Thomas Kohnen

Thomas Kohnen
Goethe-Universität Frankfurt am Main ·  Department of Ophthalmology

Prof. Dr. med.

About

682
Publications
31,531
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10,424
Citations

Publications

Publications (682)
Article
To plan and execute a successful and safe cataract surgery one must conduct a structured, goal- and patient-oriented examination. The medical history provides crucial information regarding the planning of the anesthetic procedure, lens selection and possible intraoperative complications. Visual acuity and refraction measurements are essential for b...
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Purpose To investigate the changes in vitreous inflammatory and angiogenic cytokine levels, primarily interleukin-(IL)-6, following intravitreal injection of the 0.19 mg fluocinolone acetonide (FAc, ILUVIEN®) implant in patients with diabetic macular edema. Methods A single-center phase IV study involving 12 patients’ eyes with diabetic macular ed...
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Zusammenfassung Die Kataraktoperation stellt mit etwa 800 000 Operationen pro Jahr eine der häufigsten Operationen in Deutschland dar; aufgrund des demografischen Wandels ist von einem Anstieg in den nächsten Jahrzehnten auszugehen. Daneben erweitern sich die diagnostischen und operativen Möglichkeiten. Ziel dieses Beitrags ist, eine strukturierte,...
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Background The ongoing expansion of the cosmetic armamentarium of facial rejuvenation fails to uncover the inherent risks of cosmetic interventions. Informed consent to all risks of cosmetic filler injections and potential sequelae, including ocular and neurological complications, should be carefully ensured. We present two cases of complications f...
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Purpose To evaluate formulas for intraocular lens (IOL) calculation in silicone oil (SO) filled eyes. Design Retrospective, consecutive case series Methods We conducted our study at the Department of Ophthalmology, Goethe University, Frankfurt, Germany and included SO filled eyes that received SO removal combined with phacoemulsification and IOL...
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Purpose: To determine the accuracy and precision of corneal lenticule creation with a new solid-state femtosecond laser in a porcine eye model. Methods: Corneal lenticule creation was performed using a new solid-state femtosecond laser on 60 porcine eyes with 10 subgroups. Optical coherence tomography images were acquired immediately after laser...
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Zusammenfassung Hintergrund Die Deutsche Ophthalmologische Gesellschaft (DOG) erfasst regelmäßig die wissenschaftlichen Aktivitäten der augenheilkundlichen Forschungseinrichtungen in Deutschland. Ziel der Arbeit Mit dieser Publikation will die DOG die Leistungsfähigkeit der wissenschaftlichen Augenheilkunde in Deutschland transparent machen und d...
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Purpose Amblyopia with eccentric fixation, especially when not diagnosed early, is a therapeutic challenge, as visual outcome is known to be poorer than in amblyopia with central fixation. Consequently, treatment after late diagnosis is often denied. Electronic monitoring of occlusion provides us the chance to gain first focussed insight into age-d...
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Purpose To investigate short-term (3 months follow-up) changes in visual quality following Descemet membrane endothelial keratoplasty (DMEK) for Fuchs endothelial dystrophy (FED). Methods In this prospective institutional case series, 51 patients that underwent DMEK for FED were included. Assessment included the Quality of Vision (QoV) questionnai...
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Purpose Filler injections for aesthetic purposes are very popular, but can have far-reaching and irreversible consequences. This report describes the course of a patient with devastating complications after glabellar hyaluronic acid injection, their pathomechanism, management and outcome. Observations A healthy, 43-year-old woman underwent her fir...
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Studying anterior lens capsule cutting edge profiles from femtosecond laser-assisted capsulotomy procedures performed before and after lens fragmentation. Twenty eyes (10 patients) with age-related cataract underwent femtosecond laser-assisted surgery (FLACS) using the Ziemer Z8 platform. First step of laser surgery was either capsulotomy (group fi...
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Purpose: To investigate the self-rated quality of vision (SQV) and optical phenomena intensity of three diffractive multifocal intraocular lenses (MIOLs). Setting: Department of Ophthalmology, Goethe University Frankfurt, Germany. Design: Prospective comparative case series. Methods: Patients who had bilateral implantation of a diffractive e...
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Purpose: To investigate long-term complications after pediatric cataract surgery with implantation of a heparin-coated polymethyl methacrylate intraocular lens (PMMA IOL) and posterior continuous curvilinear capsulorhexis (PCCC) with anterior vitrectomy vs PCCC without anterior vitrectomy with optic capture buttonholing. Setting: Department of O...
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Purpose To evaluate the potential impact of rebubbling on the anterior segment parameters and refractive outcomes in patients with graft detachment following uneventful DMEK for Fuchs endothelial dystrophy (FED). Methods Retrospective institutional cohort study of comparing 34 eyes of 31 patients with rebubbling for graft detachment following Desc...
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Purpose: To evaluate visual performance and patient-reported outcomes after bilateral implantation of a new nondiffractive wavefront-shaping extended depth-of-focus (EDoF) intraocular lens (IOL). Setting: Department of Ophthalmology, Goethe University, Frankfurt, Germany. Design: Prospective, single-arm, single-center study. Methods: Patient...
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Purpose To determine the effect of lockdown on medical care, with the example of ophthalmology. Methods Patients in a period during the first lockdown were compared to a non-lockdown period, with a total of 12 259 patients included in an observational study. Changes in different areas (elective, emergency, inpatients, surgeries) and eye care subspe...
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Purpose: To compare agreement of anterior segment parameter measurements using an intraoperative optical coherence tomography (iOCT) of a femtosecond laser (LenSx) during interface docking to the eye to preoperative Scheimpflug-tomography (Pentacam AXL) and swept-source optical coherence tomography (IOL Master 700). Setting: Department of Ophtha...
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Purpose: To evaluate factors that influence postoperative satisfaction in patients with diffractive EDOF and multifocal IOLs. Setting: Department of Ophthalmology, Goethe University Frankfurt, Germany. Design: Observational case study. Methods: Patients were evaluated after implantation of a diffractive EDOF (Symfony, J&J, USA; AT LARA, CZM,...
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Purpose To analyze refractive and topographic changes secondary to Descemet membrane endothelial keratoplasty (DMEK) in pseudophakic eyes with Fuchs’ endothelial dystrophy (FED). Methods Eighty-seven pseudophakic eyes of 74 patients who underwent subsequent DMEK surgery for corneal endothelial decompensation and associated visual impairment were i...
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Purpose: To compare the effective lens position (ELP), anterior chamber depth (ACD) changes, and visual outcomes in patients with and without pseudoexfoliation syndrome (PEX) after cataract surgery. Design: Prospective, randomized, fellow-eye controlled clinical case series. Methods: This prospective comparative case series enrolled 56 eyes of...
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Background Survey by the commission for cross-sectoral ophthalmology, as a joint commission of the German Ophthalmological Society (DOG) and the Professional Association of German Ophthalmologists (BVA) on the effects of the SARS-CoV‑2 pandemic on ophthalmological patient care in Germany.Methods Online-based survey.ResultsA total of 1190 questionna...
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Diabetic retinopathy (DR) is an inflammatory condition that affects the posterior of the eye; yet, there are limited published data on techniques measuring the expression of growth and inflammatory factors (GIF) from the posterior segment. The purpose of the current study was two-fold: to sample the vitreous fluid from the eyes of patients with DR...
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Myopia is the most common refractive error. Surgical correction with laser is possible. LASIK and SMILE are the techniques currently most used. Aim of the study was to compare changes in corneal volume and thickness after the respective laser treatment. 104 eyes of 52 patients were matched based on refractive error into two equally sized groups, ei...
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Zusammenfassung Um 1970 herum wurde erstmals ein Schneidegerät, in welches ein Infusions- und ein Aspirationskanal integriert wurden – der „vitreous infusion suction cutter“ (V.I.S.C) –, standardmäßig für die Entfernung des Glaskörpers angewandt. Schneidesysteme haben sich von da an immer weiter entwickelt. Schallenergie blieb lange den Vorderabsch...
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Purpose: To evaluate a ray-tracing formula for intraocular lens (IOL) calculation of diffractive extended depth of focus IOLs after myopic laser in situ keratomileusis (LASIK) compared to formulas from an established online calculator. Methods: This retrospective, consecutive case series included patients after cataract surgery with implantation...
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Zusammenfassung Hintergrund Die Ophthalmoskopie ist Bestandteil des medizinischen Curriculums, jedoch das Vermitteln der Inhalte oft unbefriedigend, da ein systematisches Lernen von Pathologien und deren Behandlungen dadurch erschwert ist, dass oftmals das passende Patientengut nicht zur Verfügung steht und dadurch gesunde Studenten einander unter...
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Zusammenfassung Die SMILE (small incision lenticule extraction) zählt zu den Verfahren der refraktiven Lentikel-Extraktion und hat sich im letzten Jahrzehnt zu einem etablierten Bestandteil des modernen refraktivchirurgischen Spektrums entwickelt. Dieser Beitrag gibt einen Überblick über Patientenselektion, Operationsmethode, mögliche Komplikatione...
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Purpose To evaluate the refractive and visual outcome of patients with misaligned toric IOLs after operative realignment, with and without back-calculation of the toric axis after implantation of the IOL. Design Institutional, retrospective case-control study Methods This is a retrospective case series of 39 patients who underwent a second operat...
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Refractive lenticule extraction is a corneal surgical technique that uses a femtosecond laser exclusively to create an intrastromal refractive lenticule for the correction of myopia and myopic astigmatism. In small incision lenticule extraction (SMILE) the generated refractive lenticule is subsequently extracted through a small incision. The report...
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Keratoconus is a progressive ectatic corneal disorder, which can result in severe visual impairment. The new ABCD keratoconus classification system allows differentiated description of the disease. Aim of the study was to evaluate the components of this novel staging system (ARC, PRC, thinnest pachymetry) as well as topometric indices, deviation of...
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Purpose: To evaluate the visual performance after bilateral implantation of a toric diffractive aspheric multifocal intraocular lens (IOL) with a +2.17 diopters (D) (60 cm) intermediate and a +3.25 D (40 cm) addition (add) power. Methods: This prospective single-arm study was conducted at the Department of Ophthalmology, Goethe University, Frank...
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Background Survey by the commission for cross-sectoral ophthalmology, as a joint commission of the German Ophthalmological Society (DOG) and the Professional Association of German Ophthalmologists (BVA) on the effects of the SARS-CoV‑2 pandemic on ophthalmological patient care in Germany.Methods Online-based survey.ResultsA total of 1190 questionna...
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Purpose: To assess endothelial cell loss (ECL) rate and collect safety data in patients with AcrySof L-series Cachet phakic intraocular lens (pIOL) up to 10 years post-implantation. Setting: Clinical settings in the United States, European Union, and Canada. Design: Nonrandomized, observational, open-label safety study. Methods: Central and...
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Early ophthalmological care of patients in intensive care with SARS-CoV‑2 (Severe-Acute-Respiratory-Syndrom-Corona-Virus-2) infections is very time-consuming; however, this approach might prevent other ophthalmological diseases, such as lagophthalmos. There is no difference in ophthalmological treatment between SARS-CoV‑2 positive and other intensi...
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The SARS-CoV‑2 pandemic poses major challenges for the entire medical care system. Especially in maximum care clinical facilities, a higher exposure to potentially infectious patients or positively tested COVID-19 patients is to be expected. A hospital facility concept was developed in the Department of Ophthalmology, Goethe University, Frankfurt a...
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Background: To evaluate intraocular lens (IOL) calculation formulas provided by an online calculation tool from the American Society of Cataract and Refractive Surgery (ASCRS) for an extended depth-of-focus (EDOF) IOL after previous myopic laser in situ keratomileusis (LASIK). Setting: Department of Ophthalmology, Goethe University Frankfurt, Ge...
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This review article focusses on the management of enhancements after corneal refractive laser surgery. Fundamental issues regarding enhancement embrace identification of the underlying reason for postoperative ametropia, assurance of stability of refraction, type of primary refractive laser treatment and thorough evaluation of the given anatomical...
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After an uneventful intravitreal injection (IVI) of Ocriplasmin in a patient with reduced visual acuity due to vitreomacular traction (VMT) and a small macular hole, retinal detachment occurred within a few days after the operation. Although retinal detachment is known as a risk factor of IVI this case is noteworthy: an excessive reaction occurred...
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Zusammenfassung In den 30 Jahren seit Beginn der laserassistierten Hornhautchirurgie sind die Techniken zur Korrektur von Fehlsichtigkeiten weiterentwickelt und verbessert worden. Dennoch muss ein Teil der Patienten nachkorrigiert werden, u. a. wegen residualer Refraktionsfehler. Darüber soll im Folgenden berichtet werden.
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Purpose: To compare the efficacy and safety of femtosecond laser-assisted cataract surgery (FLACS) with conventional cataract surgery (CCS). Setting: Department of Ophthalmology, Goethe-University, Frankfurt am Main, Germany. Design: Meta-analysis. Methods: PubMed, Cochrane Library, and EMBASE were systematically searched for studies compari...
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Purpose: To determine improvement of near visual acuity by bilateral multifocal aspheric LASIK treatments in presbyopic patients. Setting: Goethe-University, Frankfurt, Germany. Design: Prospective, non-randomized trial. Methods: Thirty presbyopic patients underwent laser in situ keratomileusis (LASIK) treatment with a multifocal aspheric ab...
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A congenital cataract is a rare disorder, which is associated with a high risk of amblyopia. Ophthalmologists are faced with many diagnostic and surgical challenges in the management of this disease. Older children can undergo primary treatment with an intraocular lens, whereas children younger than 12 months of age usually initially remain aphakic...
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Zusammenfassung Wir berichten über eine 27-jährige Patientin mit Pigmentdispersionssyndrom und Hornhautdekompensation in beiden Augen nach Implantation eines Irisimplantates (BrightOcular, Anaheim, CA, USA) zur Änderung der Augenfarbe. Drei Jahre nach Implantation der künstlichen Iris an einer Augenklinik in Indien erfolgte die konsekutive Entfernu...
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Purpose: To implant a small-aperture intraocular lens (IOL) (IC-8) in eyes with severe corneal irregularities to reduce higher-order aberrations and provide better central visual acuity. Setting: University Hospital, LMU Munich, Germany. Design: Prospective nonrandomized interventional case series. Methods: Eyes with severe corneal irregular...
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Purpose: Evaluate the repeatability and validity of total corneal power measurements (TK) obtained with a recently introduced optical biometer (IOL Master 700, Zeiss, Germany) to a Scheimpflug device (Pentacam, Oculus, Germany). Setting: Department of Ophthalmology, Ludwig-Maximilians-University, Munich, Germany DESIGN:: Prospective randomized c...
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Purpose: To evaluate differences in effective lens position (ELP) based on the lens design. Intraocular lenses (IOL) with plate-haptic, c-loop haptic and a rhexis fixated lens were compared. Setting: Department of Ophthalmology, Ludwig-Maximilians-University, Munich, Germany. Department of Ophthalmology, Goethe-University, Frankfurt, Germany. no...
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Purpose: To evaluate the safety and efficacy of femtosecond (FS) laser-assisted in situ keratomileusis (LASIK) combined with accelerated corneal crosslinking (LASIK Xtra) compared to conventional FS-LASIK (convLASIK) in high myopic patients. Design: Prospective, randomized, fellow-eye controlled, clinical trial. Setting: Department of Ophthalm...
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Purpose: To evaluate the defocus curves of 4 presbyopia-correcting intraocular lenses (IOLs). Setting: Department of Ophthalmology, Goethe University, Frankfurt, Germany. Design: Prospective case series. Methods: Patients included in the study had bilateral surgery with implantation of diffractive panfocal, diffractive trifocal, segmental re...
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Purpose: To evaluate surgically induced astigmatism (SIA) of temporal clear corneal incisions (CCIs) on anterior and posterior corneal curvature after femtosecond laser-assisted cataract surgery (FLACS) using Scheimpflug tomographic measurements. Setting: Department of Ophthalmology, Goethe University, Frankfurt am Main, Germany. Design: Prosp...
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We assessed the feasibility of an epidemiological study on the risk of radiation-related lens opacities among interventional physicians in Germany. In a regional multi-centre pilot study associated with a European project, we tested the recruitment strategy, a European questionnaire on work history for the latter dosimetry calculation and the endpo...
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Die vorliegende Übersichtsarbeit gibt einen Einblick in refraktive Oberflächenverfahren, insbesondere der PRK und trans-PRK. Aktuelle Aspekte werden dargestellt und Nebenwirkungen sowie Risiken diskutiert.
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Die Laser in situ Keratomileusis (LASIK) stellt weltweit den Goldstandard der laserchirurgischen Verfahren zur dauerhaften Korrektur von Brechkraftfehlern dar. Durch den technologischen Fortschritt und die zunehmende chirurgische Expertise konnten in der letzten Dekade die refraktive Genauigkeit dieser Methode weiter verfeinert und die Risiken gese...
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New digital approaches allow stereovision to be assessed with greater precision than current clinical stereo tests. Those current tests present a relatively narrow range of stimulus disparities in coarsely quantized steps. With dichoptic treatments for amblyopia emerging, more accurate assessment of especially coarse stereopsis becomes increasingly...
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Auf dem Fundament einer sorgfältigen präoperativen Anamnese, einer gründlichen klinischen Untersuchung und apparativer Diagnostik und unter Berücksichtigung entsprechender Ein- und Ausschlusskriterien stellt die Implantation phaker Intraokularlinsen eine sichere Option zur Korrektur von Augen mit zugrundeliegender höherer und auch niedriger Ametrop...
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To evaluate the required cumulative dissipated energy (CDE) to fragment the crystalline lens in femtosecond laser–assisted cataract surgery (FLACS) in relation to lens density and lens thickness. Consecutive eyes that underwent FLACS between September 2014 and March 2017 by a single surgeon using in all cases the same femtosecond laser and phacoemu...
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A 23-year-old male patient presented with very mild visual disturbances, but a distinct prominence of the optic discs, more pronounced in the right than in the left eye. The ophthalmic symptoms initially seemed trivial, but a large-scale interdisciplinary workup later identified them as the presenting symptoms of sarcoidosis affecting lung and eyes...
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Purpose: To evaluate the characteristics of preoperative and postoperative astigmatism in patients having Descemet membrane endothelial keratoplasty (DMEK). Setting: Department of Ophthalmology, Goethe University, Frankfurt, Germany. Design: Retrospective case series. Methods: Measurements were obtained using a Scheimpflug camera (Pentacam A...
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Purpose: To evaluate Scheimpflug corneal densitometry (CD) in patients undergoing secondary Descemet membrane endothelial keratoplasty (DMEK) after previous Descemet stripping automated endothelial keratoplasty or DMEK surgery. Methods: This was a retrospective institutional case series of 37 eyes of 37 patients. Two secondary DMEK groups, group...
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Wir berichten von einem Patienten mit epithelialer Hyperplasie, peripheren Haze und Regression nach hyperoper transPRK außerhalb des KRC(Kommission für refraktive Chirurgie)-Grenzbereichs. Ein Jahr postoperativ erfolgten eine Retreatment-PRK beidseits und eine Narbenabrasio links. Dennoch zeigten sich erneute Narbenbildung, Haze und Regression. Ein...
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Purpose: To evaluate the visual performance of an extended depth of focus (EDOF) intraocular lens (IOL) for patient selection. Methods: This prospective non-comparative case series evaluated fifty-two eyes (26 patients) after bilateral implantation of the Tecnis Symfony IOL. Exclusion criteria were previous ocular surgeries, corneal astigmatism...
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Purpose: To analyze changes in corneal densitometry 3 months after accelerated corneal collagen cross-linking (CXL) measured with Scheimpflug tomography. Methods: In this study we reviewed charts and anterior segment data of patients who had undergone accelerated pulsed epithelium-off CXL (30 mW/cm2for 4 min, 8 min total radiation time) for trea...