Tamás Filkorn

Initial clinical evaluation of an intraocular femtosecond laser in cataract surgery.

PURPOSE To evaluate femtosecond laser lens fragmentation and anterior capsulotomy in cataract surgery. METHODS Anterior capsulotomy and phacofragmentation procedures performed with an intraocular femtosecond laser (LenSx Lasers Inc) were initially evaluated in ex vivo porcine eyes. These procedures were then performed in an initial series of nine patients undergoing cataract surgery. In addition to standard intraoperative assessments (including capsulotomy diameter accuracy and reproducibility), optical coherence tomography was used to evaluate human procedures. RESULTS For an intended 5-mm capsulorrhexis in porcine eyes, average achieved diameters were 5.88+/-0.73 mm using a standard manual technique and 5.02+/-0.04 mm using the femtosecond laser. Scanning electron microscopy revealed equally smooth cut edges of the capsulotomy with the femtosecond laser and manual technique. Compared to control porcine eyes, femtosecond laser phacofragmentation resulted in a 43% reduction in phacoemulsification power and a 51% decrease in phacoemulsification time. In a small series of human clinical procedures, femtosecond laser capsulotomies and phacofragmentation demonstrated similarly high levels of accuracy and effectiveness, with no operative complications. CONCLUSIONS Initial results with an intraocular femtosecond laser demonstrate higher precision of capsulorrhexis and reduced phacoemulsification power in porcine and human eyes.

Central corneal volume and endothelial cell count following femtosecond laser-assisted refractive cataract surgery compared to conventional phacoemulsification

PURPOSE To compare the effect of conventional phacoemulsification and femtosecond laser-assisted cataract surgery on the cornea using Scheimpflug imaging and noncontact specular microscopy. METHODS In each group, 38 eyes (38 patients) underwent cataract surgery using either femtosecond laser-assisted (Alcon LenSx laser) (femtolaser group) or conventional phacoemulsification (phaco group). Central corneal thickness, 3-mm corneal volume, and Pentacam Nucleus Staging (PNS) were determined by a rotating Scheimpflug camera (Pentacam HR, Oculus Optikgeräte GmbH), and the volume stress index was calculated at 1 day and 1 month postoperatively. Endothelial cell count was measured by noncontact specular microscopy preoperatively, 1 day, 1 week, and 1 month postoperatively. RESULTS Central corneal thickness was significantly higher in the phaco group (607±91 μm) than in the femtolaser group (580±42 μm) on day 1, but did not differ significantly preoperatively and at 1 week and 1 month. Volume stress index at day 1 was significantly lower in the femtolaser group than in the phaco group (P<.05) but did not differ significantly at 1 month. Multivariate regression analysis showed that the type of surgery had a significant effect on central corneal thickness. CONCLUSIONS Femtosecond laser-assisted cataract surgery causes less corneal swelling in the early postoperative period and may cause less trauma to corneal endothelial cells than manual phacoemulsification.

Comparison of IOL power calculation and refractive outcome after laser refractive cataract surgery with a femtosecond laser versus conventional phacoemulsification

PURPOSE To compare intraocular lens (IOL) power calculation and refractive outcome between patients who underwent laser refractive cataract surgery with a femtosecond laser and those with conventional cataract surgery. METHODS In this prospective study, 77 eyes from 77 patients underwent laser refractive cataract surgery (laser group; Alcon LenSx femtosecond laser), and conventional cataract surgery with phacoemulsification was performed in 57 eyes from 57 patients (conventional group). Biometry was done with optical low coherence reflectometry (Lenstar LS900, Haag-Streit AG), and IOL calculation was performed with third-generation IOL formulas (SRK/T, Hoffer Q, and Holladay). The refractive outcome was analyzed using the mean absolute error (MAE; difference between predicted and achieved postoperative spherical equivalent refraction), and multivariable regression analysis was performed to compare the two groups. RESULTS No significant differences were found between age, axial length, keratometry, and preoperative corrected visual acuity in the laser and conventional groups (P>.05; Mann-Whitney U test). At least 6 weeks after surgery, MAE was significantly lower in the laser group (0.38±0.28 diopters [D]) than in the conventional group (0.50±0.38 D) (P=.04). The difference was the greatest in short (axial length <22.0 mm, 0.43±0.41 vs 0.63±0.48) and long (axial length >26.0 mm, 0.33±0.24 vs 0.63±0.42) eyes. CONCLUSIONS Laser refractive cataract surgery with a femtosecond laser resulted in a significantly better predictability of IOL power calculation than conventional phacoemulsification surgery. This difference is possibly due to a more precise capsulorrhexis, resulting in a more stable IOL position.

Effect of Femtosecond Laser Cataract Surgery on the Macula

PURPOSE To compare the effect of conventional and femtosecond laser-assisted (Alcon LenSx Inc) phacoemulsification on the macula using optical coherence tomography (OCT). METHODS Twenty eyes of 20 patients underwent uneventful cataract surgery in both study groups: femtosecond laser-assisted (laser group) and conventional phacoemulsification (control group). Macular thickness and volume were evaluated by OCT preoperatively and 1 week and 1 month postoperatively. Primary outcomes were OCT retinal thickness in 3 macular areas and total macular volume at 1 week and 1 month postoperative. Secondary outcomes were changes in retinal thickness at 1 week and 1 month postoperatively, with respect to preoperative retinal thickness values and effective phacoemulsification time. RESULTS Multivariable modeling of the effect of surgery on postoperative macular thickness showed significantly lower macular thickness in the inner retinal ring in the laser group after adjusting for age and preoperative thickness across the time course (P=.002). In the control group, the inner macular ring was significantly thicker at 1 week (mean: 21.68 μm; 95% confidence limit [CL]: 11.93-31.44 μm, P<.001). After 1 month, this difference decreased to a mean of 17.56 μm (95% CL: -3.21-38.32 μm, P=.09) and became marginally significant. CONCLUSIONS Results of this study suggest that femtosecond laser-assisted cataract extraction does not differ in postoperative macular thickness as compared with standard ultrasound phacoemulsification.

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.

Anterior Segment OCT Imaging After Femtosecond Laser Cataract Surgery

PURPOSE To report the anterior segment imaging characteristics after femtosecond laser assisted cataract surgery. METHODS Cataract surgery was performed with the LenSx femtosecond laser (Alcon-LenSx Inc., Aliso Viejo, CA) in 40 eyes of 40 patients. The laser was programmed to perform a 4.5-mm capsulorhexis, a cross-pattern fragmentation of the nucleus, a 2.8-mm main incision, and a 1.0-mm side-port incision. The anterior segment was then analyzed using the Visante OCT anterior segment program (Zeiss-Meditec AG, Jena, Germany). RESULTS The preoperatively set treatment parameters correlated well with the achieved results. For the capsulorhexis, the femtosecond laser cut was programmed to start 350 μm behind the anterior lens capsule and OCT measured 377 ± 55.3 μm. Nucleus fragmentation was programmed to start 750 μm in front of the posterior capsule and end 550 μm behind the anterior capsule, and OCT measured 794 ± 111 and 568 ± 147 μm, respectively. The diameter of the capsulorhexis measured by OCT was 4.54 ± 0.2 mm, compared to the 4.5 mm programmed. CONCLUSIONS Anterior segment OCT imaging was able to detect the tissue changes within the lens after femtosecond laser capsulorhexis and nucleus fragmentation. The measured values correlated well with the planned treatment parameters.

Femtosecond laser cataract incision morphology and corneal higher-order aberration analysis.

PURPOSE Analysis of the femtosecond laser refractive lens surgery corneal incision configuration and corneal higher-order aberration (HOA) effect from the first postoperative day. METHODS High-resolution anterior segment optical coherence tomography was used to assess 20 eyes undergoing femtosecond laser refractive lens surgery with 2.2-mm minimal incision. The primary incision (tri-planar) actual length, cord length, surface angle, surface irregularity, and regional pachymetry values and the secondary incision (uni-planar) length, angle, surface irregularity, and pachymetry values were analyzed. Hartmann-Shack aberrometer was used to assess corneal HOAs to correlate the effect. Assessment was done preoperatively and 1 month postoperatively. RESULTS The actual length, cord length, and surface angle means for the primary incision in the first postoperative day and month were 1.50 ± 0.1 and 1.47 ± 0.2 mm (P = .5), 1.41 ± 0.1 and 1.42 ± 0.2 mm (P = .8), and 27° ± 4° and 23° ± 5° (P = .07), respectively. The length and surface angle for the secondary incision in the first postoperative day and month were 1.17 ± 0.01 and 1.04 ± 0.1 mm (P = .05) and 52° ± 3° and 42° ± 5° (P = .007). The regional pachymetry values for the primary and secondary incisions were significantly increased in the first postoperative day and then significantly decreased after 1 month. All irregularities occurred in the posterior surface (endothelium): 2 cases of posterior gap (first day) and 1 case of posterior retraction (first month). The HOAs had not significantly changed preoperatively and after 1 month. CONCLUSIONS The femtosecond laser refractive lens surgery incision is stable and does not significantly change the HOA.

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

Analysis of Planned and Postoperatively Measured Flap Thickness After LASIK Using the LenSx Multifunctional Femtosecond Laser System

PURPOSE To evaluate LASIK corneal flaps using a multifunctional femtosecond laser suitable for cataract and corneal surgery (LenSx; Alcon Laboratories, Inc., Aliso Viejo, CA) and to compare the planned and postoperatively measured flap thickness using an anterior segment optical coherence tomography device (AS-OCT). METHODS Twenty patients (38 eyes) diagnosed as having myopia and myopic astigmatism were enrolled. LASlK was performed using the LenSx femtosecond laser for intracorneal flaps and the Wavelight Allegretto 400 excimer laser (Alcon Laboratories, Inc.) for intra- stromal photoablation. Desired flap thickness and diameter were 140.0 + 0.0 pm and 8.5 + 0.0 mm, respectively, whereas mean ablation depth and diameter of the excimer laser treatment were 67.9 ± 24.18 pm and 6.5 ± 0.08 mm, respectively. Entered data of the LenSx femtosecond laser were used to determine desired flap thickness, whereas AS-OCT (RTVue; Optovue, Inc., Fremont, CA) was used to measure flap thickness postoperatively. The Wilcoxon signed-rank test, dependent paired t test, and Friedman test were used for comparison of dependent and repeated measures. RESULTS There was no statistically significant difference in the planned and postoperatively measured flap thickness (140.0 ± 0.0 vs 140.28 _ 8.0 pm; P = .4067). Interfaces of the flaps had even surfaces according to the images and calculations on the AS-OCT device (P = .058). CONCLUSIONS Application of this multifunctional femtosecond laser performing LASIK proved to be a safe and effective method regarding predictability of flap thickness.

Intraocular femtosecond laser use in traumatic cataract

Purpose To report the use of femtosecond laser cataract surgery in a traumatic case. Methods A 38-year-old man had a penetrating eye injury while working with wire. The corneal laceration was sutured first. In the postoperative period, cortical cataract appeared in the crystalline lens; therefore, in the second session, cataract surgery was performed using a femtosecond laser system (Alcon-LenSx Lasers Inc.). Results Corneal incisions, an intact 4.5 mm capsulorhexis, and nucleus liquefaction were performed with the femtosecond laser. Corrected distance visual acuity was 0.9 1 month after surgery. Conclusions Femtosecond laser is an effective method in traumatic cataract cases after penetrating eye injury. Corneal incisions, capsulorhexis, and nucleus liquefaction can be performed precisely and safety.