Comparing Femtosecond Laser Assisted Cataract Surgery Before and After Phakic Intraocular Lens Removal

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1 SURGICAL TECHNIQUE Comparing Femtosecond Laser Assisted Cataract Surgery Before and After Phakic Intraocular Lens Removal Tim Schultz, MD, FEBO; Luca Schwarzenbacher, MD; H. Burkhard Dick, MD, PhD ABSTRACT PURPOSE: To investigate two approaches for femtosecond laser assisted cataract surgery (FLACS) in patients with phakic intraocular lenses (IOLs). METHODS: Anterior capsulotomy and lens fragmentation were performed with an image-guided femtosecond laser. Laser treatment was performed under sterile conditions prior to (technique 1, 5 cases) or after (technique 2, 5 cases) phakic IOL explantation. RESULTS: In technique 1, gas accumulated between the phakic IOL and the anterior capsule. In 2 (40%) of these cases, an anterior capsule tear occurred during phacoemulsification. In both cases, no anterior vitrectomy was necessary and the IOL was implanted into the capsular bag. In technique 2, no anterior capsule tears or other complications occurred. CONCLUSIONS: Laser treatment prior to phakic IOL explantation has a risk for anterior capsule tears. Potentially, the laser beam is deflected by the optic of the phakic IOL and gas between the anterior capsule and the phakic IOL induces radial forces. [J Refract Surg. 2018;34(5): ] P hakic intraocular lenses (IOLs) offer an evidencebased and viable approach for surgical correction of moderate to higher levels of refractive errors. 1 Advantages include decent refractive predictability and refractive correction without loss of accommodation. 2,3 The main reason for phakic IOL explantation is cataract formation, which is significantly accelerated after phakic IOL implantation. 2-4 Patients who were treated with phakic IOL surgery are often younger and healthier than patients who had routine cataract surgery with high demanding claims. Nonetheless, a bilentectomy including an explantation of the phakic IOL and crystalline lens can cause serious complications. 5 Femtosecond laser assisted cataract surgery (FLACS) presents a novel and promising tool in cataract surgery and potentially also in bilentectomy surgeries. In these cases, capsulotomy and lens fragmentation can be performed with the assistance of a laser. We report our experiences with FLACS in eyes after phakic IOL implantation with two different surgical techniques. PATIENTS AND METHODS Surgical Technique Between 2012 and 2016, 10 cases were included in this prospective case series at Ruhr University Eye Hospital, Bochum, Germany. An informed consent was obtained from all patients and the tenets of the Declaration of Helsinki were observed. Institutional review board approval was obtained. Eight of the cases were anterior chamber iris-fixated phakic IOLs and 2 of the cases were posterior chamber sulcus-supported phakic IOLs. The mean age of the patients was 53.3 ± 8.9 years (range: 41 to 72 years). The mean time between implantation and explantation was 11.9 ± 2.6 years (range: 7 to 16 years). Preoperatively, the pupil was dilated with tropicamide and phenylephrine eye drops, instilled three times within 1 hour. From Ruhr University Eye Hospital, Bochum, Germany (TS, HBD); and University Eye Hospital Vienna, Vienna, Austria (LS). Submitted: November 29, 2017; Accepted: February 21, 2018 The authors have no financial or proprietary interest in the materials presented herein. Correspondence: Tim Schultz, MD, FEBO, Ruhr University Eye Hospital, In der Schornau 23-25, Bochum, Germany. tim.schultz@kk-bochum.de doi: / x Journal of Refractive Surgery Vol. 34, No. 5,

2 Figure 1. Three-dimensional spectral-domain optical coherence tomography scan of the anterior chamber with iris-fixated phakic intraocular lens in place. In all cases, anterior capsulotomy and optional lens fragmentation were performed with an image-guided femtosecond laser (Catalys Precision Laser System; Johnson & Johnson, New Brunswick, NJ). The integrated threedimensional spectral-domain optical coherence tomography (SD-OCT) was used to visualize the phakic IOL and to position the treatment zones. All surgeries were performed by the same surgeon (HBD). To ensure sterility, the laser system was installed in the sterile operating room next to the surgical microscope. Thus, it was possible to swivel the patient s bed between the laser and the microscope. To achieve more reliable results, the same technique was used independent of the explanted phakic IOL type. The following two techniques were used during surgery. Technique 1 In technique 1, laser treatment was performed prior to phakic IOL explantation. The suction ring of the fluidfilled non-applanating patient interface was placed on the eye and filled with balanced salt solution (BSS; Alcon Laboratories, Inc., Fort Worth, TX). After the anterior segment of the eye was visualized by the integrated three-dimensional SD-OCT, treatment and safety zones were adjusted individually (Figure 1). A capsulotomy (pulse energy: 4 µj, incision depth: 600 µm) was created through the optic of the phakic IOL and lens fragmentation was performed. Care was taken that the treatment zone did not interfere with the optic rim. After vacuum release, the patient was rotated under the operating microscope (Figure 2). Depending on the phakic IOL type, two corneal side-port incisions were manually created in the direction of the enclavation of the phakic IOL. Next, a scleral tunnel was created at the 12-o clock position and the anterior chamber was stabilized with ophthalmic viscosurgical device (OVD). The phakic IOL was explanted carefully to avoid flattening of the anterior chamber. Then, the anterior chamber was Figure 2. Surgical microscope view after laser treatment through an irisfixated intraocular lens. Gas can be seen between the anterior capsule and phakic intraocular lens. again filled with OVD and the scleral tunnel was sutured with nylon (7-0) if necessary for secure watertight wound closure. A 2.75-mm clear corneal incision was manually made at the temporal position and the dimple-down maneuver was performed to confirm a free-floating capsulotomy. After hydrodissection and lens rotation, the softened nucleus was aspirated with the phacoemulsification device (Stellaris; Bausch & Lomb, Rochester, NY). Residual cortex was removed bimanually with irrigation/ aspiration. The capsular bag was stabilized with OVD and a foldable IOL was implanted into the capsular bag. Finally, the incisions were hydrated watertight with balanced salt solution. The patients were treated with topical ofloxacin and dexamethasone eye drops four times a day. Technique 2 In technique 2, the laser treatment was performed after phakic IOL explantation. Depending on the phakic IOL type, corneal side-port incisions were made in the direction of the enclavation of the phakic IOL and the anterior chamber was stabilized with OVD. A scleral tunnel was made and the phakic IOL was cut into pieces or was explanted en bloc. The size of the scleral tunnel can be adapted to the size of the optic of the phakic IOL and was sutured, if necessary, for secure watertight wound closure. Bimanual irrigation/aspiration was used for OVD removal. Next, the incisions were hydrated with balanced salt solution and the suction ring of the sterile personal interface was positioned 344 Copyright SLACK Incorporated

3 TABLE 1 Clinical Patient Data Case Group Age (y) Phakic IOL Type (Optic ø) Capsulotomy Size (mm) Anterior Capsule Tear 1 Laser before explantation (technique 1) 43 Iris fixated (6 mm) 4.7 Radial tear 2 Laser before explantation (technique 1) 71 Iris fixated (6 mm) 4.6 No 3 Laser before explantation (technique 1) 71 Iris fixated (6 mm) 4.9 No 4 Laser before explantation (technique 1) 39 ICL 4.8 Returned tear 5 Laser before explantation (technique 1) 55 Iris fixated (6 mm) 5 No 6 Laser after explantation (technique 2) 49 Iris fixated (6 mm) 4.9 No 7 Laser after explantation (technique 2) 57 Iris fixated (6 mm) 5 No 8 Laser after explantation (technique 2) 63 ICL 5 No 9 Laser after explantation (technique 2) 54 Iris fixated (6 mm) 4.6 No 10 Laser after explantation (technique 2) 54 Iris fixated (6 mm) 4.6 No IOL = intraocular lens; ICL = Visian ICL; STAAR Surgical Company, Monrovia, CA peripherally to the scleral tunnel. After visualization of the anterior segment, the position of the treatment zones was confirmed. An anterior capsulotomy (pulse energy: 4 µj, incision depth: 600 µm) was created, followed by fragmentation of the lens (Figure A, available in the online version of this article). After laser treatment, the patients were again rotated under the operating microscope and a 2.75-mm clear corneal incision was created. The anterior chamber was again filled with OVD and the dimple-down maneuver was performed. The nucleus was aspirated with the phacoemulsification handpiece and bimanual irrigation/aspiration was used for cortex aspiration. Finally, OVD was injected and a foldable IOL was implanted. The OVD was removed with irrigation/aspiration and the incisions were hydrated with balanced salt solution. The patients were treated with topical ofloxacin and dexamethasone eye drops four times a day. RESULTS Technique 1 was performed in 5 cases (Table 1). In all cases, it was possible to dock the patient to the laser system and the system was able to visualize the anterior segment of the eye. No suction loss occurred. In case 4, the phakic IOL (Visian ICL; STAAR Surgical Company, Monrovia, CA) showed an upside down position. The other phakic IOLs showed a regular position. It was possible to position the treatment zones and initiate the treatment in all cases. During lens fragmentation, gas gathered in all cases between the phakic IOL and the anterior capsule. In one case, an anterior capsule tear occurred during phacoemulsification (Figure B, available in the online version of this article). In a second case, a tear did not extend posteriorly. In both cases, no vitreous loss occurred and no anterior vitrectomy was necessary. The visual acuity increased Journal of Refractive Surgery Vol. 34, No. 5, 2018 after surgery in all cases and postoperative complications (corneal decompensation, infection or macular edema) did not occur in any cases. Technique 2 was performed in 5 cases. In all cases, it was possible to remove the phakic IOL without complications and hydrate the incision afterward. No flattening of the anterior chamber occurred during the docking and the laser system was able to visualize the anterior segment. In all cases, the surfaces were automatically correctly identified by the laser software. No radial tears occurred during the following steps of the procedure. The visual acuity increased after surgery in all cases of this technique and there were no postoperative complications (corneal decompensation, infection or macula edema) in any cases. DISCUSSION The development of cataract is a common complication after phakic IOL implantation. 6 FLACS presents a novel and advantageous tool in cataract surgery that potentially can be combined with phakic IOL explantation. Previous studies showed that anterior capsulotomies can be performed more precisely and the application of ultrasound energy can be lowered in FLACS. 7,8 Due to the high demands of young patients after phakic IOL implantation, the criteria for explantation should be strict and require the best surgical technique. 5 Patients who have phakic IOL implantation often have a reduced endothelial cell count and can potentially benefit from the laser treatment. 9,10 In this case series, we compared two different surgical approaches to perform FLACS in patients with a phakic IOL. No complications occurred when the laser treatment was performed after phakic IOL removal and before commencing FLACS treatment (technique 2). Furthermore, it was possible to resolve posterior synechia and center the capsulotomy on the capsular bag. 345

4 In comparison, an anterior capsule tear was seen in 2 of 5 cases (40%) when the laser treatment was performed through the optic of the phakic IOL. In these cases, several different factors might reduce the cut quality of the capsulotomy. Potentially, the laser beam is defocused by the rim of the phakic IOL optic. Histologically, misplaced laser spots seem to be the main reason for radial tears. 11 Also, the centration of the capsulotomy is limited because it depends on the potentially decentered optic of the phakic IOL. Furthermore, changes in anterior chamber depth might induce uncontrolled force on the capsulotomy rim and increase the risk of radial tears. Additionally, the gas between the phakic IOL and anterior capsule can block the laser during fragmentation and induce uncontrolled force on the rim of the capsulotomy. However, it must be noted that the IOL was implanted upside down in one case. This may have further worsened the cut quality. In comparison, no capsule complications occurred if the laser treatment was performed after phakic IOL explanation. To guarantee sterility for this technique, the laser system has to be positioned in the operating room. Furthermore, the screen and the buttons of the laser system have to be covered sterile. Previous studies found that docking was possible after opening the eye without complications using the non-applanating patient interface. 12 However, flattening of the anterior chamber can theoretically happen and injure different tissues. Centration of the capsulotomy can also be problematic due to the potentially unnatural position and shape of the pupil. The scanned capsule function is also potentially incorrect due to the alterations of the anterior capsule. In comparison to manual surgery, the use of the laser system might be time-consuming and associated with unexpected pupil constriction. Laser treatment was performed prior to phakic IOL explantation in recent studies with no complications 13,14 Diakonis et al. 14 treated a patient after phakic IOL implantation in both eyes. Various laser settings were changed to improve the cut quality and reduce the gas development; specifically, the depth of the capsulotomy, the vertical spot spacing and the anterior and posterior safety margins were increased. However, only one patient with one type of phakic IOL was treated. With these settings, the laser beam can still be blocked by the optic of the phakic IOL and a small amount of gas might influence the cut quality if the space between the phakic IOL and the crystalline lens is small. Based on our findings, we recommend explanting the phakic IOL before the laser treatment is performed. However, multicenter trials with controlled groups, updated settings, and larger patient numbers are necessary to confirm these findings. We do not recommend performing a laser lens treatment through a phakic IOL. Better results can be achieved if the laser treatment is performed after phakic IOL explanation. AUTHOR CONTRIBUTIONS Study concept and design (TS, LS, HBD); data collection (TS, LS, HBD); analysis and interpretation of data (TS, LS, HBD); writing the manuscript (TS, LS); critical revision of the manuscript (TS, HBD); statistical expertise (LS, HBD); supervision (HBD) REFERENCES 1. Barsam A, Allan BD. Excimer laser refractive surgery versus phakic intraocular lenses for the correction of moderate to high myopia. Cochrane Database Syst Rev. 2014:CD Espandar L, Meyer JJ, Moshirfar M. Phakic intraocular lenses. Curr Opin Ophthalmol. 2008;19: Alió JL, Toffaha BT, Peña-Garcia P, Sádaba LM, Barraquer RI. Phakic intraocular lens explantation: causes in 240 cases. J Refract Surg. 2015;31: Alió JL, de la Hoz F, Pérez-Sántonja JJ, Ruiz-Moreno JM, Quesada JA. Phakic anterior chamber lenses for the correction of myopia: a 7-year cumulative analysis of complications in 263 cases. Ophthalmology. 1999;106: Zeng QY, Xie XL, Chen Q. Prevention and management of collagen copolymer phakic intraocular lens exchange: causes and surgical techniques. J Cataract Refract Surg. 2015;41: Khalifa YM, Moshirfar M, Mifflin MD, Kamae K, Mamalis N, Werner L. Cataract development associated with collagen copolymer posterior chamber phakic intraocular lenses: clinicopathological correlation. J Cataract Refract Surg. 2010;36: Al Harthi K, Al Shahwan S, Al Towerki A, Banerjee PP, Behrens A, Edward DP. Comparison of the anterior capsulotomy edge created by manual capsulorhexis and 2 femtosecond laser platforms: scanning electron microscopy study. J Cataract Refract Surg. 2014;40: Conrad-Hengerer I, Hengerer FH, Schultz T, Dick HB. Effect of femtosecond laser fragmentation on effective phacoemulsification time in cataract surgery. J Refract Surg. 2012;28: Conrad-Hengerer I, Al Juburi M, Schultz T, Hengerer FH, Dick HB. Corneal endothelial cell loss and corneal thickness in conventional compared with femtosecond laser-assisted cataract surgery: three-month follow-up. J Cataract Refract Surg. 2013;39: Popovic M, Campos-Moller X, Schlenker MB, Ahmed II. Efficacy and safety of femtosecond laser-assisted cataract surgery compared with manual cataract surgery: a meta-analysis of eyes. Ophthalmology. 2016;123: Schultz T, Joachim SC, Tischoff I, Dick HB. Histologic evaluation of in vivo femtosecond laser-generated capsulotomies reveals a potential cause for radial capsular tears. Eur J Ophthalmol. 2015;25: Conrad-Hengerer I, Hengerer FH, Schultz T, Dick HB. Femtosecond laser-assisted cataract surgery in eyes with a small pupil. J Cataract Refract Surg. 2013;39: Kaur M, Sahu S, Sharma N, Titiyal JS. Femtosecond laser-assisted cataract surgery in phakic intraocular lens with cataract. 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5 Figure A. Laser treatment performed after phakic intraocular lens explantation. Due to an irregular pupil dilation, the capsulotomy was centered on the capsular bag. Figure B. Anterior capsule tear that did not run posteriorly. Laser treatment was performed through the optic of a phakic intraocular lens.