) Prospective study of the first 200 femto cases of a 6 surgeon group compared the complications to those with their previous (retrospective) 1000 regular phaco cases. They state that these complications are part of the “learning curve” associated with any new procedure and that with experience the complications can be overcome. They suggest that since anterior capsular tags were commonly present with femto that anterior capsular tears resulted. 52 Tag A.C. Tear Femto Complications (Cont’d)
  61. 61. Bali (Cont’d) First 100 femto`s then second 100 and also results of prior 1000 manual phaco. “Exclusion criteria included glaucoma, pseudoexfoliaton, small pupils (<5.0 ) or previous corneal surgery.” Note: definition of free floating cap=”required no manual detachment”. Cases Free Floating Rhexi Tags A.C. Tears (A.C.T.) A.C. Tear extended to P.C. Tear (P.C.T) Other P.C.T. Total P.C.T.’S 1-100 6 (6%) 14 (14%) 7 (7%) 101-200 29 (29%) 7 (7%) 1 (1%) Total 35 (17.5%) 21 (10.5%) 8 (4%) 4 (50% of A.C.T.’s) 3 (1.5%) 7 (3.5%) 1000 PEM 8 (0.8%) 3 (0.3%) Difference between A.C. Tears first 200 Femto (4%) and Phaco (.8%): p=<.001 But note the steep decline in A.C. Tears in the second 100 cases. The Difference between Total Femto P.C. Tears (3.5%) and Phaco (.3%): p=<.001 A.C. Tear= anterior capsular tear; P.C. Tear= posterior capsular tear
  62. 62. They state: “the geometry of the capsular tags led to extension and formation of capsular anterior capsular tears.” They recommend carefully looking for tags/notches and then completing the incomplete rhexis manually very carefully to avoid capsular tears. They also stated that better docking of the eye to the laser interface led to more free floating rhexi which required no manipulation of the rhexis manually and thus a decreased risk of capsular tear formation. Note the trend with experience of more free floating rhexi and fewer tags and less anterior capsular tears. Bali (cont’d)
  63. 63. Roberts (Oph 2013) This is a follow-up to the Bali article (LenSx still with curved interface). Same group`s next 1300 femto cases after the first 200. Note: They combine Free Floating Cap (FrFl in table) and “postage-stamp” (PS in table) configuration which they later define as “small areas of non-perforation not impacting on complete removal of the capsule button”. 53 Cases Fr Fl and PS Rhexi Tags A.C. Tears A.C.T. extending to P.C.T. Other P.C.T. Total P.C.T.’s Total A.C.T.’s & P.C.T.’s 1-200 17.5% true free floating 21 (10.5%) 8 (4%) 4 (50% of A.C.T.’s) 3 (1.5%) 7 (3.5%) 7.5% 201-1300 96% Fr. Fl. & P.S. 21 (1.6%) 4 (0.3%) 2 (50% of rt’s) 2 (.15%) 4 (0.3%) 0.62% 1000 PEM’s 8 (.8%) 3 (.3%) Femto cases 201-1300 had much fewer A.C. Tears and P.C. Tears than first 200 (p<.001) and no different than their previous 1000Phaco cases.
  64. 64. Roberts states: “Friedman et al have shown that a laser-created capsulotomy may be more than twice as strong as a capsulorhexis created manually, suggesting that normal manipulation and stretching of the capsulotomy during phacoemulsification would be unlikely to tear the capsulotomy.” And “ A.C. Tears are more likely to result from a microtag being stretched and torn during intracapsular manipulation and we recommend inspecting the edge of the laser cut capsulotomy for a capsular tag under higher magnification before phacoemulsification.” Roberts (cont’d) Roberts concludes: Better Results after the “learning curve” because: Improved laser settings and patient positioning skills  fewer incomplete capsulotomies and tags. Better Capsulotomies and better intraocular surgical technique  fewer A.C. Tears
  65. 65. Nagy ( JCRS 2014) LenSx First 100 Femto Cases (Learning Curve ) with early technology dating back to 2008 using curved interface. Exclusion: miosis, zonular weakness, active ocular disease Tags capsular Tears RT to PCT 20 (20%) 4 (4%) 0 54
  66. 66. Nagy spends a lot of time discussing technique of manual completion of the capsulotomy depending on which of 4 possible femto rhexi present themselves. “Greater surgeon experience and improved technology are associated with a significant reduction in complications.” Note: PUPIL SIZE: Nagy states that the Rhexis should be set to 1.5 mm less than the pupil or else shockwaves from the laser will hit the papillary margin thereby causing miosis and inflammation. We know that small rhexi can cause phimosis and hyperopic shifts- Cecik (Oph 1998) compared 4.0 to 6.0 rhexi and Sanders (JCRS 2006) noted if rhexis <5.5mm there is an increased chance of capsule fibrosis with posterior displacement of the IOL with hyperopic shift. According to Nagy to have a 4.5mm rhexis a pupil must dilate to 6.0. 54 1 3
  67. 67. Abell (surgeons Vote and Davies)(Oph. 2014) (Catalys) A. C. Tear Rate of Experienced Femto Surgeons 2 Experienced Femto Surgeons at 2 Different Centers Prospective study: Anterior Capsule Tear Rate 804 femto cases vs. 822 manual Phaco’s. Correlated with ultrastructural integrity of the rhexis  100% either free floating or with very delicate connections Femto → 15 Anterior Capsular Tears (1.87%) Phaco → 1 Anterior Capsular Tear (0.12%) p<.0002 → 7 with Capsular Tear extending to Posterior Capsule (47%) There was no significant difference between the 2 surgeons` results Prior anterior tear rate at the 2 centers = .06% and 0.2% which corresponds with the .12% rate in this study. 56 A.C. Tears: Phaco Better (p<.002) 15X Better
  68. 68. Unlike Bali and Roberts, Abell states: No A.C. Tears were noted while removing the capsule. “Most occurred during hydrodissection or during lens manipulations”. Only one occurred prior to hydrodissection. He states, None seemed to occur because of tags or focal attachments. Looking carefully with high magnification and a careful capsule removal technique would not have helped in these cases. They say their SEM`s showed a Femto capsulotomy creates a microscopic can-opener rhexis edge with both the LenSx, Lensar and Catalys lasers. It has “tags, skip lesions as well as regular lines of aberrant misfired pits presumably from…eye movements”. “ difference in images from before and after the latest software and hardware upgrades including the LenSx SoftFit PI for each of the laser platforms”. Abell (cont’d)
  69. 69.  Contrary to Bali, Roberts and Nagi’s recommendations, Abell states that looking carefully with high magnification and a careful capsule removal technique would not have helped in any of these cases. Equally poor capsular edge with all three lasers, and no difference in edge quality from before and after the latest software and hardware upgrades including LenSx SoftFit.
  70. 70. Chang (JCRS 2014) Lensar; Complications of first 170 Femto eyes of 3 surgeons and 180 Phaco eyes during same time period. Lensar has fluid filled interface similar to Catalys. Should have more complete rhexi than LenSx. 57 Free Floating Fr. Fl. & mild adhesions Tags A.C.T.’s P.C.T. Femto (170) 88.8% 100% 2.4% 9 (5.3%) 1 (0.56%) Phaco (180) 3 (1.7%) N/A  No financial ties to Lensar but works with AMO, Alcon, and Technolas)
  71. 71. No A.C.Tears occurred during capsule removal; all after hydrodissection and during the subsequent surgical maneuvers and prior to IOL insertion. None of the 2.4% of eyes that had tags had anterior capsule tears. He Concludes: The postage stamp effect of the microgrooves had micronotches making it easier to tear radially. He says “We suspect femto laser capsulotomy is weaker than manual CCC.” Thus similar to Abell and unlike the views of Bali,Roberts, and Nagi none of the A. C. Tears happened because of a higher incidence of incomplete flaps or inexperience at removing or completing the rhexis. Chang (Cont’d)
  72. 72. Conrad-Hengerer (surgeon: Dick) (JRS 2012) A study comparing EPT with femto and standard phaco.  57 Femto eyes. (Note: pupils  6.0) Free Floating anterior capsule=100% “Tags”= 0% “small tongue-like capsular processes”= 3 (5.3%) A.C. Tears= 0% Conrad-Hengerer (surgeon :Dick) (JCRS 11/2012) Catalys: A study comparing femto grid sizes and EPT.  160 Eyes; pupils  6.0. Free floating anterior capsule=100% “Tags”= 0% A.C. Tears= 0% Abell (surgeon: Vote) (Oph 5/13) Catalys: A Study comparing femto and phaco EPT and corneal edema. 150 femto eyes Tags= 0% Tears= 0% Mayer (surgeon: Kohnen) (AJO 2/14) LenSx (with Soft Contact Lens Pl, aka “SoftFit”) 88 femto eyes Tags= 0% Tears=0% 58 60 59 61 Addendum for A.C. Tears and Tags (Small Non-comparative Studies)
  73. 73. Phaco Power, Endothelial Cell Loss and Corneal Edema Femto vs. Phaco Effective Phaco Time (EPT)= the multiple of total phaco time and average % power used, which represents a metric for the length of phaco time if it has been used at 100% power in continuous mode. (LenSx) Adult Pig Eyes: Lenses pre-treated with Femto vs. standard divide and conquer phaco: → 51% Reduction of EPT with femto. Nagy (JRS 2009) 62
  74. 74. Takacs (surgeon, Nagy) (JRS 2012) LenSx: 38 femto cases and 38 phaco (div & conq) Central corneal thickness: Femto significantly better (p<.05) only at Day 1 (femto= 580 ± 42 and phaco= 607 ± 91. There was no significant difference at 1 week or 1 month. Central Endothelial Cell Count: No statistically significant difference between Femto and phaco. Volume stress Index (VSI): indicates corneal endothelial cell function; based on a measurement of post-op alteration of central corneal volume and central endothelial cell density) Femto significantly better at day one but not 1 week or 1 month. Question: if they are measuring corneal edema why do they not document CDVA? It is certainly easier data to present than VSI. Was there no difference even at day 1? 63
  75. 75. Conrad-Hengerer (surgeon: Dick)(JRS 2012) (Catalys) 57 phaco cases vs. 52 standard phaco cases (stop and chop) for cataract grades 2, 3, 4. Measured Effective Phaco Time (EPT) Figure 2. Diagrams showing (A) 500-m softening grid pattern compared with (B) 400/200-m segmentation and softening grid pattern. 58 60Researchers still working out best ways to soften and segment the nucleus. Femto EPT= 0.16 ± 1.21 sec. Phaco EPT = 4.07±3.14 sec. Femto → 96% reduction of EPT
  76. 76. Abell (surgeon: Vote)(Oph 2013) (Catalys) 150 femto and 51 phaco eyes (div & conq) EPT : Femto= 2.33 ± 2.28 Phaco=14.24 ± 10.90 Femto → 84% reduction of EPT (p<.0001) 30% Femto used 0 EPT; no Phaco eyes used 0 EPT; lowest Phaco EPT= 4.9 sec. Endoth Cell Loss 3 weeks post-op: Femto = -143.8+/-208.3 Femto better with p=0.022 Phaco= -224.9+/- 188.95 Central Corneal Thickness Increase on Day 1= No significant difference (Note: No One Day Post-Op CDVA’s given.) 60
  77. 77. Conrad-Hengerer (surgeon:Dick) (JCRS 2013) (Catalys) Prospective, Intraindivual , ie. Bilateral Eye Study One eye Femto, other eye Phaco (stop and chop) 73 eyes each ; Note pupils had to be  6.0mm 64.4% Femto used 0 EPT. No phaco eyes used 0 EPt; lowest phaco EPT=0.07 Endothelial Cell Loss: Femto somewhat better; no P values given. It does state “the change in less loss between the 2 groups was statistically significantly different over the whole post-operative period (p<.001). Cataract Grade Mean EPT Femto Mean EPT Phaco 2 0 0.32 ± .22 3 0.02 ± 0.03 1.17 ± 0.69 4 0.09 ± 0.15 2.5 ± 1.07 65
  78. 78. Conrad-Hengerer (cont`d) Central Corneal Thickness OBVIOUSLY no significant difference at any time, yet the Discussion states: “There was a significant reduction in central corneal thickness after femto.” If they are referring to post-op day #1, then that certainly isn’t by much. CDVA: CDVA was obtained at one day, 3-4 days, 1 wk and 3 months. No Visual Acuity results or difference in results were given. It only states that CDVA (assume for both femto and phaco) correlated with EPT at 1 day and 1 wk. However in the Discussion section it states “the visual results 1 day after surgery were significantly better” in the femto group. Note: Perhaps the authors of this study can clarify the gaps in the data/statistics reported. I do not see p values for difference in endothelial cells loss and I do not see visual acuities documented. Exam Femto Mean Phaco Mean Pre-op 553 553 1 day post-op 626 639 3-4 days 594 605 1 week 580 582 6 weeks 552 553 3 months 551 553
  79. 79. Mayer (surgeon: Kohnen) LenSx. Effective Phaco Time (EPT) and Endothelial Cell Loss (ECL); 88 eyes Femto vs. 62 eyes Phaco. Measured Endothelial Cell Count (ECC) pre-op and 1 month post-op. EPT: Femto=1.58+/-1.02 Phaco= 4.17+/-2.06 ECL: Significantly Less ECL with Femto at 1 month (p=.02) Femto better (p<.001) and better for all nuclear grades (p<.01) 61
  80. 80. EPT % Lower ECL Less CCT Thinner Nagy (‘09) 51% N/A N/A Takacs (‘12) N/A No p<.05 day 1 only Hengerer (‘12) 96% N/A N/A Abell (‘13) 84% Yes (p=.02) No Mayer (‘14) 62% Yes (p=.02) N/A  Studies agree EPT is lower with Femto  ECL is somewhat less with Phaco  CCT may or may not be slightly less on post-op day #1 with Femto EPT= Effective Phaco Power ECL= Endothelial Cell Loss CCT= Central Corneal Thickness N/A= not available Summary of Literature Results for Femto Providing Better EPT, ECL, and CCT
  81. 81. POST-OP INFLAMMATION & MACULAR EDEMA Ecsedy (surgeon: Nagy) (JRS 2011) LenSx: 20 femto and 20 phaco eyes (divide & conquer). No NSAIDS given. OCT 1 Week and 1 Month OCT Fovea= central .5mm radius Inner ring= 1.5mm radius Outer ring= 3.0mm radius Results: Change in Macular Thickness: No Results Given. They did give results for Change in Macular Thickness when adjusted for Age. 66
  82. 82. Femto Phaco 1 week .16 (20/28) ±.27 .08 (20/23) ± .16 (p>.05) 1 month .08 (20/23) ± .19 .02 (20/21) ± .06 (p>.05) MACULAR AREA 1 WEEK 1 MONTH Total Macula p>.05 p>.05 Fovea p>.05 p>.05 Inner Ring p<.001 p>.05 Outer Ring p>.05 p>.05 MEAN POST-OP CDVA (in LogMAR converted to Snellen by me) Note: CDVA with Phaco somewhat Better but p>.05 Post-op Inflammation and Macular Edema (Cont’d) Femto vs. Phaco Change in Macular Thickness (Adjusted for Age) Ecesdy (Cont’d)
  83. 83. Nagy LenSx: 12 Femto and 13 Phaco eyes. No NSAIDS. Macular OCT at 4-8 wk post-op (peak macular edema period). Note: No Pre-op Macular Thickness Obtained so No Post-op Change in Macular Thickness Given. Only Post-op Absolute Macular Thickness Reported. OCT measured not only thickness of total macula, fovea, inner and outer rings but also each retinal layer within each region. OCT Results: NO SIGNIFICANT DIFFERENCE (p>.05) for ALL LAYERS OF Total Macula, Fovea, Inner and Outer Rings EXCEPT: Femto mildly better for: 1) Outer Nuclear Layer (rods and cones) of Inner Ring (p=.04) 2)Outer Nuclear Layer (rods and cones) of Outer Ring (p=.04) CDVA RESULTS (Snellen in decimals): Femto: 1.0 ± 0 (20/22) Phaco: .95 ± .08 (20/22) (p>.05) 67
  84. 84. Abell 100 Femto Eyes vs. 76 Phaco Eyes. Post-op NSAIDS given. Measured: Aqueous Flare 1 day and 1 month post-op Macular OCT pre-op and 1 month post-op (fovea, inner and outer rings) Results: EPT: Femto less (p<.0001) Fundus Exam no difference between Femto and Phaco. Aqueous Flare: 1 week Femto Clearer (p=.009) 1 month Femto Clearer (p=.003) Slit Lamp Exam: no difference between Femto and Phaco in anterior chamber appearance. Fovea No Significant Difference Inner Ring No Significant Difference Outer Ring Femto better: p=.007 CHANGE IN MACULAR THICKNESS (1 MONTH POST-OP) FEMTO VS. PHACO 68
  85. 85. SUMMARY OF LITERATURE: FEMTO vs. PHACO INFLAMMATION AND MACULAR EDEMA Flare Total Macula Fovea Inner Ring Outer Ring CDVA Ecsedy N/A No Diff. No. Diff. Femto Better p<.001 No Diff. No Diff. Nagy N/A No Diff. No Diff Femto Better ONL p=.04 Femto Better ONL p=.04 No Diff. Abell Femto Better 1 week p=.009 1 mo. P=.003 No Diff. No Diff. No Diff. Femto Better p=.007 N/A  One study has been done and showed Flare is less with Femto  No Difference in Total Macular or Foveal Edema  Somewhat Less Edema in the Inner and Outer Macular Rings  Macular Edema Studies showed No Difference in CDVA
  86. 86. Does Femto create a prettier looking rhexis that leads to better IOL overlap? Answer: Yes. Does a prettier Femto rhexis with better overlap provide a better refractive outcome? Answer: No. Does a prettier Femto rhexis with better overlap provide better quality of vision with spherical, aspheric, neutral aspheric, or multifocal IOL’s? Answer: No. Is the Femto Rhexis edge smoother or rougher than a CCC? Answer: Rougher. Is a Femto Rhexis weaker or stronger than a CCC? Answer: Probably weaker. Is there a significant Learning Curve to Femto? Answer: Yes. Does Femto become as safe as Phaco after the Learning Curve? Answer: There is a real danger that it will not in many surgeons` hands. Does Femto minimize endothelial damage? Answer: Probably somewhat. Does Femto decrease postop corneal edema? Answer: possibly slightly on postop day 1 only Does Femto minimize macular edema? Answer: probably but not in the fovea and only in the inner and outer macular rings Is Femto superiority to Phaco an inevitability or is the basic platform flawed? Answer: The mantra is that it is improving and some day…….But perhaps the basic platform is flawed and not only is the benefit not worth the cost but also there may be NO way to improve the jagged rhexis edge despite lowering the energy settings. Is Femto a Revolution, Evolution or No Solution? Answer: you be the judge. So What Does the Current Literature Teach Us to Date?
  87. 87. Citations 1. Cekic; Oph. Surg. And Lasers; 1998; 30; p185- 2. Norby; JCRS; 2008; 34; p368- 3. Sanders; JCRS; 2006; 32; p2110- 4. Friedman; JCRS; 2011; 37; p1193- 5. Kranitz; JRS; 2011; 27; p560- 6. Neuhann; Aug. 1987; 190; p542- 7. Gimbel; JCRS; 1990; 2; p63- 8. Assia; Arch Oph; 1991; p109- 9. Assia; Oph; 1993; 100; p153- 10. Eppig; JCRS; 2009; 35; p1091- 11. Okada; Oph; 2014; 121; p763- 12. Kasper; JCRS; 2006; 32; p2023- 13. Wang; JCRS; 2003; 29; p1514- 14. Holladay; JRS; 2002; 18; p683- 15. Piers; JRS; 2007; 23; p374- 16. Piers; JRS; 2007; 23; p380- 17. Kasper; JCRS; 2006; 32; p78- 18. Kasper; JCRS; 2006; 32; p2022- 19. Baumeister; JCRS; 2009; 35; p1006- 20. Applegate; JCRS; 2003; 39; p1487- 21. Eppig; JCRS; 2009; 35; p1097- 22. Eppig; JCRS; 2009; 35; p1098- 23. Johansson; JCRS; 2007; 33; p1565- 24. Nagy; JRS; 2009; 25; p1053- 25. Tackman; JCRS; 2011; 37; p829- 26. Palanker; Sci. Trans. Med.; 2010; 2; p1- 27. Nagy 2011; JRS; 27; p564- 28. Kranitz; JRS; 2011; 27; p558- 29. Friedman; JCRS; 2011; 37; p1189- 30. Reddy; JCRS; 2013 39; p1297- 31. Kranitz; JRS; 2011; 27; p558- 32. Milhaltz; JRS; 2001; 110; p711- 33. Kranitz; JRS; 2012; 28; p259- 34. Filkorn; JRS; 2012: 28; p540- 35. Lawless; JRS; 2012; 28; p859- 36. Abell; Oph; 2013; 5; p942- 37. Krag S, JCRS; 1997; 23; p86- 38. Andreo; JCRS; 1999; 25; p534- 39. Izak A; JCRS; 2004; 30; p2606- 40. Trivedi; JCRS; 2006; 32; p1206- 41. Wollensak; JCRS; 2004; 30; p1526- 42. Dick B; JCRS; 2008; 34; p1367- 43. Jardeleza; JCRS; 2009; 35; p318- 44. Haritoglou; JCRS; 2013; 39; p1749- 45. Werner; JCRS; 2010; 36; p507- 46. Jaber; JCRS; 2012; 38; p1954- 47. Jaber; JCRS; 2012; 38; p507- 48. Auffarth; JCRS; 2013; 39; p105- 49. Ostovic; JCRS; 2013; 39; p1587- 50. Mastropasqua; JCRS; 2013; 39; p1581- 51. Abell; Oph; 2014; 121; p17- 52. Bali; Oph; 2012; 119; p891- 53. Roberts; Oph; 2013; 120; p229- 54. Nagy; JCRS; 2014; 40; p20- 55. Nagy; JCRS; 2014; 40; p24- 56. Abell; Oph; 2014; 121; p17- 57. Chang; JCRS; 2014; 40; p29- 58. Conrad-Hengerer; JRS; 2012 ; 2; p879- 59. Conrad-Hengerer; JCRS; 2012; 38; p1888- 60. Abell; Oph; 2013; 5; p942- 61. Mayer; AJO; 2014; 2; p426- 62. Nagy; JRS; 2009; 12; p1053- 63. Takacs; JRS; 2012; 6; p387- 64. Conrad-Hengerer; JCRS; 2012; 38; p1890- 65. Conrad-Hengerer; JCRS; 2013; 9; p1307- 66. Ecsedy; JRS; 2011; 27; p717- 67. Nagy; JCRS; 2012; 38; p941- 68. Abell; JCRS; 2013; 39; p1321-