Laser-assisted cataract surgery: an overview

Optometry in Practice 2014
Volume 15
Issue 2
49 – 56
Laser-assisted cataract surgery: an overview
Andreas Hartwig Dipl-Ing(FH) PhD FAAO, Sundeep Kheterpal MA FRCS MRCOphth,
Jay Dermott DOpt BSc FFDO and Clare O’Donnell PhD MBA MCOptom FAAO FBCLA
Optegra Eye Sciences, Manchester
EV-20108 C-36666
1 CET point for UK optometrists
Introduction
Cataract surgery
Cataract is the most common cause of treatable blindness
and estimates suggest that cataract accounted for around
20 million cases of blindness worldwide in 2010 (World
Heath Organization 2010). As age expectancy increases,
the number of people with cataract is expected to grow.
Cataract surgery is the most commonly performed surgical
procedure, with over 330 000 cases performed each year in
England alone (Royal College of Ophthalmologists 2010).
Although cataract surgery is considered to be very successful,
no surgery is completely without risk and complications
such as corneal oedema, raised intraocular pressure, cystoid
macular oedema, endophthalmitis, posterior capsular
opaciﬁcation and refractive surprise can still occur (Barry
et al. 2013; Jaycock et al. 2009; Lundström et al. 2013).
Therefore, the desire to strive for further reﬁnements and
improvements continues.
Cataract surgery typically involves pupillary dilation,
application of a local anaesthetic and creation of a corneal
incision or incisions to access the ocular structures.
A viscoelastic substance called an ophthalmic viscosurgical
device or OVD is used to stabilise the anterior chamber
and to help protect the integrity of the structures, including
the corneal endothelium.
Femtosecond lasers have a unique ability to create small and
discreet disruptions to tissue with minimal adverse effects to
surrounding tissues. In brief, the process involves the absorption
of femtosecond laser energy by the target tissue, which
creates a cloud of free electrons and ionised molecules which
expands and collapses rapidly. This leads to the production
of small cavitation bubbles and an acoustic shock wave that
cuts and separates the tissue (Donaldson et al. 2013; Soong
and Malta 2009; Sugar 2002). This photodisruption approach
enables precise cutting in the cornea, lens capsule and
crystalline lens. The technology has been used successfully in
corneal laser vision correction for many years (Salomao and
Wilson 2010) and it is now being applied to cataract surgery.
The ﬁrst laser-assisted refractive cataract surgery in humans
was performed in Hungary in 2008 and the technology is now
available in other countries, including the UK. It is envisaged
that femtosecond laser-assisted cataract surgery (FLACS)
may lead to further improvements in surgical, visual and
refractive outcomes.
This paper aims to provide an overview of FLACS, written for
the practising optometrist, who, as the trusted primary eye
care provider, is in an excellent position to advise patients
who may enquire about this new technology.
A circular opening in the anterior capsule (capsulorhexis)
is made by freehand tearing using forceps. Creating a
well-centred and perfectly circular capsulorhexis requires
a high level of skill and this can be especially challenging in
cases of shallow anterior chambers, mature cataract or
weak zonules. Any radial tears in the anterior capsule can
extend posteriorly, leading to possible luxation of the nucleus
into the vitreous cavity, further complications and poorer
clinical outcomes (Lundström et al. 2013). If the capsulorhexis
is too small, the nucleus may be difﬁcult to remove, the
capsule may ﬁbrose and hyperopic shift may result (Sciscio
and Liu 1999). If there is variation in the extent of contact or
areas where there is insufﬁcient contact between the capsule
circumference and the optic of the intraocular lens (IOL),
decentration, rotation or posterior capsular opaciﬁcation can
occur (Kranitz et al. 2012; Trikha et al. 2013). This can therefore
inﬂuence the refractive and visual outcomes (Kranitz et al.
2012), particularly with advanced technology implants such as
toric, accommodating or multifocal IOLs (Trikha et al. 2013).
After creating the capsulorhexis, ﬂuid is used to separate
the lens cortex from the capsule, allowing the lens to be
rotated within the capsular bag. An instrument to hold and
turn the lens and another that uses ultrasonic vibration to
fragment and aspirate the lens are then used. The nucleus
is removed by sculpting, chopping and emulsiﬁcation. The
phacoemulsiﬁcation power, pulse, aspiration rate and vacuum
parameters can be adjusted, depending on the cataract
being treated. Excessive manipulation can increase the risk
of injury to the cornea, iris or capsule (Trikha et al. 2013) and
excessive ultrasound power can also be damaging (Murano
et al. 2008). After the lens fragments have been removed, an
IOL is implanted, typically into the capsular bag. The OVD is
removed and the incision is left sutureless.
Date of acceptance: 19 May 2014. Address for correspondence: C O’Donnell, Optegra Eye Sciences, One Didsbury Point, 2 The Avenue, Didsbury,
Manchester M20 2EY, UK. [email protected]
© 2014 The College of Optometrists
49
A Hartwig et al.
Femtosecond laser-assisted cataract
surgery
Femtosecond laser technology has various applications
during cataract surgery. The laser can be used to make
the corneal incisions, create the anterior capsulotomy and
to liquefy or fragment the crystalline lens (Sutton et al.
2013; Trikha et al. 2013). The pupil is dilated and a topical
anaesthetic is administered with or without mild sedation.
There are four different systems available, but the approach
used is broadly similar across these platforms (Figure 1).
Figure 2. Docking stage.
After imaging (Figure 3) and registration, the laser aspect
of the treatment can begin, followed by lens removal using
phacoemulsiﬁcation and ﬁnally IOL implantation. The
laser part of the procedure may be carried out in a different
room from the rest of the surgery and the patient may have
to be moved in some settings. The reasons for this are that
some systems are too large for some operating theatres and
it may be that one laser may be used by more than one
operating theatre.
Figure 1. Laser-assisted cataract surgery system.
Planning the surgery includes assessing the anatomy of the
patient’s eye, including pupil diameter, anterior-chamber depth
and the thickness of the cornea and lens. The capsulotomy
size, shape and centration are planned, taking into account
the IOL being implanted. The lens fragmentation pattern is
chosen and this will inﬂuence the amount of phaco time and
power required later in the procedure. The placement, depth,
length and axis of the corneal incisions are determined.
The patient’s eye is stabilised by ‘docking’ the eye into the
laser platform using either a curved contact lens or liquid
interface-type coupling system (Figure 2). Suction pressure
can result in subconjuctival haemorrhage and redness
(Chang et al. 2014; Nagy et al. 2014; Uy et al. 2012). Some of
the docking systems have the potential to induce distortion
or compression of the cornea which can affect image quality.
Advanced cataracts can make imaging of the posterior
capsule more challenging with some systems. A temporary
increase in intraocular pressure usually occurs (Schultz et
al. 2013). When the eye is properly docked, high-resolution
imaging of the ocular structures (including the cornea, iris,
lens and posterior capsule) is possible.
50
Figure 3. Imaging stage.
The FLACS systems currently available include Lens Sx (Alcon,
Alisa Viejo, CA, USA), LensAR (LensAR, Orlando, FL, USA)
(Figure 1), VICTUS (Bausch & Lomb, Technolas Perfect Vision
Rochester, NY, USA) and Catalys (Optimedica, Santa Clara,
CA, USA). All systems include an anterior-segment imaging
system, patient interface and femtosecond laser. Differences
between systems include the imaging and docking technology
used and different treatment algorithms. Systems differ in the
Laser-assisted cataract surgery: an overview
patterns of cuts and the order in which the various steps in
the procedure are delivered. The imaging systems
incorporated are based on optical coherence tomography or
Scheimpﬂug-based imaging technology.
Donaldson et al. (2013) point out there is inconsistency
in the nomenclature and acronyms used for the FLACS
procedure, with alternatives including ReLACS (refractive
laser-assisted cataract surgery), FALCS (femtosecond-assisted
laser cataract surgery) and T-LACS (therapeutic laser-assisted
cataract surgery).
In brief, the femtosecond laser has the following applications
during cataract surgery.
Corneal incisions
The size, location and architecture of a corneal incision will
determine its effect on the postoperative cylindrical refractive
component (Klamann et al. 2013). Extracapsular cataract
incisions and suturing historically encompassed up to 180° of
the cornea, inducing large amounts of astigmatism. This was
reduced by removing sutures and some reduction naturally
occurred over time due to the healing process. The small
(<3mm) incisions used nowadays induce cylinders typically
<0.5DC (Ernest et al. 2011; Gross and Miller 1996; Samuelson
et al. 1991).
During IOL surgery the main corneal incision may be placed
temporally along the steepest corneal meridian to minimise
postoperative astigmatism. Self-sealing corneal incisions
are the method of choice for gaining access to the anterior
chamber (Leaming 2003). These incisions can be created
by a femtosecond laser. The parameters of the incision can
be important determinants for the outcome of surgery and
the femtosecond laser has the potential to provide more
precise incisions than those created manually (Masket et
al. 2010; Palanker et al. 2010). It has been suggested that
better-constructed wounds achieved with a laser may
result in faster healing times, less tissue damage and less
wound leakage and they could even reduce the risk of
endophthalmitis (Ernest et al. 1991; Masket et al. 2010;
Trikha et al. 2013). At present, the laser-created incisions are
designed to be initially incomplete, ready to be opened with
a blunt instrument, so the anterior chamber is not breached
during surgery as needed.
Clear corneal or limbal relaxing incisions (LRIs) can be
used to reduce corneal astigmatism. This involves making
incisions which straddle the steepest corneal meridian. The
parameters and location of the incisions can be adjusted to
produce the desired change in corneal power using formulae
called nomograms. The changes are essentially achieved by
ﬂattening the steep meridian. Two clear corneal incisions
are paired opposite each other in the steep meridian for
astigmatism reduction and another incision is placed for
surgical access to the anterior chamber (Amesbury and
Miller 2009). With manual or laser LRIs the risk of corneal
perforation is reduced and there is less likelihood of irregular
astigmatism being induced since the surgery is performed
further from the visual axis. Furthermore, they cause
minimal foreign-body sensation and glare and allow faster
visual recovery than clear corneal incisions (Kleiman et al.
2007). Manual creation of LRIs of the correct width and
depth can be challenging in terms of precision and safety
(Bartels et al. 2006). Laser-assisted LRIs may improve the
predictability compared to manual LRIs for correction of
lower degrees of astigmatism (Buzzonetti et al. 2009),
although for higher degrees of astigmatism, toric IOLs may be
preferred for patients undergoing IOL surgery.
Anterior capsulotomy
Creation of an accurate anterior capsulotomy during IOL
surgery is important, since its circularity and size inﬂuence
the performance of the implanted IOL (Cekic and Batman
1999, Friedman et al. 2011; Norrby 2008; Ravalico et al. 1996;
Sanders et al. 2006; Walkow et al. 1998). FLACS systems
enable the capsulotomy to be centred over the pupil centre or
over the optical axis of the crystalline lens. The optimal capsule
diameter will be determined by factors including the optic
diameter of the implant and a well-executed capsulotomy
will inﬂuence IOL stability, effective lens position and
refractive predictability and will help reduce the likelihood of
posterior-capsule opaciﬁcation (Trikha et al. 2103).
The femtosecond laser-created capsulotomy has been shown
to be more accurate in terms of its shape, centration and
diameter (Friedman et al. 2011; Nagy et al. 2009; Prasad Reddy
et al. 2013; Tackman et al. 2011). Mayer et al. (2014) suggested
that the precision and morphology of FLACS capsulotomies
may reduce the rate of posterior capsule opaciﬁcation.
The centration of the IOL has also been shown to be more
accurate (Batlle 2010; Kranitz et al. 2011; Nagy 2010) and
refractive outcomes have been shown to be closer to the target
postoperative refraction (Edwards et al. 2010, 2012; Filkorn
et al. 2012) in some FLACS studies. These data lend support to
the assertion that laser capsulotomy has a positive inﬂuence
on the consistency of effective lens position. The differences
between manual and laser-guided capsulotomy might be
even more important where more advanced lens designs such
as accommodating, multifocal or toric IOLs are being used
(Uy et al. 2011). Kranitz et al. (2011) and Nagy et al. (2011)
demonstrated decreased rates of incomplete overlap of the
capsule edge and less horizontal decentration of the IOL with
laser capsulotomy.
To create a precise opening in the anterior capsule with a
laser, it is essential that the crystalline lens is correctly aligned
during the procedure. Any tilt of the lens relative to the axis
of the laser would lead to errors in applying the laser where
intended (Bali et al. 2012). To overcome this, FLACS systems
can adjust the laser axis accordingly. It has been shown that
IOL tilt and decentration are reduced when the capsulotomy
is created using a femtosecond laser in comparison to manual
capsulorhexis (Kranitz et al. 2012). It has been suggested there
may be rare instances where it is deemed advantageous to
tilt or decentre an implanted IOL deliberately, for example, in
cases of vertical strabismus (Nishimoto et al. 2007), and this
can be accommodated with FLACS.
Capsule strength studies have shown that capsulotomies
created with a laser are stronger, needing more force to stretch
51
A Hartwig et al.
compared to manually created capsulorhexes (Auffarth
et al. 2013; Frey et al. 2009; Friedman et al. 2011; Nagy et
al. 2009; Palanker et al. 2010). Even though there appear
to be clear beneﬁts of femtosecond laser surgery, there are
also some potential risks. Abell et al. (2014) showed that
an increase in capsule tears can occur and noted irregular
‘postage stamp’ perforations at the capsule margin in
some FLACS capsulotomies, as seen by scanning electron
microscopy (SEM). Using light and SEM, Ostovic et al. (2013)
showed that, although laser-assisted capsulotomy specimens
appeared rounder, more tags, bridges, rougher edges and
demarcation lines at the capsulotomy edge were seen
compared to the manual capsulorhexes. They suggested this
may be due to minimal torsional eye movements during laser
surgery and these effects may be reduced by using a liquid
immersion/soft patient interface and lowering the pulse
energy used. In their SEM study, Mastropasqua et al. (2013)
reported that FLACS capsulotomy resulted in better geometry
and circularity and more homogeneous edge thickness.
Smoother cut surfaces were seen in the manual group, with
the degree of irregularity inﬂuenced by increasing energy
settings in the femtosecond laser group. The authors
suggested that future studies should aim to identify the
optimum settings to use in femtosecond laser surgery.
FLACS has been associated with a higher risk of capsular
block syndrome, where gas is thought to accumulate
within the lens, causing it to expand in volume. The edge
of the laser capsulotomy forms a seal around the expanded
nucleus, restricting ﬂuid ﬂow and resulting in pressure on
the capsule, posterior capsular rupture and lens dislocation
(Roberts et al. 2011). Awareness and modiﬁcation of
technique help to avoid this.
Lens liquefaction and fragmentation
The femtosecond laser can be used for softening and
fragmenting the lens (Donaldson et al. 2013; He et al. 2011;
Nagy 2012).
The FLACS treatment algorithms are optimised for
different grades of cataract. The technology enables lower
ultrasound energy levels to be applied for additional safety
to the corneal endothelium (Acar et al. 2011; Murano et al.
2008; Prasad Reddy et al. 2013) and faster visual recovery
(Edwards et al. 2010; He et al. 2011; Takacs et al. 2012).
Nagy et al. (2009) reported that the use of the femtosecond
laser resulted in a 43% reduction in phacoemulsiﬁcation
power and a 51% reduction in phacoemulsiﬁcation time.
The time spent on phacoemulsiﬁcation after pretreatment
with a femtosecond laser is signiﬁcantly shorter than
performing phacoemulsiﬁcation alone (Abell et al. 2013a, b;
Conrad-Hengerer et al. 2012a). Abell et al. (2013c) suggested
that anterior-segment inﬂammation may be less after FLACS
than after manual surgery and suggested this may be due to
reduced phacoemulsiﬁcation energy.
Attempts to demonstrate whether some fragmentation
patterns (Figure 4) are superior to others in terms of reducing
phacoemulsiﬁcation time are under way (Conrad-Hengerer
et al. 2012b; Donaldson et al. 2013). Trikha et al. (2013)
suggest that an ultimate aim may be to develop algorithms
that avoid the need for any ultrasound energy at all. Kelkar
52
et al. (2008) suggested that, whenever more instruments are
introduced into the eye during surgery, there is a potential
increase in the risk of endophthalmitis. Whether using a laser
could reduce the number of instruments required during
surgery and therefore could potentially further reduce the risk
of infection remains to be seen.
Figure 4. Fragmentation pattern.
Experience with FLACS
Emerging data from published studies that have evaluated
FLACS in humans provide evidence that the technique can
provide good visual outcomes and reduced complications and
there appear to be no signiﬁcant safety concerns.
As stated above, correct docking is important and
misalignment or slipping of the eye during the treatment can
mean suction is lost. The creation of corneal incisions and
capsulorhexis takes only a few seconds, so suction loss during
this part of the procedure is rare (Donaldson et al. 2013).
When comparing a curved contact lens interface with a liquid
optical immersion interface, it was shown that the curved
contact lens interface can lead to corneal folds which can
adversely affect the capsulotomy. Using a liquid interface,
corneal folds were not observed and the stability of the eye
during the procedure was enhanced. Fewer subconjunctival
haemorrhages and reduced IOP increase were also observed
(Donaldson et al. 2013; Talamo et al. 2013).
Contraindications
It is necessary to bear in mind that cataract surgery using
a femtosecond laser needs dilation of the pupil and poor
dilation and posterior synechiae are relative contraindications.
Other relative contraindications include corneal opacities
(which may affect absorption of the laser) or conditions
leading to instability of the lens. Although the level of increase
in IOP has been shown to be modest compared to that seen
in other laser procedures (Kerr et al. 2013), the FLACS
approach may not be appropriate in cases of advanced
Laser-assisted cataract surgery: an overview
glaucoma or visual ﬁeld loss. Poor mobility, tremor,
nystagmus, attention deﬁcit disorders, inability to lie ﬂat,
deep-set eyes and narrow palpebral apertures are additional
relative contraindications to FLACS (Donaldson et al. 2013;
Trikha et al. 2013). Trikha et al. (2013) suggest there are
limitations regarding the grade and nature of the cataract
that can be treated. They suggest lens fragmentation is only
possible to Lens Opacities Classiﬁcation System (LOCS)
grade 4.0 and that posterior subcapsular cataracts may also
require an alternative approach. It is essential that the
patient’s head can be correctly positioned for docking.
Retina
Another important factor may be the inﬂuence of the laser
on the retina. Palanker et al. (2010) showed that there was
no evidence of retinal damage caused by the laser in rabbit
eyes. In addition it was found that the thickening of the inner
macular ring and macular oedema were signiﬁcantly less
when the femtosecond laser was used for lens fragmentation,
perhaps due to reduced phacoemulsiﬁcation energy, as
described above (Ecsedy et al. 2011; Nagy et al. 2012).
Conclusion
In conclusion, FLACS potentially provides several advantages
over standard cataract surgery. It is expected that, as
surgeons and patients become more familiar with this
approach, laser-assisted surgery may become an established
component of cataract surgery in future. It is likely that
there will be reﬁnements to IOLs, with new models being
designed especially for this purpose.
Hundreds of thousands of femtosecond laser-assisted
cataract surgical procedures have already been performed
worldwide. Although the potential for better outcomes and
safety proﬁles is clearly promising, the technology is costly
and detractors point out that there is no deﬁnitive evidence
yet proving its superiority over conventional small-incision
phacoemulsiﬁcation surgery. However, FLACS is still in its
infancy and it has been proposed that widespread acceptance
will be inﬂuenced by the emerging scientiﬁc evidence and
socioeconomic factors in the coming years (Trikha et al. 2013).
In the meantime the practising optometrist is in an excellent
position to advise and educate patients about this exciting
new technology.
‘Learning curve’
There is a ‘learning curve’ associated with the procedure and,
in a report on early experience with FLACS, the average time
spent in the theatre was slightly longer when applying the
femtosecond laser compared to conventional surgery (Bali
et al. 2012). It is expected that the procedure time will
reduce as the clinical teams become more familiar with the
technology and workﬂow. It was shown that with experience
the number of docking attempts required tends to decrease
(Nagy et al. 2014; Roberts et al. 2013) and similarly there
was a trend towards fewer complications (Bali et al. 2012;
Nagy et al. 2014; Roberts et al. 2013).
It has been suggested that FLACS may allow less experienced
surgeons to obtain better results, but it may fail to
demonstrate signiﬁcant improvements for experienced
surgeons not implanting advanced-technology IOLs (Trikha
et al. 2013). With time it may be that FLACS becomes the
preferred method for dealing with more complex cataract
cases (Conrad-Hengerer et al. 2013; Trikha et al. 2013).
Despite the potential beneﬁts, there is a high cost in
implementing this technology and the use of FLACS is not yet
widespread. With time, increasing awareness and evidence
from longer-term prospective randomised controlled trials,
this may change and FLACS may well become the standard of
care in future.
Other applications
Femtosecond lasers have been shown to bleach the
crystalline lens, decreasing the amount of age-induced yellow
discoloration, and it has been suggested that they could be
used to postpone the need for cataract surgery by several
years (Kessel et al. 2010). Another possible application is
using the femtosecond laser to provide some restoration of
accommodation ability to presbyopic patients by creating
sliding planes within the lens and trials are currently under way
(Krueger et al. 2005).
Images courtesy of LensAR.
Summary
Cataract surgery has gone through a number of
advancements from extraction of the whole lens
through a large incision requiring stitches to the current
use of an ultrasound probe to break up, emulsify
and remove lens fragments through small sutureless
incisions. Such advances in technology, combined with
the utilisation of new types of IOLs, have led to a high
degree of safety and predictability and contributed to
improved outcomes for patients. Although cataract
surgery is considered to be safe and efﬁcacious, success
is highly dependent on the skill of the surgeon to
make the incisions manually, open the capsule and
apply ultrasound energy to break up and remove the
lens safely.
Femtosecond laser technology has been used in corneal
procedures for many years now, including the creation of
the ﬂap in laser in situ keratomileusis (LASIK). It is now
being applied to cataract and lens replacement surgery.
In laser-assisted cataract surgery, the laser can be used
by the surgeon to make the surgical incisions, create
the anterior capsulotomy and break up the crystalline
lens. The surgeon then utilises the same techniques as
in standard cataract surgery, to remove and replace
the lens. It is suggested that this approach offers the
potential for even safer and more precise surgery, which
could lead to further improvements in clinical outcomes
for patients.
This paper aims to provide an overview of FLACS and
the studies that have attempted to evaluate it. The
potential risks, beneﬁts and criteria for patient selection
are discussed.
53
A Hartwig et al.
References
Abell RG, Kerr NM, Vote BJ (2013a) Toward zero effective
phacoemulsiﬁcation time using femtosecond laser pretreatment.
Ophthalmology 120, 942–8
Abell RG, Kerr NM, Vote BJ (2013b) Femtosecond laser assisted
cataract surgery compared with conventional cataract surgery.
Clin Experiment Ophthalmol 41, 455–62
Abell RG, Allen PL, Vote BJ (2013c) Anterior chamber ﬂare after
femtosecond laser-assisted cataracts surgery. J Cataract Refract
Surg 39, 1321–6
Abell RG, Davies PE, Phelan D et al. (2014) Anterior capsulotomy
integrity after femtosecond laser assisted cataract surgery.
Ophthalmology 121, 17–24
Acar BT, Buttanri IB, Sevim MS et al. (2011). Corneal endothelial
cell loss in post-penetrating keratoplasty patients after cataract
surgery: phacoemulsiﬁcation versus planned extracapsular
cataract extraction. J Cataract Refract Surg 37, 1512–16
Amesbury EC, Miller KM (2009) Correction of astigmatism at
the time of cataract surgery. Curr Opin Ophthalmol 20, 19–24
Auffarth GU, Reddy KP, Ritter R et al. (2013) Comparison of
the maximum applicable stretch force after femtosecond laser
assisted and manual anterior capsulotomy. J Cataract Refract
Surg 39, 105–9
Bali SJ, Hodge C, Lawless M et al. (2012) Early experience
with the femtosecond laser for cataract surgery. Ophthalmology
119, 891–9
Barry P, Cordoves L, Gardner S (2013) ESCRS Guidelines for
Prevention and Treatment of Endophthalmitis Following Cataract
Surgery. Data, Dilemmas and Conclusions. Available online at:
www.escrs.org (accessed 1 April 2014)
Bartels MC, Saxena R, van den Berg TJ et al. (2006) The inﬂuence
of incision-induced astigmatism and axial lens position on the
correction of myopic astigmatism with the Artisan toric phakic
intraocular lens. Ophthalmology 113, 1110–17
Batlle J (2010) Prospective study of size and shape accuracy
of Optimedica femtosecond laser capsulotomy vs. manual
capsulorhexis. Program and Abstracts of XXVIII Congress of the
ESCRS, Paris, France
Buzzonetti L, Petrocelli G, Laborante A et al. (2009) Arcuate
keratotomy for high postoperative keratoplasty astigmatism
performed with the intralase femtosecond laser. J Refract Surg
25, 709–14
Cekic O, Batman C (1999) The relationship between
capsulorhexis size and anterior chamber depth relation.
Ophthalmic Surg Lasers 30, 185–90
Chang JSM, Chen IN, Chan W-M et al. (2014) Initial evaluation
of a femtosecond laser system in cataract surgery. J Cataract
Refract Surg 40, 29–36
Conrad-Hengerer I, Hengerer FH, Schultz T et al. (2012a). Effect
of femtosecond laser fragmentation of the nucleus with different
softening grid sizes on effective phaco time in cataract surgery.
J Cataract Refract Surg 38, 1888–94
54
Conrad-Hengerer I, Hengerer FH, Schultz T et al. (2012b)
Effect of femtosecond laser fragmentation on effective
phacoemulsiﬁcation time in cataract surgery. J Refract Surg
28, 879–83
Conrad-Hengerer I, Dick HB, Schultz T et al. (2013) Femtosecond
laser-assisted capsulotomy after penetrating injury of the
corneal and lens capsule. J Cataract Refract Surg 40, 153–6
Donaldson KE. Braga-Mele R, Cabot F et al. (2013).
Femtosecond laser-assisted cataract surgery. J Cataract Refract
Surg 39, 1753–63
Ecsedy M, Mihaltz K, Kovacs I et al. (2011) Effect of femtosecond
laser cataract surgery on the macula. J Refract Surg 27, 717–22
Edwards KH, Frey RW, Naranjo-Tackman R et al. (2010) Clinical
outcomes following laser cataract surgery. Invest Ophthalmol
Vis Sci 51 (e-abstract 5394)
Edwards KH, Hill W, Uy HS et al. (2012) Improvement in the
achievement of targeted post-operative MRSE with laser
anterior capsulotomy matches the theoretical model. ARVO.
Fort Lauderdale, FL
Ernest PH, Kiessling LA, Lavery KT (1991) Relative strength
of cataract incisions in cadaver eyes. J Cataract Refract Surg
17 (Suppl), 668–71
Ernest P, Hill W, Potvin R (2011) Minimizing surgically induced
astigmatism at the time of cataract surgery using a square
posterior limbal incision. J Ophthalmol 243170
Filkorn T, Kovacs I, Takacs A et al. (2012) Comparison of IOL
power calculation and refractive outcomes after laser refractive
cataract surgery with a femtosecond laser versus conventional
phacoemulsiﬁcation. J Refract Surg 28, 540–4
Frey RW, Teuma EV, O’Suilleabhain D et al. (2009) Evaluation of
the mechanical properties of the crystalline lens capsule following
photodisruption capsulotomy and continuous curvilinear
capsulorrhexis. Invest Ophthalmol Vis Sci E-abstract 1141
Friedman NJ, Palanker DV, Schuele G et al. (2011) Femtosecond
laser capsulotomy. J Cataract Refract Surg 37, 1189–98
Gross RH, Miller KM (1996) Corneal astigmatism after
phacoemulsiﬁcation and lens implantation through unsutured
scleral and corneal tunnel incisions. Am J Ophthalmol 121, 57–64
He L, Sheehy K, Culbertson W (2011) Femtosecond laser-assisted
cataract surgery. Curr Opin Ophthalmol 22, 43–52
Jaycock P, Johnston RL, Taylor H et al. (2009) Cataract National
Dataset electronic multicenter audit of 55 567 operations:
updating benchmark standards of care in the United Kingdom
and internationally. Eye 23, 38–49
Kelkar A, Kelkar J, Amuaku W et al. (2008) How to prevent
endophthalmitis in cataract surgeries? Ind J Ophthalmol
56, 403–7
Kerr NM, Abell RG, Vote BJ et al. (2013) Intraocular pressure
during femtosecond laser pretreatment of cataract. J Cataract
Refract Surg 39, 339–42
Kessel L, Eskildsen L, van der Poel M et al. (2010). Non-invasive
bleaching of the human lens by femtosecond laser photolysis.
PLoS One 5, e9711
Laser-assisted cataract surgery: an overview
Klamann MK, Gonnermann J, Maier AK et al. (2013) Smaller
incision size leads to higher predictability in microcoaxial
cataract surgery. Eur J Ophthalmol 23, 202–7
Nagy ZZ, Takacs A, Filkorn T et al. (2014) Complications of
femtosecond laser-assisted cataract surgery. J Cataract Refract
Surg 40, 20–8
Kleiman LZ, Oleynikov YS, and Gorman BD (2007) Astigmatic
considerations in cataract surgery. NJ, USA: B. Henderson and
N. Slack
Nishimoto H, Shimizu K, Ishikawa H et al. (2007) New approach
for treating vertical strabismus: decentered intraocular lenses.
J Cataract Refract Surg 33, 993–8
Kranitz K, Takacs A, Mihaltz K et al. (2011) Femtosecond laser
capsulotomy and manual continuous curvilinear capsulorrhexis
parameters and their effects on intraocular lens centration.
J Refract Surg 27, 558–63
Norrby S (2008) Sources of error in intraocular lens power
calculation. J Cataract Refract Surg 34, 368–76
Kranitz K, Mihaltz K, Sandor GL et al. (2012) Intraocular lens tilt
and decentration measured by Scheimpﬂug camera following
manual or femtosecond laser-created continuous circular
capsulotomy. J Refract Surg 28, 259–63
Krueger RR, Kuszak J, Lubatschowski H et al. (2005) First safety
study of femtosecond laser photodisruption in animal lenses:
tissue morphology and cataractogenesis. J Cataract Refract
Surg 31, 2386–94
Leaming DV (2003) Practice styles and preferences of ASCRS
members - 2002 survey. J Cataract Refract Surg 29, 1412–20
Lundström M, Barry P, Henry Y et al. (2013) Visual outcome of
cataract surgery: study from the European Registry of Quality
Outcomes for Cataract and Refractive Surgery. J Cataract
Refract Surg 39, 673–9
Masket S, Sarayba M, Ignacio T et al. (2010) Femtosecond
laser-assisted cataract incisions: architectural stability and
reproducibility. J Cataract Refract Surg 36, 1048–9
Mastropasqua L, Toto L, Calienno R et al. (2013) Scanning
electron microscopy evaluation of capsulorhexis in femtosecond
laser-assisted cataract surgery. J Cataract Refract Surg 39, 1581–6
Mayer WJ, Klaproth OK, Ostovic M (2014) Cell death and
ultrastructural morphology of femtosecond laser-assisted
anterior capsulotomy. Invest Ophthalmol Vis Sci 55, 893–8
Murano N, Ishizaki M, Sato S et al. (2008) Corneal endothelial
cell damage by free radicals associated with ultrasound
oscillation. Arch Ophthalmol 126, 816–21
Nagy ZZ (2010) Comparative analysis of the femtolaser-assisted
and manual capsulorhexis during phacoemulsiﬁcation. Program
and Abstracts of XXVII Congress of the ESCRS, Paris, France
Nagy ZZ (2012) Advanced technology IOLs in cataract
surgery: pearls for successful femtosecond cataract surgery.
Int Ophthalmol Clin 52,103–14
Nagy ZZ, Takacs A, Filkorn T et al. (2009) Initial clinical
evaluation of an intraocular femtosecond laser in cataract
surgery. J Refract Surg 25, 1053–60
Nagy ZZ, Kránitz K, Takacs AI et al. (2011) Comparison of
intraocular lens decentration parameters after femtosecond
and manual capsulotomies. J Cataract Surg 27, 564–9
Nagy ZZ, Ecsedy M, Dovacs I et al. (2012) Macular morphology
assessed by optical coherence tomography image segmentation
after femtosecond laser-assisted and standard cataract surgery.
J Cataract Refract Surg 38, 941–6
Ostovic M, Klaproth OK, Hengerer FH et al. (2013) Light
microscopy and scanning electron microscopy analysis
of rigid curved interface femtosecond laser-assisted and
manual capsulotomy. J Cataract Refract Surg 39, 1597–92
Palanker DV, Blumenkranz MS, Andersen D et al. (2010)
Femtosecond laser-assisted cataract surgery with integrated
optical coherence tomography. Sci Transl Med 2, 58ra85
Prasad Reddy K, Kandulla J, Auffarth GU (2013) Effectiveness
and safety of femtosecond laser-assisted lens fragmentation and
anterior capsulotomy versus the manual technique in cataract
surgery. J Cataract Refract Surg 39, 1297–306
Ravalico G, Tognetto D, Palomba M et al. (1996). Capsulorhexis
size and posterior capsule opaciﬁcation. J Cataract Refract Surg
22, 98–103
Roberts TV, Sutton G, Lawless MA et al. (2011) Capsular block
syndrome associated with femtosecond laser-assisted cataract
surgery. J Cataract Refract Surg 37, 2068–70
Roberts TV, Lawless M, Bali SJ et al. (2013) Surgical outcomes
and safety of femtosecond laser cataract surgery: a prospective
study of 1500 consecutive cases. Ophthalmology 120, 227–33
Royal College of Ophthalmologists (2010) Cataract Surgery
Guidelines. Available online at: www.rcophth.ac.uk (accessed
1 May 2014)
Salomao MQ, Wilson SE (2010) Femtosecond laser in situ
keratomileusis. J Cataract Refract Surg 36, 1024–32
Samuelson SW, Koch DD, Kuglen CC (1991) Determination
of maximal incision length for true small-incision surgery.
Ophthalmic Surg 22, 204–7
Sanders DR, Higginbotham RW, Opatowsky IE et al. (2006)
Hyperopic shift in refraction associated with implantation of
the single-piece Collamer intraocular lens. J Cataract Refract
Surg 32, 2110–12
Schultz T, Conrad-Hengerer I, Hengerer FH et al. (2013)
Intraocular pressure variation during femtosecond laser-assisted
cataract surgery using a ﬂuid-ﬁlled interface. J Cataract Refract
Surg 39, 22–27
Sciscio A, Liu C (1999) Anterior capsular phimosis following
Acrysof lens insertion. Br J Ophthalmol 83, 989–90
Soong HK, Malta JB (2009) Femtosecond lasers in ophthalmology.
Am J Ophthalmol 147, 189–97
Sugar A (2002) Ultrafast (femtosecond) laser refractive surgery.
Curr Opin Ophthalmol 13, 246–9
Sutton G, Bali SJ, Hodge C (2013) Femtosecond cataract surgery:
transitioning to laser cataract. Curr Opin Ophthalmol 24, 3–8
55
A Hartwig et al.
Tackman RN., Kuri JV, Nichamin LD et al. (2011) Anterior
capsulotomy with an ultrashort-pulse laser. J Cataract Refract
Surg 37, 819–24
Takacs AL, Kovacs I, Mihaltz K et al. (2012) Central corneal
volume and endothelial cell count following femtosecond
laser-assisted refractive cataract surgery compared to
conventional phacoemulsiﬁcation. J Refract Surg 28, 387–91
Talamo JH, Gooding P, Angeley D et al. (2013) Optical patient
interface in femtosecond laser-assisted cataract surgery:
Contact corneal applanation versus liquid immersion. J Cataract
Refract Surg 39, 501–10
3. How is the tissue cut in laser-assisted cataract surgery?
(a) Photodisruption
(b) Photoablation
(c) Photocoagulation
(d) Phacoemulsiﬁcation
4. Which one of the following steps is not performed with
the laser during FLACS?
(a) Anterior capsulotomy
(b) Phacoemulsiﬁcation
Trikha S, Turnbull AM, Morris RJ et al. (2013) The journey to
femtosecond laser-assisted cataract surgery: new beginnings or
a false dawn? Eye 27, 461–73
(c) Making the incisions
Uy HS, Hill W, Edwards KH (2011) Refractive results after
laser anterior capsulotomy. ARVO. A4695 Poster D634. Fort
Lauderdale, FL
5. Which one of the following steps is not part of the
standard FLACS procedure?
Uy HS, Edwards KH, Curtis N (2012) Femtosecond
phacoemulsiﬁcation: the business and the medicine. Curr Opin
Ophthalmol 12, 33–9
(b) High-resolution imaging
Walkow T, Anders N, Pham DT et al. (1998) Causes of severe
decentration and subluxation of intraocular lenses. Graefes
Arch Clin Exp Ophthalmol 236, 9–12
(d) Postoperative suturing
World Health Organization (2010) Global Data on Visual
Impairments 2010. Available online at: http://www.who.int/en/
(accessed 1 May 2014)
(a) Very small pupil
(d) Phacofragmentation
(a) Docking the eye
(c) Planning the surgery
6. Which of the following may be a relative contraindication
for FLACS?
(b) Advanced glaucoma
(c) Dense corneal opacities
CET multiple choice questions
This article has been approved for one non-interactive
point under the GOC’s Enhanced CET Scheme. The reference
and relevant competencies are stated at the head of the
article. To gain your point visit the College’s website
www.college-optometrists.org/oip and complete the multiple
choice questions online. The deadline for completion is
31 July 2015.
1. Which one of the following is a not a potential advantage
of FLACS in the removal of cataracts?
(a) It is safer
(b) It is more precise
(c) IOL positioning is better
(d) It is suitable for all patients
2. What type of laser is used in FLACS?
(a) Nd:YAG
(b) Femtosecond
(c) Excimer
(d) Argon
56
(d) All of the above
CPD Exercise
After reading this article can you identify areas in which
your knowledge of laser-assisted cataract surgery has
been enhanced?
How do you feel you can use this knowledge to offer
better patient advice?
Are there any areas you still feel you need to study and
how might you do this?
Which areas outlined in this article would you beneﬁt
from reading in more depth, and why?
Laser-assisted cataract surgery: an overview
Reﬂection
1. What impact has your learning had, or might it have, on:
• your patients or other service users (eg those who refer
patients to you, members of staff whom you supervise)?
• yourself (improved knowledge, performance, conﬁdence)?
• your colleagues?
2. How might you assess/measure this impact?
To access CPD Information please click on the following link:
college-optometrists.org/cpd
57

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