submit to the journals

Femtosecond Laser-assisted Cataract Surgery

US Ophthalmic Review, 2014;7(2):82-88 DOI:


Despite improvements in surgical technique, certain aspects of manual cataract surgery are performed with limited precision. Femtosecond laser technology enables precise incisions in the cornea and minimizes manipulations and energy required to fragment and emulsify the lens, resulting in less damage to surrounding tissues compared with manual techniques. The technique also results in superior geometric precision and centration, with reported better capsule strength compared with manual capsulotomy. Femtosecond laser-assisted cataract surgery (FLACS) is particularly advantageous in difficult cases, including hypermature and white cataracts. However, it is still not known how technical advantages translate into functional benefits. Over the past 2 years, four unique laser platforms have been introduced. This article summarizes current literature relating to the efficacy and safety of FLACS and compares currently available laser platforms.
Keywords: Cataract, cornea, femtosecond laser-assisted cataract surgery, phacoemulsification
Disclosure: Michael Lawless, MBBS, FRANZCO, is a paid consultant for Alcon. Alcon has reimbursed his travel expenses and paid honoraria/speaker fees to present these scientific papers and clinical findings at various venues. Chandra Bala, PhD, MBBS (Hons), FRANZCO has no financial interest in the products mentioned. Alcon has reimbursed his travel expenses and paid honoraria/speaker fees to present these scientific papers and clinical findings at various venues. Alcon did not fund or sponsor these studies, any of the data, or clinical findings represented in the article.
Acknowledgments: Editorial assistance was provided by Katrina Mountfort, PhD, at Touch Medical Media.
Correspondence: Michael Lawless, MBBS, FRANZCO, Vision Eye Institute, 270 Victoria Avenue, Chatswood, New South Wales, 2067 Australia. E:
Support: Alcon sponsored the publication of this promotional piece and is responsible for its content along with Michael Lawless and Chandra Bala. Neither author received compensation from Alcon for their contributions to this article. The content has been independently peer reviewed and verified by the US Ophthalmic Review publication process.

Cataract surgery is one of the most commonly performed surgical procedures worldwide. Between 2000 and 2020, the number of people aged 65 or over is projected to increase from 425 million to 677 million worldwide.1 This is likely to be accompanied by a corresponding increase in the incidence of cataracts and it has been estimated that by 2020, 32 million cataract surgeries will be performed annually (see Figure 1).1

Phacoemulsification, the most commonly performed type of cataract surgery, requires manual creation of an opening in the anterior lens capsule, fragmentation and evacuation of the lens tissue with an ultrasound probe, and implantation of a plastic intraocular lens (IOL) into the remaining capsular bag. Femtosecond laser technology was approved by the US Food and Drug Administration (FDA) in 2010 for use in cataract surgery including the creation of surgical incisions in the cornea, formation of the capsulotomy, and lens fragmentation following initial clinical demonstrations of its efficacy.2 Current femtosecond laser technologies use a near infrared femtosecond laser focused to a spot size of less than 6 μm.3 Femtosecond photodisruption is achieved by generating a plasma in the tissue. This plasma, comprising free electrons and ionized molecules, then expands and causes a shock wave, cavitation, and formation of a bubble, which expands and then collapses, causing tissue separation.3 By fragmenting a cataractous lens, this technique minimizes the potential deleterious manipulations and reduces the energy required to emulsify the lens compared with non-laser-assisted phacoemulsification. Manipulations are performed within a closed chamber offering greater safety, particularly in potential cases of floppy iris syndrome.4,5

Femtosecond laser-assisted cataract surgery (FLACS) potentially offers a paradigm shift in cataract surgery. Clinical evidence in support of the use of the technique is rapidly accumulating, but the technology involves significant financial and logistical factors.6 While concerns persist regarding its cost-effectiveness,7 recent evidence suggests that, despite the initial financial outlay, FLACS represents a viable financialapproach for busy practices.8 However, unanswered questions remain,e.g. whether the anterior capsulotomy made by laser is as smooth as a manual capsulorhexes. Long-term visual and refractive outcomes are not yet known. It is also not yet known whether the technique will result in significantly lower rates of endophthalmitis, dropped nuclei, vitreous loss, and posterior capsular opacification. This article will review the literature relating to the benefits and challenges of FLACS and compare the available laser platforms.

The Benefits of Femtosecond Laser-assisted Cataract Surgery
The benefits of FLACS are described below and summarized in Table 1. However, it should be noted that studies were of varying methodological quality.

Capsulotomy Strength
The femtosecond laser creates a round opening in the anterior capsule by dissecting it with a circular laser pattern crossing the anterior capsule. This has several advantages over manually created openings, which is considered to be the most technically challenging aspect of cataract surgery.9 The capsular openings created in FLACS have increased strength and rupture force compared with those in manual capsulorhexis in cadaveric eyes.2,10–12 This may reduce the incidence of intraoperative tears to the capsular bag, a source of complications in cataract surgery. Initial data on FLACS suggest an incidence of anterior tears of 0.2 %.13 Manual cataract surgery have reported incidences between 0.79 % and 5.3 %.14–17

Capsulotomy Accuracy and Precision
Capsulotomies using FLACS are more precise than manual capsulorhexes.2,11,12,19 The unpredictable diameter observed in manual capsulorhexis may lead to an irregularly shaped capsulotomy and influence the position of the implanted IOL, which may cause a decrease in visual quality.20 Capsulotomies created during FLACS were more regularly shaped than those in manual capsulorhexes, with better centration, and better IOL/capsule overlap compared withmanual capsulorhexes.21,22

Smooth, regular edges may offer superior capsular strength and resistance to capsular tears, although the significance of capsular edge smoothness is not fully understood.23 Two recent studies used SEM to determine capsulorhexis cut quality at different energy settings and evaluated differences between laser and manual technique (see Figure 2).24,25 Both studies found the cut surface was smoother in the manual group.24,25 In FLACS, the degree of irregularity was higher with increased energy settings.25 In a study to evaluate cell death and ultrastructural morphology of capsulotomies, cut edge surfaces were found to be smoother and there was a lower level of cell death when laser pulse energy was reduced to 5 μJ—this level of smoothness was similar to the levels observed in manual capsulorhexis.26 A separate study comparing FLACS platforms and manual techniques noted a marked improvement in capsular edge smoothness with upgrades in all laser platforms (see Figure 2). Unlike previous studies the improvement in smoothness of FLACS capsulotomy edge was confirmed using objective criteria such as coefficient of variation(CoV) and gray level co-occurrence matrix (GLCM) analysis.24 The latter examined the inter-pixel changes in grayness of the scanning electron microscopy (SEM) images of the capsulotomy edge. The study noted that some FLACS platforms approached manual capsulorhexis when usingCoV and were statistically no different when examining GLCM analysis.

FLACS is also associated with less lens tilt,27,28 and fewer internal aberrations,28 which may result in improved optical quality therefore improving postoperative visual acuity and quality of vision.28 Tilting of the lens induces a considerable amount of ocular coma‐like aberrations.29 In fact, poor positioning of an IOL is one of the main indications for removal, exchange, or repositioning of a posterior chamber IOL.30 A study demonstrated a significantly better predictability of IOL power calculation than conventional phacoemulsification surgery.31 However, in this study, the results from the manual group were inferior to those published in other papers, potentially inflating the comparative outcomes.31 As surgical experience increases, it is becoming apparent that different parameters may influence visual outcomes: in a comparison of 6.0 mm versus 5.5 mm capsulotomies, vertical and horizontal tilt were significantly higher in the 6.0 mm group than in the 5.5 mm group.32 Such subtle refinements were not possible before FLACS.

  1. WHO, Blindness 2020 – control of major blinding diseases and disorders. Available at: factsheets/fs214/en/ (accessed March 18, 2014).
  2. Nagy Z, Takacs A, Filkorn T, et al., Initial clinical evaluation of an intraocular femtosecond laser in cataract surgery, J Refract Surg, 2009;25:1053–60.
  3. Donaldson KE, Braga-Mele R, Cabot F, et al., Femtosecond laser-assisted cataract surgery, J Cataract Refract Surg, 2013;39:1753–63.
  4. Martin AI, Hodge C, Lawless M, et al., Femtosecond laser cataract surgery: challenging cases, Curr Opin Ophthalmol, 2014;25:71–80.
  5. Kankariya VP, Diakonis VF, Yoo SH, et al., Management of small pupils in femtosecond-assisted cataract surgery pretreatment, Ophthalmology, 2013;120:2359–60, 60 e1.
  6. Hatch KM, Talamo JH, Laser-assisted cataract surgery: benefits and barriers, Curr Opin Ophthalmol, 2014;25:54–61.
  7. Bell RG, Vote BJ, Cost-effectiveness of femtosecond laserassisted cataract surgery versus phacoemulsification cataract surgery, Ophthalmology, 2014;121:10–6.
  8. Berdahl JP, Jensen MP, The business of refractive laser assisted cataract surgery (ReLACS), Curr Opin Ophthalmol, 2014;25:62–70.
  9. Dooley IJ, O’Brien PD, Subjective difficulty of each stage of phacoemulsification cataract surgery performed by basic surgical trainees, J Cataract Refract Surg, 2006;32:604–8.
  10. Auffarth GU, Reddy KP, Ritter R, et al., Comparison of the maximum applicable stretch force after femtosecond laserassisted and manual anterior capsulotomy, J Cataract Refract Surg, 2013;39:105–9.
  11. Friedman NJ, Palanker DV, Schuele G, et al., Femtosecond laser capsulotomy, J Cataract Refract Surg, 2011;37:1189–98.
  12. Palanker DV, Blumenkranz MS, Andersen D, et al., Femtosecond laser-assisted cataract surgery with integrated optical coherence tomography, Sci Transl Med, 2010;2:58ra85.
  13. Stodulka P, First 1000 cases of laser-assisted cataract surgery: presented at the American Academy of Ophthalmology, Subspecialty Day, November 9–10, 2012, Chicago, IL, US.
  14. Marques FF, Marques DM, Osher RH, et al., Fate of anterior capsule tears during cataract surgery, J Cataract Refract Surg, 2006;32:1638–42.
  15. Unal M, Yucel I, Sarici A, et al., Phacoemulsification with topical anesthesia: Resident experience, J Cataract Refract Surg, 2006;32:1361–5.
  16. Chang JS, Chen IN, Chan WM, et al., Initial evaluation of a femtosecond laser system in cataract surgery, J Cataract Refract Surg, 2014;40:29–36.
  17. Nagy ZZ, Takacs AI, Filkorn T, et al., Complications of femtosecond laser-assisted cataract surgery, J Cataract Refract Surg, 2014;40:20–8.
  18. Abell RG, Davies PE, Phelan D, et al., Anterior capsulotomy integrity after femtosecond laser-assisted cataract surgery, Ophthalmology, 2014;121:17–24.
  19. Tackman RN, Kuri JV, Nichamin LD, et al., Anterior capsulotomy with an ultrashort-pulse laser, J Cataract Refract Surg, 2011;37:819–24.
  20. Sanders DR, Higginbotham RW, Opatowsky IE, et al., Hyperopic shift in refraction associated with implantation of the singlepiece Collamer intraocular lens, J Cataract Refract Surg, 2006;32:2110–2.
  21. Nagy ZZ, Kranitz K, Takacs AI, et al., Comparison of intraocular lens decentration parameters after femtosecond and manual capsulotomies, J Refract Surg, 2011;27:564–9.
  22. Kranitz K, Takacs A, Mihaltz K, et al., Femtosecond laser capsulotomy and manual continuous curvilinear capsulorrhexis parameters and their effects on intraocular lens centration, J Refract Surg, 2011;27:558–63.
  23. Trivedi RH, Wilson ME, Jr, Bartholomew LR, Extensibility and scanning electron microscopy evaluation of 5 pediatric anterior capsulotomy techniques in a porcine model, J Cataract Refract Surg, 2006;32:1206–13.
  24. Bala C, Meads K, Electron microscopy of femtosecond laser capsulotomy edge: an inter-platform comparison, presented at Ranzco13, 2013.
  25. Mastropasqua L, Toto L, Calienno R, et al., Scanning electron microscopy evaluation of capsulorhexis in femtosecond laser-assisted cataract surgery, J Cataract Refract Surg, 2013;39:1581–6.
  26. Mayer WJ, Klaproth OK, Ostovic M, et al., Cell death and ultrastructural morphology of femtosecond laserassisted anterior capsulotomy, Invest Ophthalmol Vis Sci, 2014;55(2):893–8.
  27. Kranitz K, Mihaltz K, Sandor GL, et al., Intraocular lens tilt and decentration measured by Scheimpflug camera following manual or femtosecond laser-created continuous circular capsulotomy, J Refract Surg, 2012;28:259–63.
  28. Mihaltz K, Knorz MC, Alio JL, et al., Internal aberrations and optical quality after femtosecond laser anterior capsulotomy in cataract surgery, J Refract Surg, 2011;27:711–6.
  29. Oshika T, Sugita G, Miyata K, et al., Influence of tilt and decentration of scleral-sutured intraocular lens on ocular higherorder wavefront aberration, Br J Ophthalmol, 2007;91:185–8.
  30. Mamalis N, Davis B, Nilson CD, et al., Complications of foldable intraocular lenses requiring explantation or secondary intervention-2003 survey update, J Cataract Refract Surg, 2004;30:2209–18.
  31. Filkorn T, Kovacs I, Takacs A, et al., Comparison of IOL power calculation and refractive outcome after laser refractive cataract surgery with a femtosecond laser versus conventional phacoemulsification, J Refract Surg, 2012;28:540–4.
  32. Szigeti A, Kranitz K, Takacs AI, et al., Comparison of longterm visual outcome and IOL position with a single-optic accommodating IOL After 5.5- or 6.0-mm femtosecond laser capsulotomy, J Refract Surg, 2012;28:609–13.
  33. Lawless M, Bali SJ, Hodge C, et al., Outcomes of femtosecond laser cataract surgery with a diffractive multifocal intraocular lens, J Refract Surg, 2012;28:859–64.
  34. Conrad-Hengerer I, Al Juburi M, Schultz T, et al., Corneal endothelial cell loss and corneal thickness in conventional compared with femtosecond laser-assisted cataract surgery: three-month follow-up, J Cataract Refract Surg, 2013;39:1307–13.
  35. Reddy KP, Kandulla J, Auffarth GU, Effectiveness and safety of femtosecond laser-assisted lens fragmentation and anterior capsulotomy versus the manual technique in cataract surgery, J Cataract Refract Surg, 2013;39:1297–306.
  36. Abell RG, Kerr NM, Vote BJ, Toward zero effective phacoemulsification time using femtosecond laser pretreatment, Ophthalmology, 2013;120:942–8.
  37. Conrad-Hengerer I, Hengerer FH, Schultz T, et al., Effect of femtosecond laser fragmentation on effective phacoemulsification time in cataract surgery, J Refract Surg, 2012;28:879–83.
  38. Conrad-Hengerer I, Hengerer FH, Schultz T, et al., Effect of femtosecond laser fragmentation of the nucleus with different softening grid sizes on effective phaco time in cataract surgery, J Cataract Refract Surg, 2012;38:1888–94.
  39. Mayer WJ, Klaproth OK, Hengerer FH, et al., Impact of crystalline lens opacification on effective phacoemulsification time in femtosecond laser-assisted cataract surgery, Am J Ophthalmol, 2014;157:426–32 e1.
  40. Edwards KH, Frey RW, Tackmann RN, et al., Clinical outcomes following laser cataract surgery, Invest Ophthalmol Vis Sci, 2010;51:E-Abstract 5394.
  41. Roberts TV, Lawless M, Bali SJ, et al., Surgical outcomes and safety of femtosecond laser cataract surgery: a prospective study of 1500 consecutive cases, Ophthalmology, 2013;120:227–33.
  42. Takacs AI, Kovacs I, Mihaltz K, et al., Central corneal volume and endothelial cell count following femtosecond laserassisted refractive cataract surgery compared to conventional phacoemulsification, J Refract Surg, 2012;28:387–91.
  43. Masket S, Sarayba M, Ignacio T, et al., Femtosecond laserassisted cataract incisions: architectural stability and reproducibility, J Cataract Refract Surg, 2010;36:1048–9.
  44. Wang J, Sramek C, Paulus YM, et al., Retinal safety of near-infrared lasers in cataract surgery, J Biomed Opt, 2012;17:95001–1.
  45. Abell RG, Allen PL, Vote BJ, Anterior chamber flare after femtosecond laser-assisted cataract surgery, J Cataract Refract Surg, 2013;39:1321–6.
  46. Ecsedy M, Mihaltz K, Kovacs I, et al., Effect of femtosecond laser cataract surgery on the macula, J Refract Surg, 2011;27:717–22.
  47. Nagy ZZ, Ecsedy M, Kovacs I, et al., Macular morphology assessed by optical coherence tomography image segmentation after femtosecond laser-assisted and standard cataract surgery, J Cataract Refract Surg, 2012;38:941–6.
  48. Schultz T, Joachim SC, Kuehn M, et al., Changes in prostaglandin levels in patients undergoing femtosecond laser-assisted cataract surgery, J Refract Surg, 2013;29:742–7.
  49. Schultz T, Dick HB, Suction loss during femtosecond laserassisted cataract surgery, J Cataract Refract Surg, 2014;40:493–5.
  50. Bali SJ, Hodge C, Lawless M, et al., Early experience with the femtosecond laser for cataract surgery, Ophthalmology, 2012;119:891–9.
  51. Roberts TV, Sutton G, Lawless MA, et al., Capsular block syndrome associated with femtosecond laser-assisted cataract surgery, J Cataract Refract Surg, 2011;37:2068–70.
  52. Conrad-Hengerer I, Hengerer FH, Schultz T, et al., Femtosecond laser-assisted cataract surgery in eyes with a small pupil, J Cataract Refract Surg, 2013;39:1314–20.
  53. Roberts TV, Lawless M, Hodge C, Laser-assisted cataract surgery following insertion of a pupil expander for management of complex cataract and small irregular pupil, J Cataract Refract Surg, 2013;39:1921–4.
  54. Burkhard Dick H, Schultz T, Laser-assisted cataract surgery in small pupils using mechanical dilation devices, J Refract Surg, 2013;29:858–62.
  55. Chakrabarti A, Singh S, Phacoemulsification in eyes with white cataract, J Cataract Refract Surg, 2000;26:1041–7.
  56. Nagy ZZ, Kranitz K, Takacs A, et al., Intraocular femtosecond laser use in traumatic cataracts following penetrating and blunt trauma, J Refract Surg, 2012;28:151–3.
  57. Conrad-Hengerer I, Hengerer FH, Joachim SC, et al., Femtosecond laser-assisted cataract surgery in intumescent white cataracts, J Cataract Refract Surg, 2014;40:44–50.
  58. Talamo JH, Gooding P, Angeley D, et al., Optical patient interface in femtosecond laser-assisted cataract surgery: contact corneal applanation versus liquid immersion, J Cataract Refract Surg, 2013;39:501–10.
  59. Kerr NM, Abell RG, Vote BJ, Toh T, Intraocular pressure during femtosecond laser pretreatment of cataract, J Cataract Refract Surg, 2013;39:339–42.
Keywords: Cataract, cornea, femtosecond laser-assisted cataract surgery, phacoemulsification