REVIEW

A Review of Laser-Assisted Versus TraditionalPhacoemulsification Cataract Surgery

H. Burkhard Dick . Tim Schultz

Received: December 12, 2016 / Published online: February 10, 2017� The Author(s) 2017. This article is published with open access at Springerlink.com

ABSTRACT

The use of femtosecond laser surgery improvesthe precision and reproducibility of cornealincisions and the capsular opening; it alsoreduces the amount of ultrasound energyrequired for lens nucleus work-up. The rate ofcomplications reported so far appears to be low.There are a number of contraindications such asa history of cornea and/or glaucoma surgeryand certain anatomical features like deep-seteyes, kyphosis, tremor, and obesity. Visualrecovery and refractive results of both tech-niques are excellent. Comparing laser cataractsurgery (LCS) with manual cataract surgery(conventional phacoemulsification) based onmeta-analysis currently reveals slight differ-ences in refractive and visual outcome. Bothmethods are extremely successful and safe. LCSis a technique still on the rise, with its fullpotential not yet tapped.

Keywords: Capsulotomy; Cataract; Capsu-lorhexis; Effective phaco time; Endothelial cell

count; Femtosecond laser; Intraocular lens; Lasercataract surgery; Manual phacoemulsification;Ultrasound; Prostaglandin

INTRODUCTION

In most industrialized nations, cataract surgeryis by far the most frequently performed surgicalintervention, surpassing in numbers othercommon procedures from all the different sur-gical subspecialties such as hip or kneereplacement, appendectomy, tonsillectomy,and cholecystectomy. The advent of minimalincisions, foldable intraocular lenses (IOL), andthe application of ultrasound energy for thefragmentation of the lens, i.e., for phacoemul-sification as introduced by Charles Kelman inthe 1970s, has made cataract surgery efficientand safe. It can be argued that modern cataractsurgery—which is always refractive surgery,striving to provide the patient with an optimalvisual acuity without requiring additional cor-rection—is an intervention that in many casesnot only restores an organ’s function but alsocan render it better than it has been for almost alifetime. This happens, for instance, when apatient myopic since childhood or adolescencebecomes emmetropic after implantation of theappropriate IOL.

New methods in medicine often face intenseand, arguably, not always fair scrutiny—eventhe most beneficial inventions like smallpox

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H. B. Dick (&) � T. SchultzUniversity Eye Hospital, In der Schornau 23–25,44892 Bochum, Germanye-mail: burkhard.dick@kk-bochum.de

Ophthalmol Ther (2017) 6:7–18

DOI 10.1007/s40123-017-0080-z

immunization, anesthesia, and antisepsis had toovercome initial objections. It is even more of achallenge when an innovation has to competewith an established method like phacoemulsi-fication cataract surgery whose efficacy andsafety are well established. In cataract andrefractive surgery, the expectations are everincreasing with many elderly people leading anactive lifestyle and being well informed aboutthe possibilities in modern ophthalmology.Superb postoperative visual function is oftenexpected, sometimes even taken for granted.For many patients, a cataract operation shouldresult in visual acuity of 20/20 without glassesfor distance vision. With the advent of multi-focal and accommodating IOLs, the highestvisual comfort for near, intermediate, and dis-tance vision is advertised. We recommend usingexactly that term—laser cataract surgery (LCS)—to describe the new method since the laser is acentral element in the procedure and not justan assisting device as intimated in the termfemtosecond laser-assisted cataract surgery(FLACS) [1].

Since the introduction of the femtosecondlaser into cataract surgery by Zoltan Nagy in2009 [2], a number of comparisons of the newtechnique with conventional (manual) pha-coemulsification have been published, based onan ever-increasing number of cases. The assess-ment by the pioneering surgeon Nagy that‘‘femtolaser treatment of the crystalline lensincreases safety, efficacy, and predictability ofthe surgery’’ [3] has now been tested numeroustimes. Recently some major meta-analyses havebeen published by Popovic et al. [4] and by Dayet al. [5] that provide valuable overviews—though some questions still remain unansweredand will require further research and clinicalexperience.

There is probably a differing perception ofthe merits of each of these two techniques,depending on which one the individual cataractsurgeon prefers. It is the aim of this review toprovide the reader with samples of the datafrom the large amount of literature on somecrucial aspects of LCS in comparison to con-ventional phacoemulsification cataract surgery.Some of this information stems from smallstudies and/or is based on our own experience;

other results are taken from larger trials andfrom meta-analyses.

This review is based on previously conductedstudies and does not involve any new studies ofhuman or animal subjects performed by theauthor.

EFFICACY

Capsulotomy

Creating a precise, safe, and reproducible cap-sulotomy is a prerequisite for success in cataractsurgery and for IOL implantation. Compared tomanual capsulorhexis [6], the laser has beenshown to create a particularly well-shaped andreproducible capsulotomy geometry and circu-larity [7]. Numerous studies confirmed thatthese non-invasively created circular capsularopenings contribute to an improved IOL–cap-sule overlap (Fig. 1). Capsulotomies performedby the femtosecond laser reduce the probabilityof IOL decentration and tilt [8].

Regarding the strength of the capsulotomies,Scott et al. reported radial capsular tears in 38eyes out of a cohort of 8684 cases. That amountsto a rate of 0.43% [9] compared to 2.32% formanual phacoemulsification cataract surgeryreported in the literature [10]. Roberts et al.

Fig. 1 Round, circular, centered capsulotomy in LCS witha 360� overlap on the IOL optic (intraoperative viewthrough the OR microscope)

8 Ophthalmol Ther (2017) 6:7–18

reported an even smaller rate of anterior capsuletears of 0.21% in a cohort of 3355 eyes [11]. In alarge study comparing 1852 eyes that under-went LCS and 2228 eyes in the phaco group,Abell et al. found that anterior capsule tearsoccurred in 1.84% of eyes in the study groupand 0.22% of eyes in the control group(P\0.0001). Anterior capsulotomy tags occur-red in 1.62% of study group eyes. The authorsclaimed that the higher incidence of anteriorcapsule tears was not related to the learningcurve. They concluded that in general, signifi-cant intraoperative complications that are likelyto affect refractive outcomes and patient satis-faction were low in both groups [12].

There is evidence that the femtosecond lasercan successfully be employed when a manualcapsulorhexis turns out to be far less than per-fect. Manual capsulorhexis, particularly whenperformed by a surgeon still climbing theirlearning curve, can be too small which mightlead to capsule shrinkage that in turn can causeIOL decentration and decreased vision. In fivecases that we have described, it was possible toenlarge a markedly smaller capsulotomy byusing the femtosecond laser with a 360� overlapwithout complications. With the laser plat-form’s 3-D spectral-domain OCT, it was possiblein all cases to identify and target the anteriorcapsule. This technique has potential to be usedroutinely in intended as well as unintendedcases with a smaller capsule opening [13].

Another rescue mission performed with thefemtosecond laser has been described in anumber of cases with capsular contraction syn-drome—‘‘capsular phimosis’’—by Gerten et al.This technique may offer advantages over theexisting treatment methods, neodymium:YAGlaser capsulotomy and manual extension of thecapsulorhexis, though tissue bridges mightremain [14].

Refractive Outcome

The earlier the capsular bag diameter stabilizesthe better for a more predictable effective lensposition, IOL power calculations, and refractiveoutcomes. Measuring capsular bag shrinkage in53 eyes that underwent LCS and in 53 fellow

eyes that underwent manual phacoemulsifica-tion, the LCS group had significantly less cap-sular bag shrinkage than the standard group at1, 2, and 3 months, with a mean difference of0.33 ± 0.25 mm at 3 months [15].

A number of studies have compared therefractive outcome of laser and conventionalprocedures—in many cases an aspect which is ofprime importance for the patient. Roberts et al.,for instance, found no significant difference invisual outcomes in a prospective study of 113LCS procedures versus 105 conventional cases.The absolute mean difference from intendedcorrection was 0.29 ± 0.25 D for the LCS groupand 0.31 ± 0.24 D for the standard group(P = 0.5). More than 90% of patients in bothgroups achieved 20/40 uncorrected distancevisual acuity at 3 months [16]. Mihaltz et al.compared the ocular and internal aberrationsafter femtosecond laser anterior capsulotomyand continuous curvilinear capsulorhexis incataract surgery. They found no differencesbetween the LCS and manual groups in post-operative sphere (-0.60 ± 1.50 vs-0.50 ± 1.40 D), postoperative cylinder(1.30 ± 1.01 vs 1.10 ± 1.10 D), uncorrected dis-tance visual acuity (0.86 ± 0.15 vs 0.88 ± 0.08),or corrected distance visual acuity (0.97 ± 0.08vs 0.97 ± 0.06). However, they noted that thelaser group had significantly lower values ofhigher-order aberrations, namely intraocularvertical tilt (vertical deviation in the directionof the beam of light; -0.05 ± 0.36 vs0.27 ± 0.57), coma (variation in magnificationover the entrance pupil; -0.003 ± 0.11 vs.0.1 ± 0.15), significantly higher Strehl ratios(ratio of peak diffraction intensities of an aber-rated versus perfect wavefront; 0.02 ± 0.02 vs.0.01 ± 0.01), and modulation transfer functionvalues at all measured cycles per degree, com-pared to the manual capsulorhexis group [17].

In a prospective, randomized cohort studywith the aim to analyze postoperative manifestrefraction and the deviation from the targetrefraction, 100 eyes of 100 patients were treatedwith femtosecond laser cataract surgery; thefellow 100 eyes had conventional phacoemul-sification. Six months postoperatively, 196 eyeswere included and analyzed. At 6 months, 90eyes (92%) in the femtosecond laser group and

Ophthalmol Ther (2017) 6:7–18 9

70 eyes (71%) in the conventional group werewithin ±0.50 D of the target refractive outcomeand 98 eyes (100%) in both groups werewithin ±1.00 D. Conrad-Hengerer et al. con-cluded that femtosecond laser cataract surgeryis a safe and precise procedure but enhancesvisual outcomes only minimally. Manuallyperformed cataract removal in standard cases inthe hands of an experienced surgeon can obvi-ously provide a similar level of refractive resultsafter 6 months. However, there was an advan-tage in favor of the laser in the early postoper-ative visual recovery period (until 1 week) overconventional surgery. Furthermore, the refrac-tive result stabilized earlier in the femtosecondlaser-assisted group [18].

Visual Acuity

A number of studies have evaluated best-cor-rected visual acuity (BCVA) and uncorrecteddistance visual acuity (UDVA) after both meth-ods. Generally speaking, the differences in thisoutcome following LCS or manual phacoemul-sification were minimal to non-existent. Mas-tropasqua et al. for instance found a UDVA of0.35 logMAR in the laser group and of0.28 logMAR in the standard phacoemulsifica-tion group 1 month postoperatively. Six monthsafter surgery, the UDVA was 0.13 and0.08 logMAR in these two respective groups [19].Kranitz et al., using Snellen visual acuity, found aUDVA of 0.59 (SD 0.23) and 0.51 (SD 0.29) in theLCS and the standard phacoemulsificationcohorts, respectively. At 1 month, UDVA valueswere 0.69 (SD 0.19) and 0.61 (SD 0.28) inlaser-operated eyes and eyes after conventionalcataract surgery, respectively; after 1 year, therespective values were 0.63 (SD 0.23) and 0.60(SD 0.25). They found no statistically significantdifference between arms at any time point [20].

Popovic et al. did an extensive literatureresearch that included 14,567 eyes from 15randomized controlled trials and 22 observa-tional cohort studies. Not entirely unexpectedgiven the high standard of the well-establishedconventional procedure, no statistically signifi-cant difference was detected between LCS andmanual phacoemulsification in uncorrected

distance visual acuity (weighted mean differ-ence [WMD] -0.02; 95% CI -0.04 to 0.01; P 1/40.19), corrected distance visual acuity (WMD-0.01; 95% CI -0.02 to 0.01; P = 0.26), andmean absolute error (WMD -0.02; 95% CI-0.07 to 0.04; P = 0.57). The same applied tototal surgery time. Effective phacoemulsifica-tion time (EPT) was significantly lower in lasercataract surgery in eight out of eight analyzedstudies [4].

SAFETY

Corneal Incisions

In our report on the histology of corneal fem-tosecond laser incisions we could demonstratethe extremely precise positioning of intrastro-mal incisions (Figs. 2 and 3), the minimal tissuebridges left, and the absence of inflammatorycells, pointing to a higher safety standard thanpossible with a manual incision [21].

Takacs et al. demonstrated in a prospective,randomized study less corneal swelling andendothelial cell damage in patients undergoingLCS compared to a conventional phacoemulsi-fication technique [22]. Alio et al. compared thestability of clear cornea incisions done by thefemtosecond laser and found that the actual

Fig. 2 Preoperative planning of the intrastromal arcuatecorneal incision in the femtosecond laser machine

10 Ophthalmol Ther (2017) 6:7–18

length, chord length, and surface angle for theprimary incision and the length and surfaceangle for the secondary incisions were stable at1 day and 1 month following the surgery [23].

Endothelial Cell Count and UltrasoundExposure

The application of ultrasound energy within theanatomically rather confined structures of theanterior segment is an essential step in pha-coemulsification. It is a valuable tool, but notwithout its risks. High ultrasound power andlong ultrasound time (effective phacoemulsifi-cation time, EPT) are probably importantintraoperative factors leading to endothelial cellloss, sometimes excessive loss, after pha-coemulsification in healthy eyes with no pre-vious risk factors, such as a history ofintraocular surgery, pseudoexfoliation, or cor-neal dystrophy [24]. Ultrasound energy has alsobeen implicated in the pathogenesis of cystoidmacular edema [25]. With increasing experiencewith femtosecond laser technology the amountof ultrasound energy usually decreases (Fig. 4).

A study from Australia by Abell et al. com-pared 150 patients undergoing femtosecondlaser treatment and 51 patients undergoingconventional phacoemulsification. The study

found a mean EPT reduction in the laser groupby 83.6% with 30% of patients in this groupachieving zero EPT [26]. After femtosecondlaser-assisted cataract surgery was introduced inour clinic, the necessity for ultrasound applica-tion gradually declined with our growingexperience with the femtosecond laser treat-ment. While phacoemulsification was still nee-ded in 59% of patients (from the 200th to the400th patient) after the introduction of LCS, inthe group comprising the 700th to the 900thpatient, only 38% required phacoemulsificationfor lens fragmentation. After further climbing ofthe learning curve, phacoemulsification wasrequired in only 9% of patients—number 1200to number 1400. All 18 eyes that requiredultrasound energy had a grade 4 (LOCS III)cataract and the median EPT was 0.4 s. Morethan 90% of our surgeries are performed with‘‘zero phaco’’. In grade 2 cataracts, there is cur-rently no ultrasound application in 100% ofcases [27].

A catastrophic cell loss leading to a density of500 or less cells per mm2 will result in cornealdecompensation which in many cases requires akeratoplasty, either penetrating or lamellar. It is

Fig. 3 Intraoperative position check of the intrastromalincision using 3-D SD LIVE OCT (after docking). Achange of length, depth, arc, centration method, andposition is still possible Fig. 4 Full fragmentation of the advanced cataractous lens

using a two main cut pattern (with multiple repetitionsherein) in LCS. Cavitation gas bubbles appear at the endof the lasing

Ophthalmol Ther (2017) 6:7–18 11

well established that ultrasound applicationduring phacoemulsification can lead toendothelial cell damage in cataract surgery dueto mechanical trauma from sonic waves andfrom thermal injury [24]. While improvementsof phacoemulsification technology have madethe application less perilous for the endothe-lium, Mencucci et al. nevertheless reported anot insignificant endothelial cell loss between4% and 25% [28].

There is now sufficient evidence to declarelaser cataract surgery the method less traumaticto the corneal endothelium. In a prospective,randomized study of 150 eyes, Conrad-Hen-gerer et al. reported that the mean endothelialcell loss was 7.9% ± 7.8% 1 week postopera-tively and 8.1% ± 8.1% 3 months postopera-tively in the LCS group and 12.1% ± 7.3% and13.7% ± 8.4%, respectively, in the controlgroup (P\0.001). They found a positive corre-lation between endothelial cell loss at the 3-month postoperative visit (r = 0.43) and theEPT. In the laser group 64.4% of eyes had zeroEPT. The femtosecond laser can be consideredparticularly beneficial in eyes with low preop-erative endothelial cell counts, such as in casesof cornea guttata and Fuchs dystrophy [29]. Thedifferences were less pronounced in a study byKrarup et al. with endothelial cell loss at3 months postoperatively of 11.4% (after lasertreatment) and of 13.9% following conven-tional phacoemulsification [30]. Schargus et al.demonstrated that femtosecond laser treatmentallows the cataract surgeon to perform pha-coemulsification and intraocular lens implan-tation without the use of ophthalmicviscosurgical device (OVD) at no additional riskto the corneal endothelium [31].

In the aforementioned meta-analysis byPopovic et al., the analysis of safety parametersrevealed that there were no statistically signifi-cant differences in the incidence of overallcomplications between LCS and manual catar-act surgery; however, posterior capsular tearswere significantly more common in laser catar-act surgery (RR 3.73). The authors add: ‘‘Theremay be certain clinical scenarios, such as casesin which a manual capsulorhexis is harder toperform (e.g., subluxated lens), in which LCSmay have specific advantages. Furthermore,

there may be applications and modifications ofthe IOL technology in the future that may favorlaser over manual cataract surgery. Because ofthe continual evolution of the femtosecondlaser technology, it is likely that there will becontinued head-to-head comparisons betweenthese two techniques’’ [4].

Prostaglandin Release

Soon after the introduction of the femtosecondlaser into cataract surgery, first reports of intra-operative miosis in some patients surfaced [32].The cause of this problem—and it can be aproblem since small pupils can increase thedifficulty of the surgery and lead to highercomplication rates during lens removal [33]—was soon identified: it is the release of pros-taglandins by the laser treatment.

It has been well known for some time thatprostaglandins appear in the aqueous humorfollowing different mechanical or thermalstimuli. The principal source for prostaglandinsin the eye is the non-pigmented epithelial layerof the ciliary body. So we collected aqueoushumor from 113 patients who during cataractsurgery either had just undergone femtosecondlaser treatment or—in the control group of 107eyes—before commencing conventional pha-coemulsification. A large difference was foundbetween the two groups. In the femtosecondlaser group the average level of prostaglandin E2in one part of the study was 182 pg/ml—morethan tenfold the concentration of PGE2 in thecontrol group, which was 17.3 pg/ml [34].

The easiest prophylaxis of an excessiveprostaglandin release might be speed. If thepatient is swiveled around on his treatment bedfrom under the laser platform to the adjoiningposition under the operating microscopeimmediately, the prostaglandins released bycapsulotomy hardly have the time to exert theireffect on the muscularis sphincter pupillae. Thisis one argument—besides, for instance, hygie-nic considerations—in favor of performing lasertreatment and the following steps such as lensremoval and IOL in the same operating roominstead of doing the former in a separate ‘‘lasersuite’’ [35].

12 Ophthalmol Ther (2017) 6:7–18

There is, however, beyond the speed factor aproven pharmacological prophylaxis: adminis-tering non-steroidal anti-inflammatory drugs(NSAID), one eye drop three times on the day ofsurgery before initiating treatment reliably pre-vents miosis. NSAID or steroidal pretreatmentmight be advisable to decrease a possible risk ofinflammation and hence intraoperative miosis.It is a highly effective precaution: of the last 500eyes that received these drugs in our clinic,none became miotic [34].

Inflammation

The prostaglandin release can trigger an alter-ation of the blood–aqueous barrier and lead topostoperative inflammation that can clinicallymanifest as a mild iritis and with increased cellsand protein in the anterior chamber. The lattereffect causes a flare which can be quantified asan indicator of inflammation by laser flarephotometry. Abell et al. demonstrated thatpostoperative aqueous flare was significantlygreater in eyes that had undergone manualcataract surgery at 1 day and at 4 weeks post-operatively than in eyes after LCS [36]. Con-rad-Hengerer et al. published similar results:when comparing 104 eyes that underwent lasercataract surgery with 104 fellow eyes which hadmanual phacoemulsification, laser flare pho-tometry showed higher levels in the standardgroup at the first postoperative visit 2 h aftersurgery compared with the laser group. In thesame study, retinal thickness was measured byspectral-domain optical coherence tomography.No significant differences could be detected,indicating that LCS did not obviously influencethe incidence of postoperative macular edema[29]. A different tendency was reported by agroup from Australia, though, with seven casesof macular edema out of 833 eyes (0.8%) oper-ated on with the laser vs. one eye in a group of458 conventionally operated cases (0.1%) [37].

LCS IN CHALLENGING CASES

The safety and efficacy of LCS (Fig. 5) has beendemonstrated in a number of special cases. Theaccuracy and reproducibility of the laser

capsulotomy are particularly valuable in pedi-atric patients. A posterior capsulotomy of theright size is crucial up to the age of 6 years toprevent posterior capsule opacification (PCO)and for the implantation of an IOL that is fix-ated in the capsular bag. Because of the infantlens capsule’s high elasticity, manual anteriorand posterior capsulorhexes are challenging toperform and frequently lead to an oversizedcapsule opening. Capsulotomy performed bythe laser has been proven safe and effective,with tissue bridges remaining in 6 eyes out of 22successful capsulotomies [38]. The age-depen-dent deviation from the capsulotomy’s targetdiameter which was observed in the initialoperations of children with congenital cataractcan be overcome by the Bochum formula.Applying this formula has become crucial inachieving a precalculated diameter and allow-ing precise adjustment of the posterior capsu-lotomy to the anterior capsulotomy [39].

Brunescent cataracts usually require anincreased phacoemulsification time and are athigher risk for thermal and mechanical injuryto the cornea and corneal edema. In a study on240 eyes, LCS was more effective than pha-coemulsification in fragmenting the advancedcataract in so far as requiring far less EPT. Ineyes with LOCS III grade 3 cataracts, EPT ranged

Fig. 5 Screenshot of the planning in LCS (with mainincision, two sideports, two arcuate incisions, capsulotomy,and lens fragmentation)

Ophthalmol Ther (2017) 6:7–18 13

from 0.46 to 3.10 s (mean 1.38) in the phacogroup while it was zero in the laser group. Ineyes with grade 4 brunescent cataracts, EPT was2.12 to 19.29 s (mean 6.85) in the phaco groupand 0 to 6.75 s (mean 1.35) in the laser group[40].

A comparable situation exists with intumes-cent cataracts which usually pose a challenge tothe surgeon since they tend to have increasedintralenticular pressure due to liquefaction ofthe cortex. To release this pressure, a mini-cap-sulotomy (Fig. 6) technique where a smallercapsulotomy is initially performed to release theintralenticular pressure followed by re-dockingon the laser machine and a second larger cap-sulotomy has been developed [41], which seemsto render operating on white cataracts safe—and probably more so than manual capsu-lorhexis with its potential for complications[42].

CONTRAINDICATIONS TO LCS

A number of patients will not be able toundergo laser cataract surgery because of someanatomical features. Deep-set eyes, a prominentnose, and prominent eyebrows may rendercontact between the globe and the laser’sinterface impossible. Heavily overweight

patients may not fit onto the treatment bed andlowering the interface will in cases of obesitynot result in coupling to the cornea’s surface.Skeletal anomalies like a pronounced kyphosismight prevent patients from lying down prop-erly under the treatment unit. A tremor andrestless legs syndrome are also contraindica-tions. LCS should not be performed in eyes withprevious glaucoma or cornea surgery. Cornealscars are mentioned as contraindications;depending on their extent, experienced sur-geons might consider this an obstacle that canbe overcome.

DISCUSSION

Femtosecond laser treatment shows great pro-mise in increasing the accuracy and precision ofthe cuts compared to the manual procedure.Favorable refractive and functional outcomesand good safety profiles have been reported.The Cochrane analysis comparing LCS withstandard phacoemulsification cataract surgeryconcluded that in the evaluated studies therewas a small difference in postoperative refrac-tion prediction error (mean absolute error) infavor of laser-assisted surgery but the confi-dence intervals for this estimate included aclinically insignificant effect. The general con-clusion of the analysis was that evidence fromthe 16 randomized controlled trials (RCTs)included in the Cochrane review could notdetermine the equivalence or superiority oflaser-assisted cataract surgery compared tostandard manual phacoemulsification for thechosen outcomes because of the low to very lowcertainty of the evidence available from thesestudies [5].

LCS provides new options in the treatmentof advanced pathologies. Furthermore, there areevolving techniques to reduce the likelihood ofpostoperative capsule opacification as recentlydescribed by Gregory Kramer, Liliana Werner,and Nick Mamalis [43] that certainly can beemployed in laser-assisted operations as well asin manual cataract surgery. Preventing thismost common complication after cataract sur-gery to a certain degree is probably also possible

Fig. 6 Mini-capsulotomy on intraoperative laser systemscreen view demonstrating its centration, position, and size

14 Ophthalmol Ther (2017) 6:7–18

by employing the laser to perform a primaryposterior capsulotomy (Fig. 7) [44].

The two major meta-analyses published veryrecently give proof that both techniques, LCSand manual phacoemulsification, are highlyeffective and safe with differences in someparameters minor or non-existent. Besides thepublication by Popovic et al. that was men-tioned earlier, the Cochrane review by Day et al.found little evidence of any important differ-ence in postoperative visual acuity betweenlaser-assisted and standard phacoemulsificationarms. There was a small advantage for laser-as-sisted cataract surgery at 6 months in correcteddistance visual acuity (CDVA). The mean dif-ference (MD) was -0.03 logMAR and was con-sidered clinically insignificant. None of theanalyzed trials were powered to investigate fordifferences in complication rates [5].

With growing experience, LCS has—likemanual phacoemulsification—become a proce-dure that can be used in most of the patients.Patients representing challenging cases likethose with Marfan syndrome [45], intumescentcataract as well as pediatric cases do not have tobe turned away although these interventionsrequire a high degree of surgical skills.

There are a number of contraindications,however, and some patients are without doubtbetter served by manual cataract surgery.

A field where LCS lags behind conventionalphacoemulsification is the economic side of thisfrequent intervention. Abell et al., using a

computer-based econometric modeling, con-cluded in 2014 that laser cataract surgery at thetime of publication is not cost-effective com-pared to phacoemulsification [46]. Thisapproach has, however, some weaknesses anddoes not take into account, for instance, coststhat arise from complications like cornealdecompensation and the expenses for glassesetc. to correct remaining refractive errors aftercataract surgery. Like with any new technology,it is likely that the price of laser cataract surgerywill decrease over time.

LCS has a large clinical potential that has notyet been fully tapped with new applications likeintraoperative biomorphometry on the horizon.

CONCLUSION

According to a number of studies femtosecondlaser surgery has the potential to improve theprecision and reproducibility of corneal inci-sions and the capsular opening. It has beendocumented that LCS reduces the amount ofultrasound energy required for lens removal.The reported rate of complications is low andthere are limited contraindications. Visualrecovery and refractive results are promising.There are, however, a couple of challenges fac-ing wider acceptance of the femtosecond laserin cataract surgery. The economic aspect is ofimportance. The higher costs are a barrier towider acceptance by surgeons and clinical cen-ters. However, to increase acceptance the nextgeneration of the lasers systems needs to besmaller, more mobile, and less dependent on anarrowly defined room temperature than thecurrent ones. LCS is still a young technology inprogress and surgeons can offer their patientstwo safe and efficient techniques in operatingcataracts: LCS and—not ‘‘versus’’, not ‘‘or’’—phacoemulsification.

ACKNOWLEDGEMENTS

No funding or sponsorship was received for thisstudy or publication of this article. All namedauthors meet the International Committee ofMedical Journal Editors (ICMJE) criteria for

Fig. 7 Primary posterior laser-assisted capsulotomy withthe IOL in the capsular bag and some cavitation bubbles(intraoperative view through the OR microscope at theend of the surgery)

Ophthalmol Ther (2017) 6:7–18 15

authorship for this manuscript, take responsi-bility for the integrity of the work as a whole,and have given final approval for the version tobe published. This review is based on a presen-tation given at the ESCRS 2016 winter confer-ence in Copenhagen titled ‘‘Laser assisted vs.traditional phaco cataract surgery’’.

Disclosures. H. B. Dick and T. Schultz havenothing to disclose.

Compliance with Ethics Guidelines. Thisarticle is based on previously conducted studiesand does not involve any new studies of humanor animal subjects performed by any of theauthors.

Open Access. This article is distributedunder the terms of the Creative CommonsAttribution-NonCommercial 4.0 InternationalLicense (http://creativecommons.org/licenses/by-nc/4.0/), which permits any noncommer-cial use, distribution, and reproduction in anymedium, provided you give appropriate creditto the original author(s) and the source, providea link to the Creative Commons license, andindicate if changes were made.

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