Change of Capsulotomy Over 1 Year in Femtosecond Laser-Assisted Cataract Surgery and Its Impact on Visual Quality

Transcription

1 ORIGINAL ARTICLE Change of Capsulotomy Over 1 Year in Femtosecond Laser-Assisted Cataract Surgery and Its Impact on Visual Quality Christophe Panthier, MD; Florent Costantini, MD; Jean Claude Rigal-Sastourné, MD, PhD; Antoine Brézin, MD, PhD; Chadi Mehanna, MD; Mikael Guedj, MD; Dominique Monnet, MD, PhD ABSTRACT PURPOSE: To compare the shape of the capsulotomy, its change, and its impact on visual quality over 1 year using the femtosecond laser system from the manual technique. METHODS: In this two-center cross-sectional study from May 2012 to June 2013, each patient had femtosecond laser-assisted cataract surgery in one eye (FLACS group) and conventional phacoemulsification cataract surgery in the other eye (CPCS group). An evaluation of the capsulotomy was performed using retroillumination slit-lamp photographs at 7 days, 6 months, and 1 year after surgery. Effective lens position (ELP), refractive error, and corrected distance visual acuity (CDVA) were analyzed. RESULTS: Thirty-three patients were included in the study. Diameters of capsulorhexis were more precise and deviation surfaces were lower in the FLACS group than in the CPCS group at each evaluation (P <.05). Femtosecond laser capsulotomies were less modified over time than manual continuous curvilinear capsulorhexis. No significant differences were observed for CDVA, refractive error, and ELP between groups. CONCLUSIONS: More precise capsulotomy sizing can be achieved with the femtosecond laser compared to continuous curvilinear capsulorhexis. Femtosecond laser capsulotomies are less modified over time but did not improve ELP or visual quality. [J Refract Surg. 2017;33(1):44-49] C ataract surgery is the most performed surgery in the world. Conventional phacoemulsification cataract surgery is a reliable technique. Femtosecond laserassisted cataract surgery (FLACS) is emerging as a credible alternative to the conventional technique. It provides high efficacy and safety in realizing capsulotomies. 1 Capsulorhexis is a difficult step of manual phacoemulsification even for trained surgeons. 2 A perfect circular and centered capsulorhexis could directly influence the effective lens position (ELP) and hence the refractive outcome. 3-5 Moreover, capsulotomies can change over time as a living tissue. These evolutions could explain in part the instability of refractive results in some cases. 6 Femtosecond laser surgery is presented as a technique that provides more reliable and more accurate capsulotomies than manual capsulorhexis technique with safety. 7,8 The purpose of the study was to compare the shape of the anterior capsulotomy, its change, and its potential impact on visual quality over 1 year after surgery using either the femtosecond laser system or the conventional manual technique. PATIENTS AND METHODS Patient Selection This study was a cross-sectional multicenter study conducted from May 2012 to June 2013 in two centers: Hôpital Cochin, Assistance Publique des Hôpitaux de Paris, France, and Hôpital Inter-Armée Percy, France. Thirty-three consecutive patients eligible for cataract surgery were included in our study after they gave informed consent. For all patients, one eye was randomly included in From the Department of Ophthalmology, University of Paris V, Paris, France (CP, FC, AB, CM, MG, DM); and the Department of Ophthalmology, University of Paris XI, Clamart, France (JCR-S). Submitted: February 10, 2016; Accepted: September 21, 2016 The authors have no financial or proprietary interest in the materials presented herein. Correspondence: Dominique Monnet, MD, PhD, Department of Ophthalmology, University of Paris V, René Descartes, Hôpital Cochin-Hôtel Dieu, 27 Rue du Faubourg Saint-Jacques, Paris, France. dominique.monnet@ cch.aphp.fr doi: / x Copyright SLACK Incorporated

2 the FLACS group and the other in the conventional phacoemulsification cataract surgery (CPCS) group, regardless of the side or the order of surgery. The FLACS procedures were performed from May to June There were no additional financial charges to patients for FLACS procedures. Exclusion criteria were a patient who had only one eye or poor pupillary dilation. All patients had a baseline preoperative assessment and a full preoperative examination including objective and subjective refraction, slit-lamp examination, intraocular pressure measurement, and fundus examination after pupillary dilation. Axial length and keratometry were determined using partial coherence interferometry with the IOLMaster (software version 5; Carl Zeiss Meditec, Jena, Germany) non-contact biometry device. We used the SRK-T algorithm to perform the intraocular lens (IOL) calculations and the Haigis formula to estimate the effective lens position (ELP). This study was performed with the approval of our local ethics committee and in agreement with the tenets of the Declaration of Helsinki. Surgical Procedure Standardized preoperative care protocols (preparation of the patient, disinfection, and anesthesia) were exactly the same for both groups. Four experienced surgeons performed all surgeries (including AB, DM, and JCR-S). The Victus femtosecond laser (Bausch + Lomb Company, München, Germany) was used for FLACS. The femtosecond laser was programmed to make a 5.5-mm anterior capsulotomy and nucleus fragmentation. The same surgeon had to operate on both eyes of each patient using a standardized technique. In the FLACS group, the femtosecond laser part was performed in the same operating room as the rest of the surgical procedure. In both groups, the anterior chamber was filled with sodium hyaluronate 3.0% chondroitin sulfate 4.0% (Viscoat; Alcon Laboratories, Inc., Fort Worth, TX). In the FLACS group, the capsular flap was removed with capsulorhexis forceps (Crozafon forceps; MORIA Inc., Doylestown, PA) or completed manually in cases with a non free-floating capsule. In the conventional technique, a manual anterior capsulotomy of 5.5 mm was made with the same capsulorhexis forceps. Surgery was completed in both groups using standard phacoemulsification procedures, including removal of the lens cortex and IOL implantation. Postoperative care protocols were similar in both groups, including a combination of steroids and antibiotics for 3 weeks with progressively decreasing dosage. Measures A preoperative analysis of the capsulorhexis was completed. The percentages of free-floating capsulotomy, tears, and bridging tags were measured. We defined a tear Journal of Refractive Surgery Vol. 33, No. 1, 2017 as a split in the edge of the capsulotomy and a bridging tag as an incomplete laser capsulotomy circumference. 1 All patients underwent a full examination at 7 days, 6 months, and 1 year after surgery, including uncorrected and corrected distance visual acuity and anterior and posterior segment examination. Other evaluations included photography of the capsulorhexis, measurement of the ELP with Visante optical coherence tomography (OCT) (Carl Zeiss Meditec) or a Scheimpflug imaging system (Pentacam; Oculus Optikgeräte GmbH, Wetzlar, Germany) and a wavefront analysis (L80 ARK; Luneau Visionix, Paris, France). The postoperative refractive error was estimated by comparing the observed outcomes with the theoretical target value calculated with a biometer. For the review of the capsulorhexis, a single masked operator performed the anterior segment photographs in retroillumination with a slit lamp after pupillary dilation (Canon EOS 20D and Eyecap software; Haag-Streit, Wedel, Germany). To evaluate the quality of the rhexis in terms of circularity and sizing, photographs were digitalized and analyzed by a single operator, ignoring the surgical procedure, using a professional drawing software (Covadis; Geomedia S.A.S, Brest, France). The operator selected three points on the surgical capsulorhexis. The fourth was fixed by the software to create a theoretical 5.5-mm capsulorhexis. The deviation area was defined and calculated by the measurement of the area outside and inside this theoretical capsulorhexis (Figure A, available in the online version of this article). The relative error was defined as the ratio between the deviation area and the theoretical capsulorhexis area (23.74 mm 2 for a circle with a diameter of 5.5 mm). For the analysis of ELP, the fifth generation theoretical IOL power calculation Haigis formula was used. The Haigis formula is a keratometry-independent ELP estimation method 9 that is comparable to traditional keratometrydependent methods in terms of precision. 10 The postoperative lens position was measured with a Scheimpflug imaging device (Pentacam) or with Visante OCT. To obtain the Pentacam-measured postoperative lens position, the Scheimpflug image in the horizontal meridian was displayed. A line was drawn perpendicularly from the anterior corneal vertex to the line connecting to the anterior chamber angles showed by the software. The distance from the anterior corneal surface to the lens plane on this line was defined as the postoperative lens position For the postoperative lens position measured by Visante OCT, three corneal scans were performed in the horizontal meridian for each eye by using the high-resolution scan protocol (scan length 10 mm; transverse axial resolution: 512 1,024 pixels). Scans were centered on the corneal vertex according to the strong anterior surface reflection. As done 45

3 TABLE 1 Demographic Characteristics Characteristic FLACS Group CPCS Group P a CDVA before surgery (logmar) 0.35 ± ± 0.16 NS Axial length (mm) NS Right eye vs left eye 13/20 20/13 NS First eye on surgery NS FLACS = femtosecond laser-assisted cataract surgery; CPCS = conventional phacoemulsification cataract surgery; CDVA = corrected distance visual acuity; NS = not significant a P <.05 was considered significant. TABLE 2 Characteristics of Capsulotomies and ELP a Time After Sugery FLACS Group CPCS Group P b Diameter of rhexis (mm) b 7 days 5.62 ± ± months 5.64 ± ± year 5.65 ± ± Deviation area (mm 2 ) 7 days 1.04 ± ± months 1.26 ± ± year 1.29 ± ± Relative error (%) 7 days 4.36 ± ± months 5.29 ± ± year 5.44 ± ± Difference in ELP (mm) 6 months 0.32 ± ± year 0.43 ± ± 0.29 >.05 ELP = effective lens position; FLACS = femtosecond laser-assisted cataract surgery; CPCS = conventional phacoemulsification cataract surgery a The diameter of the surgical rhexis (mm), the deviation area (mm 2 ) compared to the area of the theoretical rhexis, and the difference between ELP observed versus theoretical calculated are reported in millimeters. b Intra-individual. for Pentacam measurements, a caliper was made from the anterior corneal vertex to the lens plane, which appeared as a hyperreflective signal. The distance from the anterior corneal surface to the lens plane was defined as the postoperative lens position (Figure B, available in the online version of this article). A wavefront analysis was used to measure higher order aberrations. To evaluate shift and tilt of the lens, particular attention was paid to measure third order aberrations such as vertical and horizontal coma (Z 3-1 and Z 3 1 ).14 Statistical Analysis Statistical analysis was performed using Statview software (Optima, Floirac, France) and Excel software (Microsoft Corporation, Redmond, WA). For comparison of baseline demographics and clinical characteristics between groups, categorical data were analyzed using the Fisher s exact test and continuous data using paired t tests. Repeated measures analyses of variance were used to analyze the evolution of shape of the anterior capsulotomy over time. Differences were considered significant when the P value was less than.05. RESULTS Sixty-six eyes of 33 consecutive patients were included in the analysis (Table 1). Among the 33 FLACS procedures, we observed 77% complete capsulotomies. Eight tags were noted (24.4%). No posterior capsular tears, ruptures, or nucleus drops were reported. 46 Copyright SLACK Incorporated

4 Figure 1. Uncorrected distance visual acuity (UDVA) and corrected distance visual acuity (CDVA) at 1 year postoperatively in the femtosecond laser-assisted cataract surgery group (FLACS). There was a significant difference between the FLACS and CPCS groups at all examinations (Table 2). Femtosecond laser anterior capsulotomies were smaller and closer to the target than manual anterior capsulotomies. Taking a perfect circle as reference, a significantly larger deviation surface was observed in the CPCS group at 7 days, 6 months, and 1 year (Table 2). The relative error was significantly higher in the CPCS group compared to the FLACS group at each evaluation (Table 2). The size of the manual continuous curvilinear capsulorhexis changed over time (P =.017), whereas there was no significant evolution of the size or shape of the anterior capsulotomy in the FLACS group over time (P >.05). The ELP difference (ELP theoretical minus calculated) was less in the FLACS group compared to the CPCS group. Differences between the two groups did not reach statistical significance (Table 2). The corrected distance visual acuity (logmar) in the FLACS group was not statistically significant when compared with the CPCS group. This comparison includes intra-individual or inter-individual variability (Figures 1-2). Estimation of optical aberrations by coma was 0.24 ± 0.12 µm at 6 months and 0.26 ± 0.13 µm at 1 year in the FLACS group. The values were not statistically significant when compared with the CPCS group (P >.05) (Figure 3). Journal of Refractive Surgery Vol. 33, No. 1, 2017 Figure 2. Uncorrected distance visual acuity (UDVA) and corrected distance visual acuity (CDVA) at 1 year postoperatively in the conventional phacoemulsification cataract surgery group (CPCS). Figure 3. Spherical equivalent of the refractive error in diopters (D) at 1 year postoperatively. FLACS = femtosecond laser-assisted cataract surgery; CPCS = conventional phacoemulsification cataract surgery DISCUSSION To the best of our knowledge, this study is remarkable for having compared the changes over 1 year of capsulorhexis in FLACS versus CPCS using an intra-individual comparison. This analysis decreases to their minimum the difference between both groups in terms of population characteristics and provides similar groups. We found that more precise capsulotomy sizing can be achieved with femtosecond laser than with manual continuous curvilinear capsulorhexis. This result confirms several studies that demonstrated a statistical advantage for FLACS in terms of precision, accuracy, and reproducibility in human eyes. 8,15-17 We also found that anterior capsulotomies in the CPCS group were systematically larger than the intended target. Rhexis shapes were also modified over time. Their size had a tendency to decrease and to be closer to the targeted rhexis. Their decreases were explained by a capsular retraction secondary to the capsular bag fibrosis. We observed no significant modification of the anterior capsular diameter in the FLACS group, but a trend toward an expansion. A higher number of patients would allow us to reach statistical significance results. However, those results tend to report that femtosecond laser capsulotomies lead to less capsular bag fibrosis or a slower progression. Greater regularity on capsulotomy edges with the femtosecond laser could be an explanation for this observation. 1 FLACS provides more resistant capsulotomy edges, as suggested by Auffarth et al. 18 in a laboratory study of pig eyes. However, modifications of the shape of the capsulorhexis with the femtosecond laser could be important, as shown in Figure 4. Residual anterior 47

5 Figure 4. Change over time of the capsulorhexis in a multifocal intraocular lens case with femtosecond laser anterior capsulotomy. (A) Capsulorhexis on day 7 after surgery showing a perfect circular rhexis. (B) The same capsulorhexis 6 months after surgery. The red circle indicates minor modification, a notch, within the anterior capsulotomy. (C) The same capsulorhexis 1 year after surgery. The same notch can be observed (red circle). cortex was observed in the photograph at 7 days. The location of the significant modification in the shape of the capsulorhexis corresponds to the location of the residual anterior cortex. Moisturized residual anterior cortex could cause a contraction of the rhexis, which is responsible for loss of regularity. This modification of the anterior capsulotomy performed with FLACS could lead to a better stability of the IOL and hence to a decrease in lens tilt and better stability of refractive outcome over time. 16 Coma-like aberrations in both groups were comparable at 6 months and 1 year. The occurrence of comalike aberrations after cataract surgery is mainly related to the existence of a tilt of the IOL 14,19 or to a residual astigmatism. We did not perform limbal relaxing incisions in the FLACS group, which might have influenced results. We did not formally measure IOL title in this study, but results of the coma-like aberration confirm the great stability of the lens with both techniques. A single study observed a significant decrease of optical aberration in the FLACS group compared to the CPCS group. 20 The absence of difference in refractive error agrees with the absence of modification in ELP between groups. We also observed excellent results for the corrected distance visual acuity in both groups over 1 year after surgery, confirming that CPCS and FLACS are two reliable techniques, as noted by Abell et al. 21 These results agree with Roberts et al. 7 and Szigeti et al., 22 who did not find significant differences in corrected distance visual acuity and refractive error between the two techniques. The absence of significant differences in our study in terms of ELP, refractive error, coma, and corrected distance visual acuity should be taken with caution given the small number of patients included in this study. We did not perform arcuate incisions to manage astigmatism in either group. As for arcuate incisions, the same assumption could be made for lens softening, which was not evaluated in this study. In addition, CPCS is a reliable and standardized procedure, whereas FLACS is still in progress. Software and the surgeon s experience improve over time and will add accuracy and reliability to the procedure. Our relatively high rate of tags on anterior capsulotomy could also be explained by technical development, as shown by Roberts et al. 23 Indeed, refractive results and safety in FLACS will progress with surgeon experience. 23 More precise capsulotomy sizing can be achieved with femtosecond laser compared to the manual continuous curvilinear capsulorhexis. Femtosecond laser capsulotomies were less modified over time but did not provide benefits on ELP and visual quality. FLACS represents a possible technological breakthrough in cataract surgery, but improvements in the procedure have to be made to enhance patient satisfaction with this new technique. AUTHOR CONTRIBUTIONS Study concept and design (JCR-S, AB, DM); data collection (CP, FC); analysis and interpretation of data (CP, FC, CM, MG); writing the manuscript (CP, FC); critical revision of the manuscript (JCR-S, AB, CM, MG, DM); statistical expertise (CM); supervision (JCR-S, AB, MG, DM) REFERENCES 1. Day AC, Gartry DS, Maurino V, Allan BD, Stevens JD. Efficacy of anterior capsulotomy creation in femtosecond laser-assisted cataract surgery. J Cataract Refract Surg. 2014;40: Dooley IJ, O Brien PD. Subjective difficulty of each stage of phacoemulsification cataract surgery performed by basic surgical trainees. J Cataract Refract Surg. 2006;32: Neuhann T. Theory and surgical technic of capsulorhexis [article in German]. Klin Monbl Augenheilkd. 1987;190: Gimbel HV, Neuhann T. Development, advantages, and methods of the continuous circular capsulorhexis technique. J Cataract Refract Surg. 1990;16: Gimbel HV, Neuhann T. Continuous curvilinear capsulorhexis. J Cataract Refract Surg. 1991;17: Cekiç O, Batman C. The relationship between capsulorhexis size and anterior chamber depth relation. Ophthalmic Surg Lasers. 1999;30: Erratum in: Ophthalmic Surg Lasers. 1999;30: Roberts TV, Lawless M, Chan CC, et al. Femtosecond laser cataract surgery: technology and clinical practice. Clin Experiment Ophthalmol. 2013;41: Copyright SLACK Incorporated

6 8. Friedman NJ, Palanker DV, Schuele G, et al. Femtosecond laser capsulotomy. J Cataract Refract Surg. 2011;37: Erratum in: J Cataract Refract Surg. 2011;37: Haigis W. IOL power calculations. Ophthalmology. 2010;117: Dooley I, Charalampidou S, Nolan J, Loughman J, Molloy L, Beatty S. Estimation of effective lens position using a method independent of preoperative keratometry readings. J Cataract Refract Surg. 2011;37: Barkana Y, Gerber Y, Elbaz U, et al. Central corneal thickness measurement with the Pentacam Scheimpflug system, optical low-coherence reflectometry pachymeter, and ultrasound pachymetry. J Cataract Refract Surg. 2005;31: Ho J-D, Liou S-W, Tsai RJ-F, Tsai C-Y. Estimation of the effective lens position using a rotating Scheimpflug camera. J Cataract Refract Surg. 2008;34: Lackner B, Schmidinger G, Skorpik C. Validity and repeatability of anterior chamber depth measurements with Pentacam and Orbscan. Optom Vis Sci. 2005;82: Atchison DA. Design of aspheric intraocular lenses. Ophthalmic Physiol Opt. 1991;11: Palanker DV, Blumenkranz MS, Andersen D, et al. Femtosecond laser-assisted cataract surgery with integrated optical coherence tomography. Sci Transl Med. 2010;2: Kránitz K, Takacs A, Miháltz K, Kovács I, Knorz MC, Nagy ZZ. Femtosecond laser capsulotomy and manual continuous curvilinear capsulorrhexis parameters and their effects on intraocular lens centration. J Refract Surg. 2011;27: Dick HB, Conrad-Hengerer I, Schultz T. Intraindividual capsular bag shrinkage comparing standard and laser-assisted cataract surgery. J Refract Surg. 2014;30: Auffarth GU, Reddy KP, Ritter R, Holzer MP, Rabsilber TM. Comparison of the maximum applicable stretch force after femtosecond laser-assisted and manual anterior capsulotomy. J Cataract Refract Surg. 2013;39: Taketani F, Matuura T, Yukawa E, Hara Y. Influence of intraocular lens tilt and decentration on wavefront aberrations. J Cataract Refract Surg. 2004;30: Miháltz K, Knorz MC, Alió JL, et al. Internal aberrations and optical quality after femtosecond laser anterior capsulotomy in cataract surgery. J Refract Surg. 2011;27: Abell RG, Darian-Smith E, Kan JB, Allen PL, Ewe SYP, Vote BJ. Femtosecond laser-assisted cataract surgery versus standard phacoemulsification cataract surgery: outcomes and safety in more than 4000 cases at a single center. J Cataract Refract Surg. 2015;41: Szigeti A, Kránitz K, Takacs AI, Miháltz K, Knorz MC, Nagy ZZ. Comparison of long-term visual outcome and IOL position with a single-optic accommodating IOL After 5.5- or 6.0-mm femtosecond laser capsulotomy. J Refract Surg. 2012;28: 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: Journal of Refractive Surgery Vol. 33, No. 1,

7 Figure A. Determination of the deviation area with drawing software on slit-lamp capsulotomy pictures of a femtosecond laser capsulotomy at 7 days after surgery. The deviation areas outside and inside the optimal rhexis are in green and blue, respectively. Figure B. Visante optical coherence tomography (Carl Zeiss Meditec, Jena, Germany) scan. Effective lens position 1 year after surgery. The scan was centered on the corneal vertex as determined by its anterior surface reflection. A caliper measured the anterior corneal vertex to the lens plane, which appeared with hyperreflective signal. The distance from the anterior corneal surface to the lens was defined as the postoperative lens position.