In vitro immunohistochemical and morphological observations of penetrating corneal incisions created by a femtosecond laser used for assisted intraocular lens surgery.

PURPOSE: To compare inflammatory cell response and morphological aspects of femtosecond laser-created corneal incisions. SETTING: Department of Ophthalmology, Goethe-University, Frankfurt am Main, Germany. DESIGN: Experimental study. METHODS: In 16 of 22 human corneoscleral buttons, clear corneal tunnel incisions were created using a femtosecond laser (Lensx) with 7 µJ laser pulse energy on the outer periphery and manually using a phaco knife on the respective opposite side (180 degrees). In 6 corneas, no treatment was performed (controls). Corneas were then kept in organ culture for 12 or 48 hours, and the inflammatory reaction was evaluated using standard immunofluorescence analyses for monocytes (CD11b) and for dendritic cells (HLA-DR). For morphological analyses and apoptosis, van Gieson staining and terminal deoxynucleotidyl transferase deoxy-UTP-nick end labeling was performed. RESULTS: There were no statistically significant differences in inflammatory cell response between femtosecond laser corneal incisions and manually performed incisions. Apoptosis was significantly more pronounced in the femtosecond incisions. The ratio of dendritic cells between femtosecond incisions and manual incisions was 1:2 (12 hours and 48 hours; P=.07), the ratio of monocytes was 1:2 (12 hours and 48 hours; P=.08), and the ratio of apoptotic cells was 1:5 (12 hours) and 1:6 (48 hours) (P=.02). Femtosecond laser incisions showed a more sawtooth-like cutting edge than manual incisions. CONCLUSIONS: Femtosecond laser-created corneal incisions in human corneas showed no differences in inflammatory cell response but a significantly higher cell death rate than manually performed incisions, indicating an upregulated postoperative wound-healing response. FINANCIAL DISCLOSURE(S): Proprietary or commercial disclosures are listed after the references.

Morphological changes in the edge structures following femtosecond laser capsulotomy with varied patient interfaces and different energy settings.

BACKGROUND: To ascertain the morphological changes in the edge structure of femtosecond laser-derived capsulotomy specimens using varying patient interfaces and different laser pulse energies. METHODS: In this experimental clinical study femtosecond laser-assisted capsulotomies were performed in 30 eyes using the LenSx femtosecond laser (LenSx, Alcon, Fort Worth, TX, USA). Surgery was performed using either a rigid curved contact interface (group 1, 15 eyes) or a curved interface with a soft contact lens between cornea and interface (group 2, 15 eyes). The laser pulse-energy was set to 15 µJ in group 1 and to 5 µJ in group 2. After the removal of the anterior capsule, half of the specimens from each group underwent either further staining for light microscopy (LM) or scanning electron microscopy (SEM). Cell configuration, capsule shape, and edge abnormalities were analysed on a morphological basis. RESULTS: LM showed continuous anterior capsular incisions with a prominent demarcation line along the cutting edge, as well as tags and bridges, which were more pronounced in group 1. SEM revealed further smaller microgrooves and sawtooth patterns in both groups, and a more regular demarcation line configuration in group 2. CONCLUSION: A soft contact lens interface with a subsequent laser pulse energy of 5 µJ resulted in fewer tags and bridges, smoother edges, and a more regular and thinner demarcation line on specimens edges of femtosecond laser-performed capsulotomies compared to a rigid curved 15 µJ interface application.

Cell death and ultrastructural morphology of femtosecond laser-assisted anterior capsulotomy.

PURPOSE: To evaluate cell death and ultrastructural effects on capsulotomy specimens derived from femtosecond laser-assisted cataract surgery. METHODS: In 26 eyes, an anterior capsulotomy was performed using a femtosecond laser. In 10 eyes (group 1), the laser-pulse energy was set to 15 µJ using a rigid curved interface and in another 10 eyes (group 2) to 5 µJ using a curved interface combined with a soft contact lens. The control group (6 eyes, group 3) underwent manual anterior capsulorhexis using forceps. All extracted capsule specimens underwent cell death analysis using the TUNEL kit, ultrastructural analyses using atomic force microscopy (AFM), and scanning electron microscopy (SEM). Counterstaining was performed with 4',6-diamidino-2-phenylindol (DAPI) and hematoxylin-eosin (HE). RESULTS: Cell death was found in all capsule specimens along the cutting edge but was significantly more pronounced in group 1. DAPI and HE staining showed regular epithelial cell distribution with a demarcation line along the cutting edge of both laser groups, which was more pronounced in group 1. In AFM analysis, laser spot size in the femtosecond laser groups were in accordance with the preoperative planned size (P < 0.01). Cutting edges in SEM observations were smoother and more roundly shaped using 5 µJ (group 2). CONCLUSIONS: Cutting edges of femtosecond laser-performed capsulotomies are precise and laser spot lesions are within planned size. Cell death reaction depends on the laser pulse energy settings and can be reduced to the level observed in a manual capsulorhexis.

Influence of additional astigmatism on distance-corrected near visual acuity and reading performance.

AIM: To investigate the effect of astigmatism on near vision performance. METHODS: In a consecutive case series 23 eyes of 23 participants were fogged with 0 D, -0.75 D and -1.5 D of with-the-rule (WTR) and against-the-rule (ATR) astigmatism (cylindrical lenses without spherical compensation). All subjects were cyclopleged and distance corrected. Reading acuity (RAc) and speed (RS) were measured with standardised sentences, near visual acuity (NVA) was assessed using single optotypes (Snellen E), all presented on a thin film transistor display using the Salzburg Reading Desk (SRD). Data were analysed using Wilcoxon-matched-pairs test, regression analysis and Bland-Altman analysis. RESULTS: An increasing amount of astigmatism resulted in a decreased NVA (p=0.16 for -0.75 D, p=0.005 for -1.5 D) and RAc (p=0.002 for -0.75 D, p=0.014 for -1.5 D). WTR astigmatism caused a reduced NVA, RAc and lower RS compared with ATR astigmatism (p<0.001). NVA was better than RAc with no astigmatism, -0.75 D WTR and -1.5 D WTR (p=0.03 for 0 D, p<0.001 for -0.75 D, p=0.03 for -1.5 D). There was no difference between NVA and RAc for -0.75 D ATR and -1.5 D ATR (p=0.06 for -0.75 D, p=0.5 for -1.5 D). CONCLUSIONS: WTR astigmatism results in reduced reading parameters and NVA for -0.75 D and -1.5 D astigmatism compared with corresponding ATR astigmatism and no astigmatism added. No beneficial effect of astigmatism was detected.

Impact of crystalline lens opacification on effective phacoemulsification time in femtosecond laser-assisted cataract surgery.

PURPOSE: To compare effective phacoemulsification time in cataract surgery performed by manual phacoemulsification vs femtosecond laser-assisted lens fragmentation. DESIGN: Retrospective, consecutive, nonrandomized, comparative case series. METHODS: The setting was the Department of Ophthalmology, Goethe-University, Frankfurt, Germany. The study population included 150 eyes of 86 patients with senile cataract. In the intervention, 88 eyes (group 1) underwent femtosecond laser-assisted surgery (corneal incisions, capsulotomy, lens fragmentation) using the LenSx platform (Alcon) and residual lens work-up with pulsed ultrasound energy (Infiniti Vision System; Alcon). In 62 eyes (group 2), complete cataract removal was performed with phacoemulsification only, using pulsed ultrasound energy with the same device (Infiniti). Nucleus staging (Pentacam nucleus staging; PNS) was evaluated using Pentacam HR (Oculus); endothelial cell density was measured using specular microscopy (NonCon Robo). The main outcome measures were as follows. Mean preoperative PNS staging was assessed using an automatic ordinal scaling (PNS-O, grades 0-5) and a manually defined density grid derived from Scheimpflug imaging (PNS-P [%]). Effective phacoemulsification time and endothelial cell loss were evaluated in both groups. RESULTS: Preoperative PNS-O and PNS-P showed no significant difference between groups (P = 0.267). Overall mean effective phacoemulsification time was significantly lower in group 1 (1.58 ± 1.02 seconds) compared to 4.17 ± 2.06 seconds in group 2 (P = 0.001). Effective phacoemulsification time was significantly lower in group 1 for all PNS-O stages (P < 0.001). With increasing preoperative PNS-P, effective phacoemulsification time increased in both groups; however, this gain was noticeably, but not significantly, lower in group 2. Endothelial cell loss was significantly lower in group 1 (P = 0.02). CONCLUSIONS: Femtosecond laser-assisted cataract surgery allows a significant reduction in effective phacoemulsification time, which correlates positively with the preoperative lens opacity.

Light microscopy and scanning electron microscopy analysis of rigid curved interface femtosecond laser-assisted and manual anterior capsulotomy.

PURPOSE: To study the microanatomic edge structures of anterior lens capsule specimens derived from manual and femtosecond laser-assisted capsulotomies. SETTING: Department of Ophthalmology, Goethe-University, Frankfurt, Germany. DESIGN: Experimental study. METHODS: Of 60 eyes with lens removal and intraocular lens implantation, 30 received a manual capsulotomy and 30 received a femtosecond laser-assisted capsulotomy (Lensx, rigid curved interface, pulse energy 15 µJ, spot separation 4 µm, layer separation 3 µm). After anterior capsule removal, tissues were immediately fixed in 4.5% formalin. Approximately 30 minutes after fixation, the tissues were removed from the fixation containers and air dried for at least 2 hours. Fifteen capsules in each group had further staining for light microscopy (LM). The surface of the capsulotomy edge was the primary focus of LM and scanning electron microscopy (SEM). Cell configuration, capsule shape, and abnormalities were evaluated. RESULTS: Subjective LM and SEM analysis showed smooth edges at all magnifications, no cell destruction, and cells up to the cutting edge in the manual capsulotomy group. Light microscopy demonstrated almost continuous anterior capsule incisions of the femtosecond laser-assisted capsulotomy, a prominent demarcation line along the cutting edge, and several tags and bridges. Scanning electron microscopy showed microgrooves and valley- and mountain-like structures as signs of the photodisruption process. CONCLUSION: Compared with manual procedures, curved, rigid interface femtosecond laser-assisted capsulotomy specimens using 15 µJ pulse energy showed tags, bridges, rougher edges, and demarcation lines on the capsulotomy edges on SEM but subjectively estimated a more round shape on LM. FINANCIAL DISCLOSURES: Mr. Klaproth received travel reimbursements and/or lecture fees from Alcon Laboratories, Inc., Rayner Intraocular Lenses Ltd., and Oculus GmbH. Dr. Kohnen received travel reimbursements, grant support, and/or lecture fees from Alcon Laboratories, Inc., Abbott Medical Optics, Inc., Bausch & Lomb, Carl Zeiss Meditec AG, Neoptics AG, Rayner Intraocular Lenses Ltd., and Schwind eye-tech-solutions GmbH and Co. KG; he is a consultant to Alcon Laboratories, Inc., Carl Zeiss Meditec AG, Rayner Intraocular Lenses Ltd., and Schwind eye-tech-solutions GmbH and Co. KG. No other author has a financial or proprietary interest in any material or method mentioned.

Corneal decompensation and angle-closure glaucoma after upside-down implantation of an angle-supported anterior chamber phakic intraocular lens.

We present the case of a 27-year-old man with severe pain, loss of visual acuity, corneal edema, and high intraocular pressure (IOP) in 1 eye after bilateral Acrysof Cachet phakic intraocular lens (pIOL) implantation. Slitlamp examination was limited due to severe corneal edema, but anterior segment optical coherence tomography indicated upside-down implantation of the pIOL. The pIOL was explanted, which confirmed that the haptic indicator had been implanted counterclockwise. Postoperative treatment included antiinflammatory and antiglaucoma topical therapy. Follow-up monitoring showed decreasing corneal edema and normalized IOP. At 6 weeks, the corrected distance visual acuity was +0.1 logMAR, the IOP was within normal limits, and the cornea showed no signs of edema, but there was endothelial cell density loss. This case presents the preoperative and postoperative management of high IOP after pIOL implantation and illustrates the pitfalls of incorrect implantation of angle-supported anterior chamber IOLs with haptic angulation.

Dynamic positional change and defocus curve of a phakic foldable anterior-chamber angle-supported intraocular lens during accommodation.

OBJECTIVE: To evaluate movements of an anterior-chamber angle-supported phakic intraocular lens (PIOL) Cachet (Alcon, Fort Worth, Texas) and their influence on visual acuity during accommodation. DESIGN: Prospective case series. PARTICIPANTS: We included 54 eyes of 27 patients (15 female, 12 male; age, 38 ± 7.61 years; preoperative manifest spherical equivalent -8.7 ± 2.5 diopters [D]). METHODS: Evaluation of the PIOL's positional stability (distance to the corneal endothelium [M1] and the natural lens [M2]) as well as the pre- and postoperative anterior chamber depth (ACD) and pupil diameter (PD). Measurements were performed for accommodation stimuli ranging from -7 to +1 D in 1-D increments using optical coherence tomography (Visante OCT, Carl Zeiss Meditec, Jena, Germany). The respective defocus curve was evaluated using Early Treatment Diabetic Retinopathy Study charts. Statistical analysis included a Kolmogoroff-Smirnov test for parametric distribution, a Friedman- and consecutive Conover-Iman-Bonferroni test for detection of PD, ACD, and defocus curve differences from before to after the operation, a 1-sided t test for analysis of positional changes (ΔPD, ΔACD, and ΔM values compared with a zero stimulus position), and a regression analysis for the evaluation of influence of age, IOL diameter, and power on Δ-values. Significance was set at P = 0.05. MAIN OUTCOME MEASURES: Postoperative ΔM values. RESULTS: The PD, ΔPD, ACD, and ΔACD did not differ significantly between pre- and postoperative values. The ΔM1 and ΔM2 differed significantly from the zero-stimulus position for defocus stimuli of ≥-3 D and ≥-2D, respectively; mean ΔM1max was -0.09 ± 0.06 mm for -7-D stimulus; mean ΔM2max was -0.09±0.10 mm for -5-/-6-D stimulus. Apart from ΔPD, all Δ-values decreased with age. Visual acuity was significantly better postoperatively for defocus stimuli between 0 and -3 D. CONCLUSIONS: The anterior-chamber angle-supported PIOL changes its position during accommodation only marginally. The PIOL does not affect postoperative accommodation.

Three-year stability of an angle-supported foldable hydrophobic acrylic phakic intraocular lens evaluated by Scheimpflug photography.

PURPOSE: To examine the postoperative positional stability of a new angle-supported, hydrophobic acrylic phakic intraocular lens (pIOL). SETTING: Department of Ophthalmology, Goethe-University, Frankfurt am Main, Germany. METHODS: In this prospective nonrandomized clinical trial, eyes with moderate to high myopia had implantation of an angle-supported pIOL (AcrySof Cachet). Scheimpflug imaging was performed preoperatively and postoperatively at 1, 3, 6 to 12, and 24 to 36 months. The main outcome measures were the distance between the corneal endothelium and the IOL and between the IOL and the crystalline lens. The overall significance threshold was P = .05. RESULTS: Twenty-one of the 26 eyes (26 patients) evaluated were included in the statistical analysis. Analysis of variance showed no statistically significant differences in absolute endothelium-IOL or IOL-crystalline lens measurements at any postoperative visit. The mean endothelium-IOL distance was 2.05 mm +/- 0.25 (SD) at 1 month and 2.15 +/- 0.29 mm at 24 to 36 months and the mean IOL-crystalline distance, 0.92 +/- 0.23 mm and 0.86 +/- 0.22 mm, respectively. A 1-way t test showed a small but significant difference compared with zero in the overall change in the endothelium-IOL distance (mean 0.08 +/- 0.16 mm) and thus in the overall calculated anterior chamber depth (mean 0.07 +/- 0.08 mm); the difference was not significant for the IOL-crystalline lens change (mean -0.05 +/- 0.13 mm). CONCLUSION: The angle-supported foldable hydrophobic pIOL maintained adequate central clearance distances to the corneal endothelium and the natural crystalline lens over 3 years. FINANCIAL DISCLOSURE: Neither author has a financial or proprietary interest in any material or method mentioned. Additional disclosure is found in the footnotes.

Cataract surgery with implantation of an artificial lens.

BACKGROUND: Cataract surgery, the most frequently performed operative procedure worldwide, typically concludes with the implantation of an artificial intraocular lens (IOL) to correct aphakia (absence of the crystalline lens). METHOD: Selective literature review including current regulations, guidelines and recommendations for cataract surgery. RESULTS: The main symptom of cataract is loss of visual acuity, which usually progresses slowly. It can arise in one eye or both. There is a basic distinction between congenital and acquired cataracts. The probability of developing a cataract rises with age because of biochemical aging processes. The development of a cataract becomes highly likely from the sixth decade of life onward. CONCLUSIONS: As no effective medications for cataract are available at present, its current standard treatment is the removal of the clouded lens. In industrialized countries, this is usually done with ultrasound (phacoemulsification), followed by the implantation of an IOL.

Effect of intraocular lens asphericity on quality of vision after cataract removal: an intraindividual comparison.

PURPOSE: To determine the effect of intraocular lens (IOL) asphericity on quality of vision after cataract removal. DESIGN: Intraindividual, prospective, randomized clinical trial. PARTICIPANTS: Twenty-six cataract patients received 2, one-piece, blue-light-filtering hydrophobic acrylic IOLs each. METHODS: One eye was implanted with a spherical (SN60AT, Alcon) and the contralateral eye with an aspheric (SN60WF, Alcon) IOL with -0.2 mum spherical aberration (SA). All trial-specific measurements (corneal topography, wavefront sensing, high-contrast visual acuity [HCVA], contrast sensitivity [CS]) were performed 6 months after surgery. A paired Student t-test or Wilcoxon test was used to check intergroup differences. MAIN OUTCOME MEASURES: Absolute values and intraindividual differences (Delta(i)) of corneal and ocular higher order aberrations and best-corrected visual Strehl ratio based on the optical transfer function (BCVSOTF) values for virtual pupil diameters of 3, 4, 5, and 6 mm were computed. Photopic and mesopic HCVA, photopic, and high-mesopic CS as well as high-mesopic disability glare (DG) were measured using the Frankfurt-Freiburg Contrast and Acuity Test System. RESULTS: No intergroup difference of demographic data, pupillometry, and corneal aberrations were observed. Coma and trefoil root mean square and SA were significantly lower in the aspheric group resulting in higher BCVSOTF, mesopic HCVA, and photopic and high mesopic CS. All Delta(i) values with exception of photopic HCVA and DG indicated significantly better performance of the aspheric IOL. CONCLUSIONS: An aspheric IOL with -0.2 microm SA provide higher quality of vision than spherical IOL in terms of retinal image quality, mesopic HCVA and CS. FINANCIAL DISCLOSURE(S): Proprietary or commercial disclosures may be found after the references.

Incision sizes before and after implantation of SN60WF intraocular lenses using the Monarch injector system with C and D cartridges.

PURPOSE: To evaluate incision sizes for 6.0 mm optic hydrophobic acrylic intraocular lenses (IOLs) implanted with different injector systems and surgical techniques. SETTING: Department of Ophthalmology, Johann Wolfgang Goethe-University, Frankfurt, Germany. METHODS: In this prospective randomized trial of 100 cataract patients, hydrophobic acrylic IOLs (SN60WF) were implanted using 2 injector systems with 2 cartridges (Monarch II and Monarch III with C and D cartridges, respectively; Alcon) and 2 surgical techniques (direct implantation and wound-assisted docking implantation). Incision sizes were measured before and after phacoemulsification as well as before and after IOL implantation using a Tsuneoka microincision gauge. The Saphiro-Wilks test was performed to detect nonparametric distribution and the Kruskal-Wallis test, to test for significant differences between groups. RESULTS: The mean incision sizes (mm) at the 4 points of treatment with the Monarch III with the D cartridge were 1.98+/-0.07, 2.01+/-0.05, 2.42+/-0.07, and 2.51+/-0.05, respectively, with direct implantation and 1.92+/-0.06, 1.98+/-0.04, 2.02+/-0.11, and 2.09+/-0.11, respectively, with wound-assisted implantation. With the Monarch II with the C cartridge, the mean incision sizes were 2.17+/-0.06, 2.2+/-0.16, 2.77+/-0.11, and 2.86+/-0.11, respectively, with direct implantation and 2.12+/-0.10, 2.17+/-0.19, 2.19+/-0.09, and 2.28+/-0.08, respectively, with wound-assisted implantation. Postoperative incision sizes differed significantly from preoperative incision sizes and from each other (P<.05). CONCLUSION: With new injector systems and an appropriate docking implantation technique, foldable hydrophobic acrylic IOLs can be implanted through 2.0 mm tunnel incisions.

Basic knowledge of refractive surgery: correction of refractive errors using modern surgical procedures.

INTRODUCTION: Refractive ophthalmic surgery allows refractive errors to be corrected permanently in a safe, effective, and reliable way with few complications. METHODS: Selective literature review with special reference to the guidelines of the German Commission for Refractive Surgery. RESULTS: With a total of almost 18 million treatments performed to date, laser in-situ keratomileusis (LASIK) is the most commonly used refractive surgical procedure worldwide. Alternatives to LASIK include surface ablation procedures (PRK, LASEK, Epi-LASIK) and phakic intraocular lens implantation. If ocular accommodation is lost, removal of the crystalline lens and implantation of modern multifocal intraocular lenses (refractive lens exchange) provide an alternative means of correcting myopia, hyperopia and presbyopia. DISCUSSION: The treatment effect is maximized and complications kept to a minimum if strict inclusion criteria are applied and a high technical standard maintained during the procedure.