Gábor László Sándor

Intraocular lens tilt and decentration measured by scheimpflug camera following manual or femtosecond laser-created continuous circular capsulotomy

PURPOSE To compare intraocular lens (IOL) decentration and tilt following a circular capsulotomy created with a femtosecond laser (laser CCC) to a manually performed continuous curvilinear capsulorrhexis (manual CCC). METHODS In a prospective, randomized study, a laser CCC (Alcon LenSx Inc) was performed in 20 eyes from 20 patients and a manual CCC was performed in 25 eyes from 25 patients. Intraocular lens decentration and tilt were measured using a Scheimpflug camera (Pentacam, Oculus Optikgeräte GmbH) 1 year after surgery. Uncorrected (UDVA) and corrected distance visual acuity (CDVA) and manifest refraction were also determined postoperatively. Between-group differences of IOL decentration and tilt as well as the correlation between IOL decentration and postoperative refractive changes and between IOL tilt and visual acuity were analyzed. RESULTS Horizontal and vertical tilt were significantly higher in the manual CCC group (P=.007 and P<.001, respectively). Lenses implanted after manual CCC showed greater horizontal and total decentration (P=.034 and P=.022, respectively). Significant differences were found in the homogeneity of dichotomized IOL vertical tilt and both horizontal and total decentration distribution (P=.008, P=.036, and P=.017, respectively). Total IOL decentration showed a significant correlation with changes in manifest refraction values between 1 month and 1 year after surgery (R=0.33, P=.032). A significant correlation was noted between IOL vertical tilt and CDVA (R(2)=0.17, β=-0.41, 95% confidence limit: -0.69 to -0.13, P=.005). CONCLUSIONS Continuous curvilinear capsulorrhexis created with a femtosecond laser resulted in a more stable refractive result and less IOL tilt and decentration than manual CCC.

Complications of femtosecond laser-assisted cataract surgery.

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. Juhász, and Slade are consultants to Alcon‐Lensx, Inc. No other author has a financial or proprietary interest in any material or method mentioned.

Comparison of the mechanical properties of the anterior lens capsule following manual capsulorhexis and femtosecond laser capsulotomy.

PURPOSE To evaluate and compare the mechanical properties of anterior capsule openings performed with the continuous curvilinear capsulorhexis (CCC) technique and femtosecond laser capsulotomy (FLC) in ex vivo porcine lens capsule specimens. METHODS Fresh porcine eyes were included in the study (CCC group, n = 50; FLC group, n = 30). The capsule openings were stretched with universal testing equipment until they ruptured. The rupture force and circumference stretching ratio were evaluated. The morphologic profile of the cut capsule edges was evaluated using scanning electron microscopy (SEM). RESULTS The average rupture force was higher in the CCC group (median: 155 mN; interquartile range [IQR]: 129 to 201 mN; range: 71 to 294 mN) than in the FLC group (median: 119 mN; IQR: 108 to 128 mN; range: 91 to 142 mN) (P < .01, Mann-Whitney U test). The average circumference stretching ratio in the CCC group was greater (median: 150%; IQR: 146% to 156%; range: 136% to 161%) than in the FLC group (median: 148%; IQR: 145% to 150%; range: 141% to 154%) (P = .0468, Mann-Whitney U test). When less than 71 mN, no capsular tear occurred in either group. When less than 91 mN, no capsular tear occurred in the FLC group, whereas at 91 mN, the probability of capsular tears was 9% for the CCC group. SEM examination found that the CCC group had smooth edges, whereas those of the FLC group were gently serrated. CONCLUSIONS According to the current results in a porcine eye model, FLC had less average resistance to capsule tear than CCC, but the weakest openings were seen in the CCC group.

The Effect of Femtosecond Laser Capsulotomy on the Development of Posterior Capsule Opacification

PURPOSE To evaluate and compare the effects of femtosecond laser-assisted anterior capsulotomy and manual anterior capsulorhexis on posterior capsule opacification (PCO) development. METHODS Femtosecond laser-assisted anterior capsulotomy was performed in 40 eyes of 40 patients (FS group) and manual anterior capsulorhexis was performed in 39 eyes of 39 patients (CCC group). An AcrySof one-piece hydrophobic acrylic intraocular lens (Alcon Laboratories, Inc., Fort Worth, TX) was implanted in all eyes. The PCO level was measured using Open-Access Systematic Capsule Assessment (OSCA) software 18 to 26 months after surgery. Postoperative intraocular lens position (ie, tilt and decentration) was measured using Scheimpflug images (Pentacam; Oculus Optikgeräte GmbH, Wetzlar, Germany). RESULTS There was no statistically significant difference in age, axial length, and follow-up time between the two groups (P > .05). Vertical tilt, horizontal and total decentration of intraocular lenses, and PCO proved to be significantly higher in the CCC group (P = .03, .04, .03, and .01, respectively). After adjusting for axial length and follow-up time, manual anterior capsulorhexis was found to be a significant predictor of higher PCO scores in the multivariable regression model (β: 0.33; 95% CI: 0.01 to 0.65; P = .04). Vertical tilt affected PCO scores after adjusting for axial length and follow-up time (β: 0.07; 95% CI: 0.01 to 0.12; P = .02). No capsulotomies were performed during follow-up in either group. CONCLUSIONS Femtosecond laser-assisted anterior capsulotomy proved to be a safe procedure for postoperative PCO rates. Due to better intraocular lens position, femtosecond laser-assisted anterior capsulotomy resulted in slightly decreased PCO scores; however, evaluating its clinical significance requires further studies.

Corneal Changes in Progressive Keratoconus After Cross-linking Assessed by Scheimpflug Camera

PURPOSE To evaluate corneal changes after corneal cross-linking (CXL) in progressive keratoconus with Scheimpflug imaging. METHODS This prospective analysis included 40 eyes from 22 patients with progressive keratoconus. Corneal CXL was performed in 25 eyes (CXL group) and 15 fellow eyes served as controls (control group). Uncorrected (UDVA) and corrected distance visual acuity (CDVA), thinnest corneal thickness (ThCT), posterior elevation, and Holladay equivalent keratometry values (K1, K2) were determined with Pentacam (Oculus Optikgeräte GmbH) before and 1 year after CXL. Area under the receiver operator characteristic (ROC) curve and multivariable general estimating equation models were used to determine the most sensitive parameters of corneal changes. RESULTS Manifest sphere (-2.55±3.21 to -1.48±2.39 diopters [D], P=.02), UDVA (0.23±0.25 to 0.31±0.25, P<.001), and CDVA (0.58±0.28 to 0.72±0.19, P=.019) improved significantly in the CXL group. Significant decreases were found in ThCT (472.53±33.18 to 440.53±38.67 μm, P<.001), posterior elevation (68.33±28.69 to 22.67±16.21, P<.001), and keratometry values (K1 [45.06±4.55 to 43.51±4.67 D, P<.001], K2 [48.39±5.41 to 46.71±5.67 D, P<.001]) in the CXL group. These parameters remained stable in controls (P>.05). According to ROC analysis, posterior elevation change was the most characteristic parameter of corneal change after CXL (area under the curve=0.99). General estimating equation model showed that CXL (P=.001) and initial ThCT (P=.007) were significant predictors of decrease in posterior elevation with a significant negative interaction of initial ThCT on CXL effect (P=.005). CONCLUSIONS Posterior elevation is a sensitive parameter to monitor corneal remodeling after CXL. Corneal CXL showed augmented effect on corneal protrusion in eyes with thinner corneas.

Evaluation of Femtosecond Laser-Assisted and Manual Clear Corneal Incisions and Their Effect on Surgically Induced Astigmatism and Higher-Order Aberrations

PURPOSE To evaluate femtosecond laser-assisted and manual clear corneal incisions and their effect on surgically induced astigmatism (SIA) and corneal higher-order aberrations (HOAs). METHODS In a prospective randomized study, conventional phacoemulsification with a 2.8-mm clear corneal incision using a disposable keratome was performed in 20 eyes of 20 patients (manual group), and femtosecond laser-assisted cataract surgery with a 2.8-mm biplanar clear corneal tunnel created by a femtosecond laser (LenSx; Alcon Laboratories, Inc., Aliso Viejo, CA) was performed in 20 eyes of 20 patients (femtosecond laser group). Corneal topography readings and corneal wavefront aberrations (diameter: 9.0 mm) were obtained using a Scheimpflug camera (Pentacam HR; Oculus Optikgerate, Wetzlar, Germany) preoperatively and 3 months postoperatively. RESULTS There was no significant difference in SIA between the groups (femtosecond laser group: 0.47 ± 0.13 vs manual group: 0.41 ± 0.14; P = .218), but the axis deviation of the SIA axis from the previously planned axis was significantly smaller in the femtosecond laser group compared to the manual group (4.47°± 2.59° vs 7.38°± 4.72°, respectively; P = .048). Corneal HOAs increased significantly in both groups (femtosecond laser group: 0.13 ± 0.09 to 0.18 ± 0.12, P = .025; manual group: 0.13 ± 0.05 to 0.15 ± 0.05, P = .002), but preoperative and postoperative values did not differ significantly between them (P = .472 and .078, respectively). Lower-order and total corneal aberration values remained stable in both groups (P > .05). CONCLUSIONS There was no difference in SIA and induced HOAs between manual and femtosecond laser-created clear corneal incisions.

Laser refractive cataract surgery with a femtosecond laser after penetrating keratoplasty: case report.

Laser Refractive Cataract Surgery With a Femtosecond Laser After Penetrating Keratoplasty: Case Report Cataract surgery after corneal transplant must minimize endothelial cell damage because postoperative transplant cell counts are lower than those of normal corneas. As the femtosecond laser was successfully introduced in cataract surgery,1,2 we applied this technology in an eye that had a previous penetrating corneal transplant. A 33-year-old man had a 7.0-mm diameter penetrating keratoplasty in his right eye 6 years prior to presentation. He later developed posterior polar cataract. The cornea was clear and corrected distance visual acuity (CDVA) was 20/40. Femtosecond laser–assisted cataract surgery (Alcon LenSx, Aliso Viejo, California) was performed as described previously.1,2 The corneal scar was peripheral to the planned capsulotomy. Centration was assessed using the pupillary edge. A 4.8-mm capsulorrhexis was performed with the femtosecond laser and the nucleus was liquefi ed. Corneal wounds were created with a 2.8-mm and 15° blade so as not to interfere with the transplant scar. The anterior chamber was fi lled with viscoelastic material, and the edge of the capsulorrhexis was identifi ed with a cystotome and removed with a capsulorrhexis forceps. After hydrodissection, the lens nucleus and cortex were aspirated with the irrigation-aspiration handpiece. A 12.00-diopter (D) hydrophobic acrylic posterior chamber intraocular lens (Acrysof; Alcon Laboratories Inc, Ft Worth, Texas) was implanted in the capsular bag. On postoperative day 1, CDVA was 20/200 because of slight corneal edema, which improved to 20/25 over the next 3 months. Subjective refraction was stable at 1.25 D sphere and 6.00 D cylinder at 1-year followup, with CDVA of 20/20. Corneal thickness measured with a Scheimpfl ug camera (Pentacam HR; Oculus Optikgeräte GmbH, Wetzlar, Germany) was 609 μm preoperatively and 598 μm 1 month postoperatively. We report the fi rst patient having successful laser refractive cataract surgery after penetrating keratoplasty. The curved interface aligned perfectly along the transplanted and donor cornea. Optical coherence tomography identifi ed the scar line of the transplant and the scar did not interfere with the laser capsulotomy. The corneal incisions were created manually because of the peripheral localization of the transplant scar. As reported previously,1 the use of a femtosecond laser may minimize the ultrasound energy required to remove the nucleus, thereby preserving endothelial cells in postoperative transplant corneas. Graft failure following phacoemulsifi cation and intraocular lens implantation is reported to be between 3% and 8%.3,4 Endothelial cell loss related to ultrasound use is usually markedly higher in transplanted corneas than in normal, unoperated eyes.5 In our case, most likely due to the use of the femtosecond laser to liquefy the nucleus, no ultrasound was required to remove the lens and endothelial cell count did not change up to 1 year after surgery. Zoltán Z. Nagy, MD, DSC Ágnes I. Takács, MD Tamás Filkorn, MD Éva Juhász, MD Gábor Sándor, MD Andrea Szigeti, MD Budapest, Hungary Michael C. Knorz, MD Mannheim, Germany

Evaluation of the Mechanical Properties of the Anterior Lens Capsule Following Femtosecond Laser Capsulotomy at Different Pulse Energy Settings

PURPOSE To evaluate and compare the mechanical properties of anterior capsule opening performed with femtosecond laser capsulotomy at different energy settings in ex vivo porcine anterior lens capsule specimens. METHODS Twenty-five fresh porcine eyes per group were included in the study. Femtosecond laser capsulotomy was performed with three different pulse energy levels: 2 µJ (low energy group), 5 µJ (intermediate energy group), and 10 µJ (high energy group). The capsule openings were stretched with universal testing equipment until they ruptured. The morphologic profile of the cut capsule edges was evaluated using scanning electron microscopy. RESULTS The high energy group had significantly lower rupture force (108 ± 14 mN) compared to the intermediate energy group (118 ± 10 mN) (P < .05) and low energy group (119 ± 11 mN) (P < .05), but the difference between the intermediate energy and low energy groups was not significant (P = .9479). The high energy group had significantly lower circumference stretching ratio (144% ± 3%) compared to the intermediate energy group (148% ± 3%) (P < .05) and low energy group (148% ± 3%) (P < .05), but the difference between the intermediate energy group and low energy group was not significant (P = .9985). Scanning electron microscopy images showed that the edge was only serrated with low and intermediate energy, but additional signs of collagen melting and denaturation were observed at high energy. CONCLUSIONS Anterior capsule openings created at a high energy level were slightly weaker and less extensible than those created at low or intermediate levels, possibly due to the increased thermal effect of photo-disruption.

One-Day Use of Preoperative Topical Nonsteroidal Anti-Inflammatory Drug Prevents Intraoperative Prostaglandin Level Elevation During Femtosecond Laser-Assisted Cataract Surgery

ABSTRACT Purpose: To determine if pretreatment with topical nonsteroidal anti-inflammatory drug (NSAID) prior to femtosecond laser-assisted cataract surgery (FLACS) prevents intraoperative prostaglandin level elevation as a potential risk factor of postoperative complications. Patients and methods: Thirty-six patients with clinically significant cataract and without any concomitant general or ophthalmic disease were enrolled into the three age-matched groups of the study. The mean age of the patients was 62.3 ± 13.1 years. The first group of patients underwent traditional phacoemulsification (Control group), on the second group of patients FLACS was performed, and the third group of patients received topical 0.1% nepafenac pretreatment for 1one day prior to FLACS. Before the phacoemulsification part of the cataract surgery, approximately 110 µL of aqueous humor was collected in all groups. Total prostaglandin concentrations of the collected aqueous humor samples were evaluated by enzyme immunoassay (EIA). Results: The mean of the total prostaglandin concentrations of the aqueous humor samples was 208.8 ± 140.5 pg/mL in patients in the control group, 1449.1 ± 1019.7 pg/mL in the FLACS group (p > 0.001), and 92.2 ± 51.7 pg/mL in the group pretreated with topical NSAID before the FLACS (p > 0.001 compared to FLACS; p > 0.01 compared to control), respectively. Conclusions: FLACS surgery increases intracameral prostaglandin concentration. However, using preoperative 1-day-long nonsteroid anti-inflammatory drops prior to FLACS, this intraoperative increase diminishes. Our study raises the possibility that NSAID pretreatment may be routinely administered before FLACS cataract surgeries to achieve a further decrease in the potential complications of increased total prostaglandin concentration during FLACS surgeries.

Changes of Corneal Topography Indices After CXL in Progressive Keratoconus Assessed by Scheimpflug Camera

PURPOSE To evaluate the accuracy of Scheimpflug camera topography indices in detecting the therapeutic effect of corneal collagen cross-linking (CXL) on progressive keratoconus in the long term. METHODS Fifty eyes of 25 patients with keratoconus were enrolled. CXL was performed in 25 eyes with progressive keratoconus (CXL group) and 25 fellow eyes with nonprogressive keratoconus served as controls. Thinnest corneal thickness, anterior keratometry (flat, steep), and keratoconus indices were measured with Scheimpflug camera before and 12 to 25 months after CXL. Regression analysis was used to evaluate the influence of corneal thickness and follow-up time on flattening effect of CXL. RESULTS At baseline, steep keratometric values were significantly higher and thinnest corneal thickness values were lower in the CXL group (P = .027, .034), parallel with increased values of keratoconus indices: index of surface variance (P = .013), index of vertical asymmetry (P = .038), keratoconus index (P = .019), center keratoconus index (P = .039), index of height asymmetry (P = .037), index of height decentration (P = .0016), and radius minimum (P = .008). After adjustment for thinnest corneal thickness and follow-up time, CXL showed significant flattening effect expressed by changes in radius minimum (P < .001), index of surface variance (P = .03), keratoconus index (P = .006), center keratoconus index (P = .03), and index of height asymmetry (P = .026). Thinnest corneal thickness had significant influence on changes of index of surface variance (P = .049), index of vertical asymmetry (P = .01), and center keratoconus index (P = .03). Follow-up time showed no significant influence in any models (P > .05). CONCLUSIONS Topographic indices indicate corneal flattening after CXL in the long term. Monitoring keratoconus index and index of height asymmetry should be the preferred choice in daily clinical practice because changes in values of these indices are independent from initial corneal thickness.