*4.3.2 Pupillary constriction*

The incidence of pupillary constriction is 19% and arises during the first steps of the femtolaser procedure [19]. The laser application itself can cause pupillary miosis. Bubble formation in the anterior chamber releases small amounts of free radicals and prostaglandins that can trigger pupillary constriction. Highly myopic eyes and eyes with pseudoexfoliation syndrome are prone to a miotic reaction after femtosecond laser treatment. Intracameral epinephrine before lens removal can help enlarge the pupil and facilitate the surgery [26]. Iris hooks, retractors or a


#### **Table 4.**

*Rate of complications.*

Malyugin ring can be placed after the laser procedure if miosis results. In a case of insufficient mydriasis and an ectopic pupil, Malyugin et al. have developed a surgical technique that combines use of an iris hook and a pupil expansion ring followed by FLACS [27]. Prophylaxis may be an adapted management of the procedure. If the patient is operated immediately after the femtolaser, the prostaglandins released hardly have the time to have effect on the sphincter pupillae. Moreover, pupil dilatation should start 1 hour before, with more frequent instillation of mydriatics.

#### *4.3.3 Capsule complications*

### *4.3.3.1 Incomplete capsulorhexis and anterior capsule tear*

A recent meta-analysis shows that the number of anterior capsule and posterior capsule tears for both FLACS and manual phacoemulsification cataract surgery are low, around 0.02% [2]. Tilt, improper docking, loss of suction, corneal folds, and imaging or programming errors can cause partial a capsulotomy. Capsule tags and bridges are usually harmless if they are detected early [28]. The crucial step for capsulotomy removal is to follow the line of the femtosecond laser cut. The absence of a gutter and the presence of bubbles trapped under the capsulotomy cut are signs that help the surgeon identify minor remaining capsule attachments. The surgeon should never pull toward the center of the micro adhesion area because it can cause tags which may run out toward the periphery during hydrodissection or phacoemulsification. One should detach it capsule circumferentially following the contour of the capsulotomy. As small tags can be difficult to see, pulling out the entire anterior capsule with sudden movement is not recommended.

When an anterior capsule tear occurs, the surgeon should perform a very gentle hydrodissection and the canula should be placed 90 degrees from the tear. Avoiding the area of the anterior capsule tear and nucleus rotation is highly advised. During IOL implantation, the leading haptic should be kept away from the tear line.

#### *4.3.3.2 Capsular block syndrome*

Capsular block syndrome (CBS) is a rare (0.001%) but serious complication [19]. If hydrodissection with a high-speed influx of fluid is performed, the gas contained in the nucleus cannot access to the anterior chamber, creating an acute intra-capsular high pressure. The subsequent capsular high pressure may lead to a posterior capsular rupture with dropped nucleus. The main signs are the quick constriction of the iris, iris prolapse through the main incision, wrinkling of the capsule and tilting of the lens. Surgeons should be aware of this complication and

**29**

*Femto Laser-Assisted Cataract Surgery*

*4.3.3.3 Posterior capsular rupture*

*4.3.4 Endothelial damage*

as during a manual phacoemulsification.

*DOI: http://dx.doi.org/10.5772/intechopen.88821*

avoid it by releasing the gas and decompressing the capsular bag before starting hydrodissection. The nucleus may be gently rocked to allow this gas to be burped out. This rock'n roll technique allows air bubbles to leave the crystalline lens. When the gas bubbles leave the intralenticular plane toward the anterior chamber or leave the eye completely, there is no further danger of CBS or posterior capsular rupture.

Half of posterior capsular tears and lens dislocations are caused by posterior extension of an anterior radial tear. It is imperative that the notches at the anterior capsular margin are recognized and managed during the capsulotomy removal. Completing nuclear fracture centrally to allow any retrolenticular gas to escape is advised. In case of posterior capsular rupture, the management should be the same

In the first studies, the capsular complication rate during the learning curve (first 200 FLACS procedures) was 7.5% and then decreased to 0.62% (consecutive 1300 cases) [29, 30]. The overall incidence of posterior capsular tears was 3.5% and that of posterior lens dislocation was 2% [30]. In more recent studies, posterior capsular tears have been reported to vary between 0.53 and 1.9%, whereas the incidence of a dropped nucleus has been reported to be between 0.1 and 0.12% [31]. The debate is ongoing: in a recent meta-analysis, Day et al., including 1700 eyes, found that FLACS did not significantly lower the rate of posterior capsular rupture, which was very low in both the FLACS group and manual phacoemulsification group [2]. Though, Popovic et al., including 15,000 eyes, showed that FLACS was associated with higher rates of posterior capsular tears (risk ratio 3.73, p < 0.05) [32]. In both studies, the incidence was very low (0.02%) [32]. FLACS might be safer than manual phacoemulsification: lately, Scott et al published the first study with a statistically significant decrease of vitreous loss rate in the FLACS group compared with manual phacoemulsification group (0.65

vs. 1.65%) with a decrease in the individual surgeon's vitreous loss rate [29].

incision line could be observed 1 year after surgery [19].

*4.3.5 Wrong corneal incision localization*

decreased to become very rare (0.002%) [32].

**4.4 Personal experience and tips for success**

Endothelial damage during capsulotomy should be considered as a serious complication of femtosecond laser treatment. This complication was likely caused by the lack of an integrated OCT system with the first devices. Highly hyperopic eyes with a shallow anterior chamber require closer attention to avoid endothelial cuts. In the published cases, the overall incidence was very low (0.002%) and there were no long-term visual consequences of this complication although the endothelial

During corneal wound creation with the femtosecond laser system, if the wound is too central, it can cause surgically induced astigmatism. On the opposite, if the wound is too peripheral, it cannot be opened. Since real-time OCT devices allow visual control of the procedure, the incidence of this complication has dramatically

In our experience, with the new platforms, all capsulotomies are complete and we have not seen capsular tears. Depending of the device, the docking is relatively easy. The Catalys device, with its Liquid Optic Interface allows for easy docking without

#### *Femto Laser-Assisted Cataract Surgery DOI: http://dx.doi.org/10.5772/intechopen.88821*

*Eyesight and Imaging - Advances and New Perspectives*

*4.3.3 Capsule complications*

**Table 4.**

*Rate of complications.*

*4.3.3.2 Capsular block syndrome*

*4.3.3.1 Incomplete capsulorhexis and anterior capsule tear*

entire anterior capsule with sudden movement is not recommended.

Malyugin ring can be placed after the laser procedure if miosis results. In a case of insufficient mydriasis and an ectopic pupil, Malyugin et al. have developed a surgical technique that combines use of an iris hook and a pupil expansion ring followed by FLACS [27]. Prophylaxis may be an adapted management of the procedure. If the patient is operated immediately after the femtolaser, the prostaglandins released hardly have the time to have effect on the sphincter pupillae. Moreover, pupil dilatation should start 1 hour before, with more frequent instillation of mydriatics.

Conjunctival hemorrhage 34% Pupillary constriction 19% Suction break 2% Capsule complications 2% Posterior rupture 0.53–1.9% Anterior tear 0.02% Block syndrome 0.001% Endothelial damages 0.002% Wrong corneal incison localization 0.002%

A recent meta-analysis shows that the number of anterior capsule and posterior capsule tears for both FLACS and manual phacoemulsification cataract surgery are low, around 0.02% [2]. Tilt, improper docking, loss of suction, corneal folds, and imaging or programming errors can cause partial a capsulotomy. Capsule tags and bridges are usually harmless if they are detected early [28]. The crucial step for capsulotomy removal is to follow the line of the femtosecond laser cut. The absence of a gutter and the presence of bubbles trapped under the capsulotomy cut are signs that help the surgeon identify minor remaining capsule attachments. The surgeon should never pull toward the center of the micro adhesion area because it can cause tags which may run out toward the periphery during hydrodissection or phacoemulsification. One should detach it capsule circumferentially following the contour of the capsulotomy. As small tags can be difficult to see, pulling out the

When an anterior capsule tear occurs, the surgeon should perform a very gentle hydrodissection and the canula should be placed 90 degrees from the tear. Avoiding the area of the anterior capsule tear and nucleus rotation is highly advised. During IOL implantation, the leading haptic should be kept away from the tear line.

Capsular block syndrome (CBS) is a rare (0.001%) but serious complication [19]. If hydrodissection with a high-speed influx of fluid is performed, the gas contained in the nucleus cannot access to the anterior chamber, creating an acute intra-capsular high pressure. The subsequent capsular high pressure may lead to a posterior capsular rupture with dropped nucleus. The main signs are the quick constriction of the iris, iris prolapse through the main incision, wrinkling of the capsule and tilting of the lens. Surgeons should be aware of this complication and

**28**

avoid it by releasing the gas and decompressing the capsular bag before starting hydrodissection. The nucleus may be gently rocked to allow this gas to be burped out. This rock'n roll technique allows air bubbles to leave the crystalline lens. When the gas bubbles leave the intralenticular plane toward the anterior chamber or leave the eye completely, there is no further danger of CBS or posterior capsular rupture.

### *4.3.3.3 Posterior capsular rupture*

Half of posterior capsular tears and lens dislocations are caused by posterior extension of an anterior radial tear. It is imperative that the notches at the anterior capsular margin are recognized and managed during the capsulotomy removal. Completing nuclear fracture centrally to allow any retrolenticular gas to escape is advised. In case of posterior capsular rupture, the management should be the same as during a manual phacoemulsification.

In the first studies, the capsular complication rate during the learning curve (first 200 FLACS procedures) was 7.5% and then decreased to 0.62% (consecutive 1300 cases) [29, 30]. The overall incidence of posterior capsular tears was 3.5% and that of posterior lens dislocation was 2% [30]. In more recent studies, posterior capsular tears have been reported to vary between 0.53 and 1.9%, whereas the incidence of a dropped nucleus has been reported to be between 0.1 and 0.12% [31]. The debate is ongoing: in a recent meta-analysis, Day et al., including 1700 eyes, found that FLACS did not significantly lower the rate of posterior capsular rupture, which was very low in both the FLACS group and manual phacoemulsification group [2]. Though, Popovic et al., including 15,000 eyes, showed that FLACS was associated with higher rates of posterior capsular tears (risk ratio 3.73, p < 0.05) [32]. In both studies, the incidence was very low (0.02%) [32]. FLACS might be safer than manual phacoemulsification: lately, Scott et al published the first study with a statistically significant decrease of vitreous loss rate in the FLACS group compared with manual phacoemulsification group (0.65 vs. 1.65%) with a decrease in the individual surgeon's vitreous loss rate [29].

#### *4.3.4 Endothelial damage*

Endothelial damage during capsulotomy should be considered as a serious complication of femtosecond laser treatment. This complication was likely caused by the lack of an integrated OCT system with the first devices. Highly hyperopic eyes with a shallow anterior chamber require closer attention to avoid endothelial cuts. In the published cases, the overall incidence was very low (0.002%) and there were no long-term visual consequences of this complication although the endothelial incision line could be observed 1 year after surgery [19].

#### *4.3.5 Wrong corneal incision localization*

During corneal wound creation with the femtosecond laser system, if the wound is too central, it can cause surgically induced astigmatism. On the opposite, if the wound is too peripheral, it cannot be opened. Since real-time OCT devices allow visual control of the procedure, the incidence of this complication has dramatically decreased to become very rare (0.002%) [32].

#### **4.4 Personal experience and tips for success**

In our experience, with the new platforms, all capsulotomies are complete and we have not seen capsular tears. Depending of the device, the docking is relatively easy. The Catalys device, with its Liquid Optic Interface allows for easy docking without

posterior corneal folds. Laser induced miosis can be managed by adding 0.5% tropicamide drops in the liquid filled into the patient interface. We have not seen capsular blockage syndrome as we gently rock the nucleus to remove the gas bubbles trapped into the capsule before performing hydrodissection. We recommend the hydrodissection to be soft but complete. Phacoemulsification is easier after laser treatment but should be performed cautiously by the beginner. All the fragment patterns among the different devices effectively cut the nucleus and allow for easy disassembly. The ice-cube pattern available with the Victus is for us the more efficient pattern, as the surgeon only has to separate the first ice cubes to quickly remove all the nucleus.

TIPS FOR SUCCESS


In conclusion, FLACS increases the ease and predictability of the steps involved in cataract surgery but has a surgical learning curve and most of the complications occur during the first 100 procedures [19]. Greater surgeon experience and improved technology are associated with a significant reduction in complications. Most complications are predictable and largely preventable.
