ARTICLE
Complications of femtosecond laser–assisted cataract surgery Zoltan Z. Nagy, MD, DSc, Agnes I. Takacs, MD, Tamas Filkorn, MD, Kinga Kranitz, MD, Juh Andrea Gyenes, MD, Eva asz, MD, Gabor L. Sandor, MD, Illes Kovacs, MD, PhD, Tibor Juh asz, MD, PhD, Stephen Slade, MD
PURPOSE: To analyze complications of femtosecond lasers used for cataract surgery. SETTING: Department of Ophthalmology Semmelweis University, Budapest, Hungary. DESIGN: Retrospective analysis. METHODS: Intraoperative complications of the first 100 femtosecond laser–assisted (Alcon-Lensx, Inc.) cataract surgeries were collected. Possible complications of femtosecond capsulotomies and their management were also assessed. RESULTS: The complications were as follows: suction break (2%), conjunctival redness or hemorrhage (34%), capsule tags and bridges (20%), anterior tear (4%), miosis (32%), and endothelial damage due to cut within the endothelial layer (3%). There were no cases of capsule blockage or posterior capsule tear. During the learning curve, there was no complication that would require vitrectomy. All complications occurred during the first 100 cases. CONCLUSIONS: Femtosecond laser cataract surgery had a learning curve during the first 100 cases. With cautious surgical technique, the complications can be avoided. The femtosecond laser– assisted method was efficient and safe for cataract surgery. Financial Disclosure: Drs. Nagy, T. Juhasz, and Slade are consultants to Alcon-Lensx, Inc. No other author has a financial or proprietary interest in any material or method mentioned. J Cataract Refract Surg 2014; 40:20–28 Q 2013 ASCRS and ESCRS
The number of cataract operations is continuously increasing; approximately 20 million surgeries were performed in 2010, and the number will reach 32 million by 2020.1 Accelerated lifestyles require higher visual demands than before. Surgery is being performed earlier on average because patients' needs
Submitted: January 10, 2013. Final revision submitted: August 13, 2013. Accepted: August 17, 2013. From the Department of Ophthalmology (Nagy, Takacs, Filkorn, Kranitz, Gyenes, E. Juhasz, Sandor, Kovacs), Semmelweis University, Budapest, Hungary; Department of Physics (T. Juhasz), University of Irvine, Irvine, California, and Surgivision Texas (Slade), Houston, Texas, USA. Corresponding author: Zoltan Z. Nagy, MD, DSc, Department of Ophthalmology, Semmelweis University, Maria utca 39, 1085 Budapest, Hungary. E-mail: [email protected].
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and the results that they expect to obtain from surgery have been raised. On the other hand, a new generation of intraocular lenses (IOLs) has appeared, promising better and aberration-free visual quality for far and near. It has long been known that for good visual outcome, premium IOLs must have an accurate postoperative position. To achieve the advantages these new IOLs may offer to patients, a new surgical technique with better predictability and safety is required to obtain consistent postoperative results, eliminating confounding factors such as surgical experience, surgical skills, and unusual anatomic configurations of the eye that can influence the final visual outcomes.2–5 In the past few years, femtosecond laser–assisted cataract surgery has become an accepted method of surgical intervention by ophthalmologists and patients. The most important features of femtosecond laser–assisted cataract surgery are creation of precise anterior capsulotomies, liquefaction of nuclear (N) 1 and fragmentation of N2 and N3 lenses (Lens Opacities Classification System [LOCS III]6), creation of 0886-3350/$ - see front matter http://dx.doi.org/10.1016/j.jcrs.2013.08.046
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corneal wounds in any position and size, and treatment of preoperative astigmatism. Predictably sized and centered capsulotomies help keep the IOL in the right postoperative position. Also, femtosecond laser prefragmentation of the crystalline lens significantly reduces the dissipated ultrasound (US) energy during the phacoemulsification step of cataract surgery. Corneal wounds and arcuate incisions in the desired position and at the desired depth in the cornea control postoperative astigmatism more effectively. The first human femtosecond laser–assisted cataract surgery was performed in 2008 at the Department of Ophthalmology, Semmelweis University, Budapest, Hungary. After 4 years of experience, we summarize the complications that occurred during the learning period of this new method. PATIENTS AND METHODS This study evaluated eyes that had cataract surgery assisted by a femtosecond laser (Alcon-Lensx, Alcon-Lensx, Inc.) at the Department of Ophthalmology Semmelweis University, Budapest, Hungary, between August 2008 and August 2012. During this period, the alpha and later the beta instrument was introduced; this was followed by the final versions in 2011 (version 2.13 software) and 2012 (version 2.16 software). The postoperative results of the use of the femtosecond laser in cataract surgery have been published in several peer-reviewed studies.3–5,7–9 Here, the intraoperative complications occurring during the learning period are discussed. In the first prototype of the femtosecond laser system, there was no built-in optical coherence tomography (OCT) device to help identify anatomic structures of the anterior segment of the eye during cataract surgery. Therefore, meticulous preoperative assessment of anterior segment measurements was performed using A-scan US, optical biometry, or a Scheimpflug camera. The curved patient interface of the femtosecond laser system has a soft contact lens that fits the cornea. During its application, a 16 to 35 mm Hg suction force is applied to fix the eye with the patient interface. Well-centered docking is important to avoid centrally positioned corneal wound creation (Figures 1 and 2).
Figure 1. The femtosecond laser system.
Each patient had a complete ophthalmologic evaluation. Patients with previous ocular surgery, trauma, active ocular disease, poorly dilated pupils, or known zonular weakness were excluded from the first 100 cases. The cataract stage of the patients was between N2 and N4 according to the LOCS III.6
and of the anterior and posterior surfaces of the crystalline lens was determined with the integrated OCT imaging system. A 4.5 mm diameter capsulotomy was created by scanning a cylindrical pattern, and the lens was fragmented into quadrants. Proprietary energy and spot-separation parameters were used in all laser procedures. During the conventional part of the surgery, a 2.8 mm clear corneal tunnel was created with a disposable keratome (Alcon Laboratories, Inc.). The capsulotomy was removed with a capsulorhexis forceps. After hydrodissection, fragmentation, and phacoemulsification of the nucleus, aspiration of the residual cortex was performed using an Infiniti phaco machine (Alcon Laboratories, Inc). All IOLs were folded and implanted in the capsular bag with the aid of an injection cartridge through the corneal wound. After IOL implantation, the ophthalmic viscosurgical device (OVD) was removed from the anterior chamber and capsular bag by irrigation/aspiration (I/A). All incisions were left sutureless, and no hydration was used. During the first 10 days, all patients received combined dexamethasone– tobramycin eyedrops.
Surgical Technique
RESULTS
All surgeries were performed by the same surgeon (Z.Z.N.). After pupil dilation the following were applied: 1 drop of tropicamide 0.5% every 15 minutes for 3 times and topical anesthesia of proparacaine hydrochloride 0.5%. The laser was docked to the eye using the curved contact lens to applanate the cornea. The location of the cornea
During the study period, 1230 eyes were operated on with the femtosecond laser system. The system without integrated OCT was used in the first 45 cases. All complications occurred in the first 100 cases and are reported here.
Patient Evaluation
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Figure 2. The system's screen for the surgeon. Note the corneal wounds and the astigmatic incisions. In the upper right, OCT identifies the endothelial cell layer and the anterior capsule (highest and lowest point). In the lower right, OCT identifies the cut within the crystalline lens (yellow area).
Suction Break During femtosecond laser–assisted cataract surgeries, suction break occurred intraoperatively during capsulotomy creation in 2 cases (2%). Sudden suction break during the capsulotomy did not lead to further complications, and femtosecond laser treatment was continued, although the capsulotomy part of the surgery was skipped. After the patient interface was improved, suction break did not occur. Conjunctival Redness or Hemorrhage Significant conjunctival redness or hemorrhage occurred during treatment in 34 eyes (34%). As a result of the use of curved patient interfaces with lower suction force and treatment time, introduced after the first 100 cases, the incidence of this complication significantly decreased. Capsule Tags and Bridges Before introduction of the advanced software program, which compensates for the tilt of the crystalline lens, tags and bridges occurred in 20 eyes (20%) of the surgeries.
Anterior Capsule Tear An anterior capsule tear occurred in 4 eyes (4%) during the learning curve. However, in no case did the tear extend to the posterior lens capsule. Endothelial Damage The endothelial cell layer was hit and cut during capsulotomy creation in 3 highly hyperopic eyes with a shallow anterior chamber; the first laser prototype was used in these eyes. This complication was likely caused by the lack of an integrated OCT system. Despite thorough preoperative examinations, the patient interface flattened the cornea during the femtosecond laser procedure and the safety distance from the endothelium was insufficient in these eyes (Figure 3). The surgeon noticed the endothelial cut immediately and stopped the treatment. In these cases, there were no long-term visual consequences of this complication (corrected distance visual acuity 20/20 in all cases), although the endothelial incision line could be observed 1 year after surgery. With the integration of the OCT device, no further instances of this complication occurred.
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Figure 3. A femtosecond laser–created cut (1 week after surgery) in the endothelial layer due to a shallow anterior chamber and the lack of the integrated OCT. The patient had no visual problems as a result of the small partial cut.
Capsular Blockage Syndrome and Posterior Capsule Rupture No cases of capsular blockage syndrome (CBS) or posterior capsule rupture (PCR) occurred. Miosis Miosis occurred in 32 eyes (32%) after femtosecond laser pretreatment. After a combined preoperative dilating regimen (parasympatholytics and sympathomimetics) was introduced and the suction force and time during treatment was reduced, the incidence of intraoperative pupil miosis decreased to 19% (38 eyes in first 200 surgeries); no case required mechanical pupil dilation. Vitrectomy During the learning curve, no complication required vitrectomy. DISCUSSION Here, we present our experience with complications of femtosecond laser–assisted cataract surgery during the learning period. During preoperative assessment, patients should be informed that postoperative conjunctival redness or hemorrhage can be a mild complication that occurs as a result of the docking procedure and the suction force of the patient interface. Suction break can be a common intraoperative complication during the learning curve. Inadvertent movement of the patient's head or eye, improper docking, and loose conjunctiva around the limbus are reported to be the main risk factors for suction break. The surgeon requires experience to properly apply the patient interface, and close control is essential to avoid eye movement during the procedure. Precise patient interface placement and good preoperative anesthesia are the most important factors in preventing suction
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break. The palpebral fissure should be opened as much as possible with a speculum to achieve better patient interface alignment. In cases of early and multiple suction breaks, changing the patient interface is recommended. In cases of loose conjunctiva in highly myopic eyes, the conjunctiva should be pulled out with a fine pincette under the patient interface. In general, we advise using a hard headrest for patients because with a soft headrest, the head can be pushed down during insertion of the patient interface, causing suction loss. With a hard headrest, the head cannot move downward and the risk for suction loss decreases. For anesthesia, the use of topical drops is recommended so patients can follow the laser's aiming beam to attain proper centration of the patient interface. A well-centered curvilinear anterior capsulorhexis is much safer during phacoemulsification than an irregular capsulotomy or a capsulotomy with anterior tears or bridges. However, creating a well-centered curvilinear anterior capsulorhexis requires experience and surgical skills. It is not recommended to prepare a new femtosecond laser–assisted capsulotomy with a larger diameter because possible postoperative IOL tilt can occur due to improper anterior capsule overlap. Other studies report anterior capsule tearing of the capsule during phacoemulsification. In 1 study of more than 2600 surgeries,10 an anterior capsule tear was found in 0.8% of the cases. The tear spread to the posterior capsule in 40% of cases, and 20% required vitrectomy. In another study that evaluated residents' experience,11 the incidence of anterior capsule tear was 5.3%. An irregular anterior capsulorhexis was found in 9.3% of the eyes, and a posterior capsule tear with vitreous loss occurred in 6.6% of cases. Anterior capsule tear and vitreous loss occurred approximately 7 times more frequently in surgeries performed by inexperienced surgeons. Creating a precise femtosecond laser capsulotomy has several intraoperative and postoperative advantages; however, its implementation requires special attention initially. Capsule tags and bridges are usually harmless if they are noticed in time. With slow and cautious anterior capsule removal, anterior tear can be avoided despite capsule tags. In cases of capsule tags or bridges during femtosecond laser treatment, the surgeon should follow the contour of the capsulotomy with a capsulotomy forceps. When the location of the tag is reached within the capsulotomy line, the surgeon should lead the capsulorhexis outside the original cut line. In this case, the capsulotomy diameter will be somewhat larger than the original; however an anterior capsule tear can be avoided. If this procedure is not followed, a small tear might appear at the point where the laser cut line is reached again. This tear might run outside toward the periphery during hydrodissection or phacoemulsification.
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Anterior tear of the capsule is a significant complication that can lead to posterior capsule damage with possible luxation of the nucleus into the vitreous cavity. The incidence of anterior capsule tear was low in our series as a result of the surgeon's emphasis on accurately performing the surgical steps and his acknowledgment that femtosecond laser cataract surgery is a new technique with a learning curve. The crucial step is to follow the line of the femtosecond laser cut. Pulling out the entire anterior capsule with sudden movement of a capsulorhexis forceps or phacoemulsification handpiece is not recommended during the learning curve, even in eyes with seemingly free-floating capsules. Inexperienced surgeons might not see small tags in such cases. When an anterior capsule tear occurs, the surgeon should perform very gentle hydrodissection and phacoemulsification. During phacoemulsification and removal of the cortex, gentle vector forces should be exerted (minimal suction), avoiding the area of the anterior capsule tear. During IOL implantation, the leading haptic should be kept away from the tear line. A well-centered, femtosecond laser–created continuous curvilinear capsulotomy (CCC) is called a free-floating capsulotomy (type 1 capsulotomy). In some cases, there might be microadhesions; that is, an area of complete cut mixed with minute areas of adhesions (type 2 capsulotomy). In a type 3 capsulotomy, there is an incomplete treatment pattern (no visible femtosecond laser cut in the anterior capsule). In type 4, there is an irregular complete pattern (Figure 4). During the learning curve, we strongly advise following the contour of the femtosecond laser capsulotomy with a capsulorhexis forceps. The surgeon might use a cystotome needle to identify the femtosecond laser cut in the 4 quadrants. The main aim is to free the capsulotomy from every direction. Afterward, it can be easily pulled out from the anterior chamber. During the first cases, trypan blue should be used to visualize the anterior capsule. However, trypan blue makes the capsule more rigid; therefore, preserving anterior capsule integrity might be difficult. A freefloating capsulotomy can be removed using I/A of the phacoemulsification unit; however, this maneuver is recommended for experienced surgeons only. In cases of microadhesions, the surgeon should also follow the contour of the femtosecond capsulotomy. 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 (Figure 5). During the learning curve, the surgeon should observe the femtosecond laser capsulotomy carefully with high magnification under the operating microscope. The use of trypan blue might be of help during the early phase of the learning curve.
Figure 4. Femtosecond laser capsulotomy patterns.
Anterior chamber collapse during CCC creation can also lead to a radial tear. Therefore, the recommended surgical steps are as follows: Never let the anterior chamber collapse; open the paracentesis first; stabilize the anterior chamber with an OVD; after stabilizing the anterior chamber; open the primary incision; complete the capsulotomy. The surgeon should detach the microadhesion area circumferentially following the contour of the capsulotomy (Figure 6). He or she should never pull toward the center of the microadhesion area because it can cause a tag or a nick, which can lead to an anterior capsule tear that later extends toward the periphery (Figures 7 and 8). The surgeon should never amputate the microadhesion area with a capsulorhexis forceps or capsule scissors because this can cause anterior capsule irregularity and vulnerability. For an incomplete treatment pattern, a circumferential pull is the recommended method (Figure 9). The
Figure 5. Signs of capsule attachments. Note the absence of a gutter and the trapped bubble under the capsulotomy.
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Figure 6. Managing type 2 microadhesions. As with a standard capsulorhexis, detach the type 1 capsulotomy circumferentially.
Figure 7. To manage type 2 microadhesions, do not pull the capsulotomy radially; always pull outward.
pulling force should be applied outward from the original femtosecond laser capsulotomy line (Figure 10), creating a small external notch with a smooth edge (Figure 11). Tearing inward can result in a nick in the peripheral capsule that could lead to a tear (Figure 12). In this case, during the rest of the procedure, the surgeon should be careful not to exert force on the capsule during phacoemulsification, I/A, and posterior chamber IOL (PC IOL) implantation. An irregular complete capsulotomy pattern can be caused by inadvertent and unexpected movement of the patient's eye or the patient interface during femtosecond laser capsulotomy creation. This type of irregular capsulotomy is usually not associated with a tear as long as no stress was applied in this area (Figure 13). For this reason, the surgeon must be very careful during phacoemulsification, I/A, and PC IOL insertion, steps that are also taken when the treatment pattern is incomplete. After PC IOL implantation, the surgeon
may detach the inner tag with a capsulotomy forceps or leave it as is (Figure 14). Capsular blockage syndrome with consecutive PCR is a serious complication of femtosecond laser–assisted cataract surgery. During femtosecond laser treatment of the crystalline lens, intralenticular gas bubbles are formed due to excessive energy dissipation in the lens material. After capsulotomy, the gas bubbles tend to move toward the anterior chamber. The first cases of CBS were reported in 2011 by Roberts et al.12 To prevent CBS, the capsulotomy must be performed without tags or bridges and hydrodissection has to be gentle; the use of large-diameter cannulas and a high-speed water jet under the anterior capsule should be avoided. At the beginning of the hydrodissection, the surgeon should gently press the nucleus down and move it slowly up and down. The rock 'n roll technique is advised to avoid this rare, but serious complication. This rock 'n roll technique allows air bubbles to leave the crystalline lens. When the gas
Figure 8. Radial pulling can cause a tag or a nick, leading to anterior capsule tear.
Figure 9. Managing type 3 capsulotomy (incomplete treatment pattern). As with a standard CCC, circumferentially tear the area of no treatment.
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Figure 10. Managing type 3 capsulotomy (incomplete treatment pattern). Pull circumferentially and possibly outward. In a case like this, it is better to tear outside.
Figure 11. Managing type 3 capsulotomy (incomplete treatment pattern). An external notch might be the consequence of pulling outward, but there is no anterior tear.
bubble leaves the intralenticular plane toward the anterior chamber or leaves the eye completely, there is no further danger of CBS or PCR. Gas-bubble formation can eventually be useful, helping the surgeon separate the nucleus and the epinucleus. Some surgeons do not use hydrodissection before lens sculpting. However, hydrodissection is mandatory in cases of soft or very dense lenses. In eyes with a soft lens or dense cataract, the risk for damaging the posterior capsule during I/A increases without this step. In cases of medium-hard crystalline lenses, hydrodissection can be omitted, but not during the learning curve. Femtosecond lasers create shockwaves that might affect the surrounding tissue in a 1.0 mm area. With a 5.0 mm diameter capsulotomy, the width of the pupil should be at least 6.5 mm. With a 4.5 mm diameter capsulotomy, a 6.0 mm pupil diameter is sufficient. The larger the pupil, the lower the chance of the laser shockwave hitting the pupillary margin. In addition to the shockwave, the mechanical effect of the patient
interface might cause miosis. Therefore, pupil dilation should start earlier than usual (1 hour before). More frequent instillation of mydriatics (mainly a combination of parasympatholytics and sympathomimetics) and application of nonsteroidal antiinflammatory drops are advised preoperatively to prevent intraoperative miosis. Hitting the pupil margin can cause further miosis and increase the amount of inflammatory material and the postoperative fibrin inflammatory reaction. Highly myopic eyes and eyes with pseudoexfoliation syndrome are prone to a miotic reaction after femtosecond laser treatment. Intracameral epinephrine usually helps prevent this. Damage to the endothelial layer can be avoided using the newest software of the Alcon-Lensx laser system. The femtosecond laser provides a real-time high-definition OCT image to help with docking and surgical pattern location. The optical path of the integrated OCT device corresponds to the laser beam. It provides a detailed map of the whole anterior segment
Figure 12. Managing type 3 capsulotomy (incomplete treatment pattern). Pulling inward might produce a nick, leading to a tear.
Figure 13. Managing type 4 capsulotomy. This irregular complete capsulotomy pattern can be left alone to avoid stress during surgery.
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Figure 14. Managing type 4 capsulotomy (irregular complete capsulotomy pattern). At the end of the surgery, surgeon may grab and detach the inner tag with a circumferential hand movement under OVD; however, the inner tag can also be left alone.
up to the posterior capsule of the crystalline lens; it also assesses lens density. An endothelial cut should be considered a serious complication of femtosecond laser pretreatment. With the aid of the integrated OCT system, the surgeon can avoid endothelial damage. Highly hyperopic eyes require closer attention and thoughtful preoperative anterior segment assessment. The surgeon has the opportunity to adjust the automatic treatment parameters, such as the position and depth of the capsulotomy, lens fragmentation cuts, and corneal incisions. The OCT measurements combine circular and linear scans with the goal of providing more precise information about the thickness and tilt of the crystalline lens. As was stated, proper docking is a crucial step in femtosecond laser treatment. Good centration of the patient interface prevents crystalline lens tilt and allows the application of the femtosecond laser's automatic nomograms. In most cases, no further adjustment of the treatment parameters is necessary. However, in cases of severe crystalline lens tilt, significant modification of the femtosecond laser treatment map might be necessary to ensure the safety of the procedure. Our further experience shows that the crystalline lens tilt compensation function has limits. In cases of lens subluxation, such as in Marfan syndrome or traumatic loose zonular fibers, capsular tags can occur despite all efforts to avoid them. However, the possibility of creating a CCC in cases of subluxated crystalline lenses is an advantage of the femtosecond platform. During corneal wound creation with the femtosecond laser system, if the wound is too central, it can cause surgically induced astigmatism. However, if the wound is too peripheral, it cannot be opened because the conjunctiva can block the femtosecond laser beam.
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Results in the first published study of complications of femtosecond laser–assisted cataract surgery by Bali et al.13 are in accordance with our experiences. In that study, 4 surgeons report that in the first 200 eyes, surgery suction break occurred in 2.5% and miosis in 9.5% of eyes after the femtosecond laser pretreatment. There were small anterior tags in 10.5% of eyes and a freefloating capsulotomy in 17.5% of eyes. In 13.6% of the laser-created wounds, a keratome was needed to enter the anterior chamber. Anterior radial tears were found in 4.0% of eyes, PCR in 3.5%, and a dropped nucleus in 2.0%. We agree with Roberts et al.14 and Sutton et al.15 that greater surgeon experience and improved technology are associated with a significant reduction in complications. Most complications are predictable and largely preventable; therefore, increased surgical vigilance is needed during the learning curve period. By following the recommendations given here and acknowledging that femtosecond laser–assisted cataract surgery has a learning curve and that some adjustments are required during capsulotomy, lens fragmentation, and wound creation, surgeons might achieve the maximum benefits to patients using femtosecond laser technology. WHAT WAS KNOWN Femtosecond laser–assisted cataract surgery has several advantages. Corneal wounds and arcuate incisions in the desired position and depth in the cornea make the control of postoperative astigmatism much more effective. WHAT THIS PAPER ADDS Femtosecond laser capsulotomy in highly hyperopic eyes is not safe in some cases. Without the integrated OCT, endothelial cuts can be caused with long-term consequences. The most significant complications usually occur during the first 100 femtosecond laser–assisted cataract surgeries. Complications, except endothelial cut, were similar to those reported previously. With cautious surgical technique and following the stated recommendations, intraoperative complications can be avoided.
REFERENCES 1. World Health Organization. Vision 2020. The Right to Sight. Global Initiative for the Elimination of Avoidable Blindness; Action Plan 2006–2011. Geneva, Switzerland, WHO, 2007; Available at: http://www.who.int/blindness/Vision2020_report.pdf. Accessed October 2, 2013
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€hren J, Kohnen T. Tilt and decentration of 2. Baumeister M, Bu spherical and aspheric intraocular lenses: effect on higherorder aberrations. J Cataract Refract Surg 2009; 35:1006–1012 nitz K, Takacs AI, Miha ltz K, Kova cs I, Knorz MC. 3. Nagy ZZ, Kra Comparison of intraocular lens decentration parameters after femtosecond and manual capsulotomies. J Refract Surg 2011; 27:564–569 nitz K, Takacs A, Miha ltz K, Kova cs I, Knorz MC, Nagy ZZ. 4. Kra Femtosecond laser capsulotomy and manual continuous curvilinear capsulorrhexis parameters and their effects on intraocular lens centration. J Refract Surg 2011; 27:558–563 Kra ltz K, Knorz MC, Alio JL, Taka cs AI, nitz K, Kova cs I, 5. Miha Nagy ZZ. Internal aberration and optical quality after femtosecond laser anterior capsulotomy in cataract surgery. J Refract Surg 2011; 27:711–716 6. Chylack LT Jr, Wolfe JK, Singer DM, Leske MC, Bullimore MA, Bailey IL, Friend J, McCarthy D, Wu S-Y; for the Longitudinal Study of Cataract Study Group. The Lens Opacities Classification System III. Arch Ophthalmol 1993; 111:831–836 7. Nagy Z, Takacs A, Filkorn T, Sarayba M. Initial clinical evaluation of intraocular femtosecond laser in cataract surgery. J Refract Surg 2009; 25:1053–1060 Filkorn T, Nagy ZZ. ltz K, Kova cs I, Taka cs A, 8. Ecsedy M, Miha Effect of femtosecond laser cataract surgery on the macula. J Refract Surg 2011; 27:717–722
cs AI, Kova cs I, Miha ltz K, Filkorn T, Knorz MC, Nagy ZZ. 9. Taka Central corneal volume and endothelial cell count following femtosecond laser-assisted refractive cataract surgery compared to conventional phacoemulsification. J Refract Surg 2012; 28:387–391 10. Marques FF, Marques DM, Osher RH, Osher JM. Fate of anterior capsule tears during cataract surgery. J Cataract Refract Surg 2006; 32:1638–1642 € Devranog € _ Sarıcı A, Artunay O, lu K, Akar Y, €cel I, 11. Unal M, Yu Altın M. Phacoemulsification with topical anesthesia: resident experience. J Cataract Refract Surg 2006; 32:1361–1365 12. Roberts TV, Sutton G, Lawless MA, Jindal-Bali S, Hodge C. Capsular block syndrome associated with femtosecond laserassisted cataract surgery. J Cataract Refract Surg 2011; 37:2068–2070 13. Bali SJ, Hodge C, Lawless M, Roberts TV, Sutton G. Early experience with femtosecond laser for cataract surgery. Ophthalmology 2012; 119:891–899 14. Roberts TV, Lawless M, Bali SJ, Hodge C, Sutton G. Surgical outcomes and safety of femtosecond laser cataract surgery; a prospective study of 1500 consecutive cases. Ophthalmology 2013; 120:227–233 15. Sutton G, Bali SJ, Hodge C. Femtosecond cataract surgery: transitioning to laser cataract. Curr Opin Ophthalmol 2013; 24:3–8
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Complications of femtosecond laser–assisted cataract surgery Zoltan Z. Nagy, MD, DSc, Agnes I. Takacs, MD, Tamas Filkorn, MD, Kinga Kranitz, MD, Juh Andrea Gyenes, MD, Eva asz, MD, Gabor L. Sandor, MD, Illes Kovacs, MD, PhD, Tibor Juh asz, MD, PhD, Stephen Slade, MD
PURPOSE: To analyze complications of femtosecond lasers used for cataract surgery. SETTING: Department of Ophthalmology Semmelweis University, Budapest, Hungary. DESIGN: Retrospective analysis. METHODS: Intraoperative complications of the first 100 femtosecond laser–assisted (Alcon-Lensx, Inc.) cataract surgeries were collected. Possible complications of femtosecond capsulotomies and their management were also assessed. RESULTS: The complications were as follows: suction break (2%), conjunctival redness or hemorrhage (34%), capsule tags and bridges (20%), anterior tear (4%), miosis (32%), and endothelial damage due to cut within the endothelial layer (3%). There were no cases of capsule blockage or posterior capsule tear. During the learning curve, there was no complication that would require vitrectomy. All complications occurred during the first 100 cases. CONCLUSIONS: Femtosecond laser cataract surgery had a learning curve during the first 100 cases. With cautious surgical technique, the complications can be avoided. The femtosecond laser– assisted method was efficient and safe for cataract surgery. Financial Disclosure: Drs. Nagy, T. Juhasz, and Slade are consultants to Alcon-Lensx, Inc. No other author has a financial or proprietary interest in any material or method mentioned. J Cataract Refract Surg 2014; 40:20–28 Q 2013 ASCRS and ESCRS
The number of cataract operations is continuously increasing; approximately 20 million surgeries were performed in 2010, and the number will reach 32 million by 2020.1 Accelerated lifestyles require higher visual demands than before. Surgery is being performed earlier on average because patients' needs
Submitted: January 10, 2013. Final revision submitted: August 13, 2013. Accepted: August 17, 2013. From the Department of Ophthalmology (Nagy, Takacs, Filkorn, Kranitz, Gyenes, E. Juhasz, Sandor, Kovacs), Semmelweis University, Budapest, Hungary; Department of Physics (T. Juhasz), University of Irvine, Irvine, California, and Surgivision Texas (Slade), Houston, Texas, USA. Corresponding author: Zoltan Z. Nagy, MD, DSc, Department of Ophthalmology, Semmelweis University, Maria utca 39, 1085 Budapest, Hungary. E-mail: [email protected].
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and the results that they expect to obtain from surgery have been raised. On the other hand, a new generation of intraocular lenses (IOLs) has appeared, promising better and aberration-free visual quality for far and near. It has long been known that for good visual outcome, premium IOLs must have an accurate postoperative position. To achieve the advantages these new IOLs may offer to patients, a new surgical technique with better predictability and safety is required to obtain consistent postoperative results, eliminating confounding factors such as surgical experience, surgical skills, and unusual anatomic configurations of the eye that can influence the final visual outcomes.2–5 In the past few years, femtosecond laser–assisted cataract surgery has become an accepted method of surgical intervention by ophthalmologists and patients. The most important features of femtosecond laser–assisted cataract surgery are creation of precise anterior capsulotomies, liquefaction of nuclear (N) 1 and fragmentation of N2 and N3 lenses (Lens Opacities Classification System [LOCS III]6), creation of 0886-3350/$ - see front matter http://dx.doi.org/10.1016/j.jcrs.2013.08.046
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corneal wounds in any position and size, and treatment of preoperative astigmatism. Predictably sized and centered capsulotomies help keep the IOL in the right postoperative position. Also, femtosecond laser prefragmentation of the crystalline lens significantly reduces the dissipated ultrasound (US) energy during the phacoemulsification step of cataract surgery. Corneal wounds and arcuate incisions in the desired position and at the desired depth in the cornea control postoperative astigmatism more effectively. The first human femtosecond laser–assisted cataract surgery was performed in 2008 at the Department of Ophthalmology, Semmelweis University, Budapest, Hungary. After 4 years of experience, we summarize the complications that occurred during the learning period of this new method. PATIENTS AND METHODS This study evaluated eyes that had cataract surgery assisted by a femtosecond laser (Alcon-Lensx, Alcon-Lensx, Inc.) at the Department of Ophthalmology Semmelweis University, Budapest, Hungary, between August 2008 and August 2012. During this period, the alpha and later the beta instrument was introduced; this was followed by the final versions in 2011 (version 2.13 software) and 2012 (version 2.16 software). The postoperative results of the use of the femtosecond laser in cataract surgery have been published in several peer-reviewed studies.3–5,7–9 Here, the intraoperative complications occurring during the learning period are discussed. In the first prototype of the femtosecond laser system, there was no built-in optical coherence tomography (OCT) device to help identify anatomic structures of the anterior segment of the eye during cataract surgery. Therefore, meticulous preoperative assessment of anterior segment measurements was performed using A-scan US, optical biometry, or a Scheimpflug camera. The curved patient interface of the femtosecond laser system has a soft contact lens that fits the cornea. During its application, a 16 to 35 mm Hg suction force is applied to fix the eye with the patient interface. Well-centered docking is important to avoid centrally positioned corneal wound creation (Figures 1 and 2).
Figure 1. The femtosecond laser system.
Each patient had a complete ophthalmologic evaluation. Patients with previous ocular surgery, trauma, active ocular disease, poorly dilated pupils, or known zonular weakness were excluded from the first 100 cases. The cataract stage of the patients was between N2 and N4 according to the LOCS III.6
and of the anterior and posterior surfaces of the crystalline lens was determined with the integrated OCT imaging system. A 4.5 mm diameter capsulotomy was created by scanning a cylindrical pattern, and the lens was fragmented into quadrants. Proprietary energy and spot-separation parameters were used in all laser procedures. During the conventional part of the surgery, a 2.8 mm clear corneal tunnel was created with a disposable keratome (Alcon Laboratories, Inc.). The capsulotomy was removed with a capsulorhexis forceps. After hydrodissection, fragmentation, and phacoemulsification of the nucleus, aspiration of the residual cortex was performed using an Infiniti phaco machine (Alcon Laboratories, Inc). All IOLs were folded and implanted in the capsular bag with the aid of an injection cartridge through the corneal wound. After IOL implantation, the ophthalmic viscosurgical device (OVD) was removed from the anterior chamber and capsular bag by irrigation/aspiration (I/A). All incisions were left sutureless, and no hydration was used. During the first 10 days, all patients received combined dexamethasone– tobramycin eyedrops.
Surgical Technique
RESULTS
All surgeries were performed by the same surgeon (Z.Z.N.). After pupil dilation the following were applied: 1 drop of tropicamide 0.5% every 15 minutes for 3 times and topical anesthesia of proparacaine hydrochloride 0.5%. The laser was docked to the eye using the curved contact lens to applanate the cornea. The location of the cornea
During the study period, 1230 eyes were operated on with the femtosecond laser system. The system without integrated OCT was used in the first 45 cases. All complications occurred in the first 100 cases and are reported here.
Patient Evaluation
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Figure 2. The system's screen for the surgeon. Note the corneal wounds and the astigmatic incisions. In the upper right, OCT identifies the endothelial cell layer and the anterior capsule (highest and lowest point). In the lower right, OCT identifies the cut within the crystalline lens (yellow area).
Suction Break During femtosecond laser–assisted cataract surgeries, suction break occurred intraoperatively during capsulotomy creation in 2 cases (2%). Sudden suction break during the capsulotomy did not lead to further complications, and femtosecond laser treatment was continued, although the capsulotomy part of the surgery was skipped. After the patient interface was improved, suction break did not occur. Conjunctival Redness or Hemorrhage Significant conjunctival redness or hemorrhage occurred during treatment in 34 eyes (34%). As a result of the use of curved patient interfaces with lower suction force and treatment time, introduced after the first 100 cases, the incidence of this complication significantly decreased. Capsule Tags and Bridges Before introduction of the advanced software program, which compensates for the tilt of the crystalline lens, tags and bridges occurred in 20 eyes (20%) of the surgeries.
Anterior Capsule Tear An anterior capsule tear occurred in 4 eyes (4%) during the learning curve. However, in no case did the tear extend to the posterior lens capsule. Endothelial Damage The endothelial cell layer was hit and cut during capsulotomy creation in 3 highly hyperopic eyes with a shallow anterior chamber; the first laser prototype was used in these eyes. This complication was likely caused by the lack of an integrated OCT system. Despite thorough preoperative examinations, the patient interface flattened the cornea during the femtosecond laser procedure and the safety distance from the endothelium was insufficient in these eyes (Figure 3). The surgeon noticed the endothelial cut immediately and stopped the treatment. In these cases, there were no long-term visual consequences of this complication (corrected distance visual acuity 20/20 in all cases), although the endothelial incision line could be observed 1 year after surgery. With the integration of the OCT device, no further instances of this complication occurred.
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Figure 3. A femtosecond laser–created cut (1 week after surgery) in the endothelial layer due to a shallow anterior chamber and the lack of the integrated OCT. The patient had no visual problems as a result of the small partial cut.
Capsular Blockage Syndrome and Posterior Capsule Rupture No cases of capsular blockage syndrome (CBS) or posterior capsule rupture (PCR) occurred. Miosis Miosis occurred in 32 eyes (32%) after femtosecond laser pretreatment. After a combined preoperative dilating regimen (parasympatholytics and sympathomimetics) was introduced and the suction force and time during treatment was reduced, the incidence of intraoperative pupil miosis decreased to 19% (38 eyes in first 200 surgeries); no case required mechanical pupil dilation. Vitrectomy During the learning curve, no complication required vitrectomy. DISCUSSION Here, we present our experience with complications of femtosecond laser–assisted cataract surgery during the learning period. During preoperative assessment, patients should be informed that postoperative conjunctival redness or hemorrhage can be a mild complication that occurs as a result of the docking procedure and the suction force of the patient interface. Suction break can be a common intraoperative complication during the learning curve. Inadvertent movement of the patient's head or eye, improper docking, and loose conjunctiva around the limbus are reported to be the main risk factors for suction break. The surgeon requires experience to properly apply the patient interface, and close control is essential to avoid eye movement during the procedure. Precise patient interface placement and good preoperative anesthesia are the most important factors in preventing suction
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break. The palpebral fissure should be opened as much as possible with a speculum to achieve better patient interface alignment. In cases of early and multiple suction breaks, changing the patient interface is recommended. In cases of loose conjunctiva in highly myopic eyes, the conjunctiva should be pulled out with a fine pincette under the patient interface. In general, we advise using a hard headrest for patients because with a soft headrest, the head can be pushed down during insertion of the patient interface, causing suction loss. With a hard headrest, the head cannot move downward and the risk for suction loss decreases. For anesthesia, the use of topical drops is recommended so patients can follow the laser's aiming beam to attain proper centration of the patient interface. A well-centered curvilinear anterior capsulorhexis is much safer during phacoemulsification than an irregular capsulotomy or a capsulotomy with anterior tears or bridges. However, creating a well-centered curvilinear anterior capsulorhexis requires experience and surgical skills. It is not recommended to prepare a new femtosecond laser–assisted capsulotomy with a larger diameter because possible postoperative IOL tilt can occur due to improper anterior capsule overlap. Other studies report anterior capsule tearing of the capsule during phacoemulsification. In 1 study of more than 2600 surgeries,10 an anterior capsule tear was found in 0.8% of the cases. The tear spread to the posterior capsule in 40% of cases, and 20% required vitrectomy. In another study that evaluated residents' experience,11 the incidence of anterior capsule tear was 5.3%. An irregular anterior capsulorhexis was found in 9.3% of the eyes, and a posterior capsule tear with vitreous loss occurred in 6.6% of cases. Anterior capsule tear and vitreous loss occurred approximately 7 times more frequently in surgeries performed by inexperienced surgeons. Creating a precise femtosecond laser capsulotomy has several intraoperative and postoperative advantages; however, its implementation requires special attention initially. Capsule tags and bridges are usually harmless if they are noticed in time. With slow and cautious anterior capsule removal, anterior tear can be avoided despite capsule tags. In cases of capsule tags or bridges during femtosecond laser treatment, the surgeon should follow the contour of the capsulotomy with a capsulotomy forceps. When the location of the tag is reached within the capsulotomy line, the surgeon should lead the capsulorhexis outside the original cut line. In this case, the capsulotomy diameter will be somewhat larger than the original; however an anterior capsule tear can be avoided. If this procedure is not followed, a small tear might appear at the point where the laser cut line is reached again. This tear might run outside toward the periphery during hydrodissection or phacoemulsification.
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Anterior tear of the capsule is a significant complication that can lead to posterior capsule damage with possible luxation of the nucleus into the vitreous cavity. The incidence of anterior capsule tear was low in our series as a result of the surgeon's emphasis on accurately performing the surgical steps and his acknowledgment that femtosecond laser cataract surgery is a new technique with a learning curve. The crucial step is to follow the line of the femtosecond laser cut. Pulling out the entire anterior capsule with sudden movement of a capsulorhexis forceps or phacoemulsification handpiece is not recommended during the learning curve, even in eyes with seemingly free-floating capsules. Inexperienced surgeons might not see small tags in such cases. When an anterior capsule tear occurs, the surgeon should perform very gentle hydrodissection and phacoemulsification. During phacoemulsification and removal of the cortex, gentle vector forces should be exerted (minimal suction), avoiding the area of the anterior capsule tear. During IOL implantation, the leading haptic should be kept away from the tear line. A well-centered, femtosecond laser–created continuous curvilinear capsulotomy (CCC) is called a free-floating capsulotomy (type 1 capsulotomy). In some cases, there might be microadhesions; that is, an area of complete cut mixed with minute areas of adhesions (type 2 capsulotomy). In a type 3 capsulotomy, there is an incomplete treatment pattern (no visible femtosecond laser cut in the anterior capsule). In type 4, there is an irregular complete pattern (Figure 4). During the learning curve, we strongly advise following the contour of the femtosecond laser capsulotomy with a capsulorhexis forceps. The surgeon might use a cystotome needle to identify the femtosecond laser cut in the 4 quadrants. The main aim is to free the capsulotomy from every direction. Afterward, it can be easily pulled out from the anterior chamber. During the first cases, trypan blue should be used to visualize the anterior capsule. However, trypan blue makes the capsule more rigid; therefore, preserving anterior capsule integrity might be difficult. A freefloating capsulotomy can be removed using I/A of the phacoemulsification unit; however, this maneuver is recommended for experienced surgeons only. In cases of microadhesions, the surgeon should also follow the contour of the femtosecond capsulotomy. 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 (Figure 5). During the learning curve, the surgeon should observe the femtosecond laser capsulotomy carefully with high magnification under the operating microscope. The use of trypan blue might be of help during the early phase of the learning curve.
Figure 4. Femtosecond laser capsulotomy patterns.
Anterior chamber collapse during CCC creation can also lead to a radial tear. Therefore, the recommended surgical steps are as follows: Never let the anterior chamber collapse; open the paracentesis first; stabilize the anterior chamber with an OVD; after stabilizing the anterior chamber; open the primary incision; complete the capsulotomy. The surgeon should detach the microadhesion area circumferentially following the contour of the capsulotomy (Figure 6). He or she should never pull toward the center of the microadhesion area because it can cause a tag or a nick, which can lead to an anterior capsule tear that later extends toward the periphery (Figures 7 and 8). The surgeon should never amputate the microadhesion area with a capsulorhexis forceps or capsule scissors because this can cause anterior capsule irregularity and vulnerability. For an incomplete treatment pattern, a circumferential pull is the recommended method (Figure 9). The
Figure 5. Signs of capsule attachments. Note the absence of a gutter and the trapped bubble under the capsulotomy.
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Figure 6. Managing type 2 microadhesions. As with a standard capsulorhexis, detach the type 1 capsulotomy circumferentially.
Figure 7. To manage type 2 microadhesions, do not pull the capsulotomy radially; always pull outward.
pulling force should be applied outward from the original femtosecond laser capsulotomy line (Figure 10), creating a small external notch with a smooth edge (Figure 11). Tearing inward can result in a nick in the peripheral capsule that could lead to a tear (Figure 12). In this case, during the rest of the procedure, the surgeon should be careful not to exert force on the capsule during phacoemulsification, I/A, and posterior chamber IOL (PC IOL) implantation. An irregular complete capsulotomy pattern can be caused by inadvertent and unexpected movement of the patient's eye or the patient interface during femtosecond laser capsulotomy creation. This type of irregular capsulotomy is usually not associated with a tear as long as no stress was applied in this area (Figure 13). For this reason, the surgeon must be very careful during phacoemulsification, I/A, and PC IOL insertion, steps that are also taken when the treatment pattern is incomplete. After PC IOL implantation, the surgeon
may detach the inner tag with a capsulotomy forceps or leave it as is (Figure 14). Capsular blockage syndrome with consecutive PCR is a serious complication of femtosecond laser–assisted cataract surgery. During femtosecond laser treatment of the crystalline lens, intralenticular gas bubbles are formed due to excessive energy dissipation in the lens material. After capsulotomy, the gas bubbles tend to move toward the anterior chamber. The first cases of CBS were reported in 2011 by Roberts et al.12 To prevent CBS, the capsulotomy must be performed without tags or bridges and hydrodissection has to be gentle; the use of large-diameter cannulas and a high-speed water jet under the anterior capsule should be avoided. At the beginning of the hydrodissection, the surgeon should gently press the nucleus down and move it slowly up and down. The rock 'n roll technique is advised to avoid this rare, but serious complication. This rock 'n roll technique allows air bubbles to leave the crystalline lens. When the gas
Figure 8. Radial pulling can cause a tag or a nick, leading to anterior capsule tear.
Figure 9. Managing type 3 capsulotomy (incomplete treatment pattern). As with a standard CCC, circumferentially tear the area of no treatment.
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Figure 10. Managing type 3 capsulotomy (incomplete treatment pattern). Pull circumferentially and possibly outward. In a case like this, it is better to tear outside.
Figure 11. Managing type 3 capsulotomy (incomplete treatment pattern). An external notch might be the consequence of pulling outward, but there is no anterior tear.
bubble leaves the intralenticular plane toward the anterior chamber or leaves the eye completely, there is no further danger of CBS or PCR. Gas-bubble formation can eventually be useful, helping the surgeon separate the nucleus and the epinucleus. Some surgeons do not use hydrodissection before lens sculpting. However, hydrodissection is mandatory in cases of soft or very dense lenses. In eyes with a soft lens or dense cataract, the risk for damaging the posterior capsule during I/A increases without this step. In cases of medium-hard crystalline lenses, hydrodissection can be omitted, but not during the learning curve. Femtosecond lasers create shockwaves that might affect the surrounding tissue in a 1.0 mm area. With a 5.0 mm diameter capsulotomy, the width of the pupil should be at least 6.5 mm. With a 4.5 mm diameter capsulotomy, a 6.0 mm pupil diameter is sufficient. The larger the pupil, the lower the chance of the laser shockwave hitting the pupillary margin. In addition to the shockwave, the mechanical effect of the patient
interface might cause miosis. Therefore, pupil dilation should start earlier than usual (1 hour before). More frequent instillation of mydriatics (mainly a combination of parasympatholytics and sympathomimetics) and application of nonsteroidal antiinflammatory drops are advised preoperatively to prevent intraoperative miosis. Hitting the pupil margin can cause further miosis and increase the amount of inflammatory material and the postoperative fibrin inflammatory reaction. Highly myopic eyes and eyes with pseudoexfoliation syndrome are prone to a miotic reaction after femtosecond laser treatment. Intracameral epinephrine usually helps prevent this. Damage to the endothelial layer can be avoided using the newest software of the Alcon-Lensx laser system. The femtosecond laser provides a real-time high-definition OCT image to help with docking and surgical pattern location. The optical path of the integrated OCT device corresponds to the laser beam. It provides a detailed map of the whole anterior segment
Figure 12. Managing type 3 capsulotomy (incomplete treatment pattern). Pulling inward might produce a nick, leading to a tear.
Figure 13. Managing type 4 capsulotomy. This irregular complete capsulotomy pattern can be left alone to avoid stress during surgery.
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Figure 14. Managing type 4 capsulotomy (irregular complete capsulotomy pattern). At the end of the surgery, surgeon may grab and detach the inner tag with a circumferential hand movement under OVD; however, the inner tag can also be left alone.
up to the posterior capsule of the crystalline lens; it also assesses lens density. An endothelial cut should be considered a serious complication of femtosecond laser pretreatment. With the aid of the integrated OCT system, the surgeon can avoid endothelial damage. Highly hyperopic eyes require closer attention and thoughtful preoperative anterior segment assessment. The surgeon has the opportunity to adjust the automatic treatment parameters, such as the position and depth of the capsulotomy, lens fragmentation cuts, and corneal incisions. The OCT measurements combine circular and linear scans with the goal of providing more precise information about the thickness and tilt of the crystalline lens. As was stated, proper docking is a crucial step in femtosecond laser treatment. Good centration of the patient interface prevents crystalline lens tilt and allows the application of the femtosecond laser's automatic nomograms. In most cases, no further adjustment of the treatment parameters is necessary. However, in cases of severe crystalline lens tilt, significant modification of the femtosecond laser treatment map might be necessary to ensure the safety of the procedure. Our further experience shows that the crystalline lens tilt compensation function has limits. In cases of lens subluxation, such as in Marfan syndrome or traumatic loose zonular fibers, capsular tags can occur despite all efforts to avoid them. However, the possibility of creating a CCC in cases of subluxated crystalline lenses is an advantage of the femtosecond platform. During corneal wound creation with the femtosecond laser system, if the wound is too central, it can cause surgically induced astigmatism. However, if the wound is too peripheral, it cannot be opened because the conjunctiva can block the femtosecond laser beam.
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Results in the first published study of complications of femtosecond laser–assisted cataract surgery by Bali et al.13 are in accordance with our experiences. In that study, 4 surgeons report that in the first 200 eyes, surgery suction break occurred in 2.5% and miosis in 9.5% of eyes after the femtosecond laser pretreatment. There were small anterior tags in 10.5% of eyes and a freefloating capsulotomy in 17.5% of eyes. In 13.6% of the laser-created wounds, a keratome was needed to enter the anterior chamber. Anterior radial tears were found in 4.0% of eyes, PCR in 3.5%, and a dropped nucleus in 2.0%. We agree with Roberts et al.14 and Sutton et al.15 that greater surgeon experience and improved technology are associated with a significant reduction in complications. Most complications are predictable and largely preventable; therefore, increased surgical vigilance is needed during the learning curve period. By following the recommendations given here and acknowledging that femtosecond laser–assisted cataract surgery has a learning curve and that some adjustments are required during capsulotomy, lens fragmentation, and wound creation, surgeons might achieve the maximum benefits to patients using femtosecond laser technology. WHAT WAS KNOWN Femtosecond laser–assisted cataract surgery has several advantages. Corneal wounds and arcuate incisions in the desired position and depth in the cornea make the control of postoperative astigmatism much more effective. WHAT THIS PAPER ADDS Femtosecond laser capsulotomy in highly hyperopic eyes is not safe in some cases. Without the integrated OCT, endothelial cuts can be caused with long-term consequences. The most significant complications usually occur during the first 100 femtosecond laser–assisted cataract surgeries. Complications, except endothelial cut, were similar to those reported previously. With cautious surgical technique and following the stated recommendations, intraoperative complications can be avoided.
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€hren J, Kohnen T. Tilt and decentration of 2. Baumeister M, Bu spherical and aspheric intraocular lenses: effect on higherorder aberrations. J Cataract Refract Surg 2009; 35:1006–1012 nitz K, Takacs AI, Miha ltz K, Kova cs I, Knorz MC. 3. Nagy ZZ, Kra Comparison of intraocular lens decentration parameters after femtosecond and manual capsulotomies. J Refract Surg 2011; 27:564–569 nitz K, Takacs A, Miha ltz K, Kova cs I, Knorz MC, Nagy ZZ. 4. Kra Femtosecond laser capsulotomy and manual continuous curvilinear capsulorrhexis parameters and their effects on intraocular lens centration. J Refract Surg 2011; 27:558–563 Kra ltz K, Knorz MC, Alio JL, Taka cs AI, nitz K, Kova cs I, 5. Miha Nagy ZZ. Internal aberration and optical quality after femtosecond laser anterior capsulotomy in cataract surgery. J Refract Surg 2011; 27:711–716 6. Chylack LT Jr, Wolfe JK, Singer DM, Leske MC, Bullimore MA, Bailey IL, Friend J, McCarthy D, Wu S-Y; for the Longitudinal Study of Cataract Study Group. The Lens Opacities Classification System III. Arch Ophthalmol 1993; 111:831–836 7. Nagy Z, Takacs A, Filkorn T, Sarayba M. Initial clinical evaluation of intraocular femtosecond laser in cataract surgery. J Refract Surg 2009; 25:1053–1060 Filkorn T, Nagy ZZ. ltz K, Kova cs I, Taka cs A, 8. Ecsedy M, Miha Effect of femtosecond laser cataract surgery on the macula. J Refract Surg 2011; 27:717–722
cs AI, Kova cs I, Miha ltz K, Filkorn T, Knorz MC, Nagy ZZ. 9. Taka Central corneal volume and endothelial cell count following femtosecond laser-assisted refractive cataract surgery compared to conventional phacoemulsification. J Refract Surg 2012; 28:387–391 10. Marques FF, Marques DM, Osher RH, Osher JM. Fate of anterior capsule tears during cataract surgery. J Cataract Refract Surg 2006; 32:1638–1642 € Devranog € _ Sarıcı A, Artunay O, lu K, Akar Y, €cel I, 11. Unal M, Yu Altın M. Phacoemulsification with topical anesthesia: resident experience. J Cataract Refract Surg 2006; 32:1361–1365 12. Roberts TV, Sutton G, Lawless MA, Jindal-Bali S, Hodge C. Capsular block syndrome associated with femtosecond laserassisted cataract surgery. J Cataract Refract Surg 2011; 37:2068–2070 13. Bali SJ, Hodge C, Lawless M, Roberts TV, Sutton G. Early experience with femtosecond laser for cataract surgery. Ophthalmology 2012; 119:891–899 14. Roberts TV, Lawless M, Bali SJ, Hodge C, Sutton G. Surgical outcomes and safety of femtosecond laser cataract surgery; a prospective study of 1500 consecutive cases. Ophthalmology 2013; 120:227–233 15. Sutton G, Bali SJ, Hodge C. Femtosecond cataract surgery: transitioning to laser cataract. Curr Opin Ophthalmol 2013; 24:3–8
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