1. The femtosecond laser was approved in 2010 for cataract surgery.
2. OptiMedica (Santa Clara, CA), LenSx (recently acquired by Alcon, Fort Worth, TX), and LensAR (Winter Park, FL) are devoting themselves to this wonderful work.
3. In the 1970s, Krasnov utilized a laser modality for phacopuncture in cataract surgery .
4. Advanced intraocular lens (like multifocal, aspherical IOL, accommodative lens, toric lens) and increasing of patient expectations for near-perfect vision are the driving force to need a more accuracy and prcision in cataract surgery.
5. Mechanism of Femtosecond lasers in ophthalmology: Photodisruption with cavitation, and bubble formation, exactly in an accuracy of 1 um.
6. Steps in femtosecond laser-assisted cataract surgery:
Similar to femtosecond assisited Lasik, but require pupillary dilatation. Topical anesthesia, docking system, increasing IOP, anterior segment imaging system using FD-OCT(Optimedica) or Scheimpflug imaging technology(LensAR), casulotomy, fragmentation, incision planning(includ limbal-relaxing incisions if need). The last procedure is to penetrate the posterior corneal surface with a microsurgical blade, and then followed by standard phacoemulsification.
7. Advantages:
more stroger square corneal incision resistant to leakage, more smoother and regularer edges resistant to capsular tears (12 months postoperation didn’t show difference to mannual capsulorhexis), more safer to coreal injury and less complications.
Warning: a shift of 1 mm in IOL position-which can stem from an inappropriately sized capsulotomy-can lead to approximately 1.25 D change in refractive error(reported by Norrby).
8. Studies
Femtosecond laser-assisted corneal incision: Masket et al(2010), Palanker et al(2010). However, this femtosecond laser assisted corneal incision didnot show in decrease rate of postoperative endophthalmitis.
Femtosecond laser-assisted capsulorhexis: Nagy et al(2011), Friedman NJ(2011), Palanker DV(2010),Kránitz et al.(2011),Nagy Z(2009).
Femtosecond laser-assisted phacofragmentation: Fishkind W(2010), Koch D(2010), Nagy et al(2009), Palanker DV(2010), Palanker et al(2010), Uy HS. Illinois, USA: 2010.
9. Outcomes and complications
Palanker et al(50 patients)’s study showed: 80% of patients showed small petechial conjunctival hemorrhages and vasodilatation in a ring pattern around the area of the suction contact lens. 38% of laser patients and 70% of traditional cataract surgery patients experienced corneal edema. Best corrected visual acuity (BCVA) showed a gain of 4.3±3.8 lines in the laser group (n=29) and a gain of 3.5±2.1 lines in the traditional group (n=30). No damage in rabit experiment.
Slade SG. Illinois, USA: 2010: The author showed less induced coma and astigmatism, manipulation, and phacoemulsification time.Edwards KH(2010): no significant difference in the outcomes of BCVA, IOP, or corneal thickness between the two groups. No major complications.
