Christoph Russmann

First efficacy and safety study of femtosecond lenticule extraction for the correction of myopia Six-month results

PURPOSE: To prospectively study the feasibility of femtosecond lenticule extraction (FLE), a new method of refractive correction. SETTING: Department of Ophthalmology, Philipps University of Marburg and Helios Clinic, Erfurt, Germany. METHODS: A flap and a lenticule of intrastromal corneal tissue were simultaneously cut with a VisuMax femtosecond laser system. Next, the lenticule was manually removed and the flap repositioned. The target refraction in all cases was −0.75 diopter (D). RESULTS: All 10 myopic eyes in the initial treatment group completed the final 6‐month follow‐up. The mean patient age was 39 years. The mean spherical equivalent (SE) was −4.73 ± 1.48 (SD) preoperatively and −0.33 ± 0.61 D 6 months postoperatively. Ninety percent of eyes were within ±1.00 D and 40% were within ±0.50 D of the intended correction. No eye lost 2 or more Snellen lines. Corneal topography showed large, prolate optical zones. Aberrometry showed no significant induction of higher‐order aberrations. On a standardized questionnaire, all patients said they were very satisfied with the results. CONCLUSIONS: Preliminary results indicate that FLE is a promising new corneal refractive procedure to correct myopia.

Vector analysis of myopic astigmatism corrected by femtosecond refractive lenticule extraction

Purpose To evaluate the visual outcome of refractive lenticule extraction in eyes with myopic astigmatism using the Visumax femtosecond laser. Setting Department of Ophthalmology, HELIOS Klinikum Erfurt, Erfurt, Germany. Design Nonrandomized clinical trials. Methods The data set encompassed treatments of sphere and astigmatism. Vector analysis was performed to study the astigmatic results at each follow‐up visit at 1 week and 1, 3, and 6 months. Visual outcomes were analyzed for the 6‐month follow‐up period. Results The data evaluated was a complete set of refractive data of 182 treatments (87 left eyes, 95 right eyes). Efficacy, predictability, and safety with regard to astigmatic correction were comparable to the results with U.S. Food and Drug Administration–approved excimer lasers. At 6 months, the mean error ratio was 0.68 ± 0.75 (SD) and the mean correction ratio was 1.11 ± 0.69. There was slight astigmatic undercorrection (approximately 10%) over time. The residuum of the linear regression analysis of the predictability plot was approximately 0.4 diopter. Ninety‐six percent of the eyes had a corrected distance visual acuity (CDVA) of 20/20 or better; no eye had a CDVA worse than 20/32. Conclusion Femtosecond refractive lenticule extraction is an effective procedure for correcting myopic astigmatism. Financial Disclosure Drs. Sluyterman v. L. and Russmann are employees of and Drs. Blum and Kunert are investigators for Carl Zeiss Meditec AG, Jena, Germany.

Effect of a suction device for femtosecond laser on anterior chamber depth and crystalline lens position measured by OCT.

PURPOSE To investigate the position and stability of the crystalline lens after application of a suction device containing a contact lens and a vacuum unit for the treatment of presbyopia using a femtosecond laser. METHODS Twenty presbyopic (44.4+/-4.3 years) and 5 pre-presbyopic patients (31.6+/-3.8 years) were included. The anterior chamber depth, along with the position of the lens, was investigated before and after application of the suction device with optical coherence tomography (Visante OCT; Carl Zeiss Meditec AG). The type of suction device is routinely used for femtosecond LASIK with the VisuMax laser (Carl Zeiss Meditec AG). RESULTS In both groups, there was a reduction in anterior chamber depth of approximately 700 microm due to the suction device, and the anterior chamber depth achieved was stable. The maximum variation was 160 microm. At the periphery of the crystalline lens, there were movements up to 310 microm axially and 470 microm laterally. CONCLUSIONS The study proves that once the suction device has been applied, the crystalline lens is stable enough to undergo presbyopic laser therapy. However, the reduction in anterior chamber depth induced by the suction device showed significant individual variation. The exact position of the lens should therefore be measured immediately before laser surgery.

Automated Retinal Image Analysis for Evaluation of Focal Hyperpigmentary Changes in Intermediate Age-Related Macular Degeneration

Purpose To develop and evaluate a software tool for automated detection of focal hyperpigmentary changes (FHC) in eyes with intermediate age-related macular degeneration (AMD). Methods Color fundus (CFP) and autofluorescence (AF) photographs of 33 eyes with FHC of 28 AMD patients (mean age 71 years) from the prospective longitudinal natural history MODIAMD-study were included. Fully automated to semiautomated registration of baseline to corresponding follow-up images was evaluated. Following the manual circumscription of individual FHC (four different readings by two readers), a machine-learning algorithm was evaluated for automatic FHC detection. Results The overall pixel distance error for the semiautomated (CFP follow-up to CFP baseline: median 5.7; CFP to AF images from the same visit: median 6.5) was larger as compared for the automated image registration (4.5 and 5.7; P < 0.001 and P < 0.001). The total number of manually circumscribed objects and the corresponding total size varied between 637 to 1163 and 520,848 pixels to 924,860 pixels, respectively. Performance of the learning algorithms showed a sensitivity of 96% at a specificity level of 98% using information from both CFP and AF images and defining small areas of FHC (“speckle appearance”) as “neutral.” Conclusions FHC as a high-risk feature for progression of AMD to late stages can be automatically assessed at different time points with similar sensitivity and specificity as compared to manual outlining. Upon further development of the research prototype, this approach may be useful both in natural history and interventional large-scale studies for a more refined classification and risk assessment of eyes with intermediate AMD. Translational Relevance Automated FHC detection opens the door for a more refined and detailed classification and risk assessment of eyes with intermediate AMD in both natural history and future interventional studies.

In vivo Imaging with a Fundus Camera in a Rat Model of Laser-Induced Choroidal Neovascularization

Purpose: To investigate the use of imaging and quantitative measurement capabilities of a modified fundus camera in a rat model of laser-induced choroidal neovascularization. Methods: Following induction of experimental choroidal neovascularization, Dark Agouti rats underwent serial in vivo imaging with a fundus camera (FF450plus, Carl Zeiss MediTec, Jena, Germany), including color, reflectance and fluorescence imaging. Results: A custom-made setting allowed high-resolution imaging. Change of fluorescence intensity following intravenous or intravitreal dye injection could be quantitatively monitored over time. Hardware binning resulted in an improved signal-to-noise ratio and a reduction of flash light intensity. Simultaneous fluorescence imaging following injection of two different dendritic polygylcerol sulfate dyes could be demonstrated. Conclusion: This study demonstrates the use and optimizations of a fundus camera for various in vivo imaging modalities in rats. Molecular imaging of the eye may allow for better insights into cellular dysfunction and optimization of therapeutic strategies.