Publications by authors named "Karsten Hufendiek"

16 Publications

  • Page 1 of 1

[Epidemiology and treatment of retinopathy of prematurity. The Hannover data in the Retina.net ROP registry from 2001-2017].

Ophthalmologe 2021 Nov 22. Epub 2021 Nov 22.

Universitätsklinik für Augenheilkunde, Medizinische Hochschule Hannover, Carl-Neuberg-Str. 1, 30625, Hannover, Deutschland.

Background: The Retina.net ROP registry documents data of preterm infants developing stages of retinopathy of prematurity (ROP) that need ROP treatment. The aim of this analysis was to investigate data regarding epidemiology, therapy and changes over time (15 years) in a single participating center (Hannover Medical School, MHH).

Methods: Analysis of data of infants treated for ROP at a single center over time (birth 2001-2016, ROP treatment in 2002-2017).

Results: Overall, 65 infants were treated (23 female). In 11 infants (16.9%) ROP screening was conducted externally and infants were transferred to the MHH for ROP treatment. Between 2006 and 2016, incidence of ROP requiring treatment among infants screened for the development of ROP was 4.1%. Mean gestational age was 25.7 weeks (standard deviation, SD 1.8), mean birth weight 763 g (SD 235), postmenstrual age at treatment 38.2 weeks (SD 3.2), postnatal age 12.4 weeks (SD 3.2). There was no significant change in parameters over time. ROP zone II, stage 3+ was most frequently treated (57 eyes of 31 infants). 58 infants were treated with laser (114 eyes), 7 infants were treated with anti-VEGF (bevacizumab, bilateral, 14 eyes) from 2014 onwards. Retreatment due to recurrence of ROP was necessary in one infant after initial laser coagulation. Infants with ROP requiring treatment often presented with neonatal comorbidities, ventilation in more than 90%, bronchopulmonary dysplasia, and received transfusions.

Conclusion: This is the first monocentric analysis over 15 years originating from the Retina.net ROP registry. In this cohort we see a change in ROP therapy from laser coagulation to anti-VEGF (bevacizumab) from 2014 onwards, demographic data and treatment parameters remained relatively stable over time.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s00347-021-01528-9DOI Listing
November 2021

Computer-Assisted Secondary Orbital Reconstruction.

Craniomaxillofac Trauma Reconstr 2021 Mar 9;14(1):29-35. Epub 2020 Jul 9.

Department of Oral-, Maxillo- and Plastic Facial Surgery, Heinrich-Heine-University Duesseldorf, Duesseldorf, Germany.

Study Design: This study presents a case-control study of 33 patients who underwent secondary orbital reconstruction, evaluating techniques and outcome.

Objective: Adequate functional and aesthetical appearance are main goals for secondary orbital reconstruction. Insufficient premorbid orbital reconstruction can result in hypoglobus, enophthalmos, and diplopia. Computer-assisted surgery and the use of patient-specific implants (PSIs) is widely described in the literature. The authors evaluate the use of selective laser-melted PSIs and hypothesize that PSIs are an excellent option for secondary orbital reconstruction.

Methods: The sample was composed of 33 patients, previously treated with primary orbital reconstruction, presenting themselves with indications for secondary reconstruction (i.e. enophthalmos, diplopia, or limited eye motility). Computed tomography and/or cone beam data sets were assessed before and after secondary reconstruction comparing intraorbital volumes, infraorbital angles, and clinical symptoms. Clinical outcomes were assessed using a standardized protocol.

Results: Results show a significant change in intraorbital volumes and a reduction of clinical symptoms after secondary reconstruction.

Conclusions: Outcomes of this study suggest that secondary orbital reconstruction can be performed routinely using selective laser-melted PSIs and titanium spacers.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1177/1943387520935004DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7868513PMC
March 2021

Clinical Heterogeneity in Autosomal Recessive Bestrophinopathy with Biallelic Mutations in the Gene.

Int J Mol Sci 2020 Dec 8;21(24). Epub 2020 Dec 8.

Zentrum für Seltene Netzhauterkrankungen, AugenZentrum Siegburg, MVZ Augenärztliches Diagnostik- und Therapiecentrum Siegburg GmbH, Europaplatz 3, 53721 Siegburg, Germany.

Autosomal recessive bestrophinopathy (ARB) has been reported as clinically heterogeneous. Eighteen patients (mean age: 22.5 years; 15 unrelated families) underwent ophthalmological examination, fundus photography, fundus autofluorescence, and optical coherence tomography (OCT). Molecular genetic testing of the gene was conducted by the chain-terminating dideoxynucleotide Sanger methodology. Onset of symptoms (3 to 50 years of age) and best-corrected visual acuity (0.02-1.0) were highly variable. Ophthalmoscopic and retinal imaging defined five phenotypes. Phenotype I presented with single or confluent yellow lesions at the posterior pole and midperiphery, serous retinal detachment, and intraretinal cystoid spaces. In phenotype II fleck-like lesions were smaller and extended to the far periphery. Phenotype III showed a widespread continuous lesion with sharp peripheral demarcation. Single (phenotype IV) or multifocal (phenotype V) vitelliform macular dystrophy-like lesions were observed as well. Phenotypes varied within families and in two eyes of one patient. In addition, OCT detected hyperreflective foci (13/36 eyes) and choroidal excavation (11/36). Biallelic mutations were identified in each patient, six of which have not been reported so far [c.454C>T/p.(Pro152Ser), c.620T>A/p.(Leu207His), c.287_298del/p.(Gln96_Asn99del), c.199_200del/p.(Leu67Valfs*164), c.524del/p.(Ser175Thrfs*19), c.590_615del/p.(Leu197Profs*26)]. -associated ARB presents with a variable age of onset and clinical findings, that can be categorized in 5 clinical phenotypes. Hyperreflective foci and choroidal excavation frequently develop as secondary manifestations.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3390/ijms21249353DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7763028PMC
December 2020

Postinfectious Onset of Myasthenia Gravis in a COVID-19 Patient.

Front Neurol 2020 6;11:576153. Epub 2020 Oct 6.

Department of Neurology, Hannover Medical School, Hanover, Germany.

We report the case of a young woman with postinfectious onset of myasthenia gravis after COVID-19 with mild respiratory symptoms and anosmia/ageusia 1 month before admission to our neurological department. Patient data were derived from medical records of Hannover Medical School, Germany. Written informed consent was obtained from the patient. The 21-year-old female patient presented with subacute, vertically shifted double vision evoked by right sided partial oculomotor paresis and ptosis. About 4 weeks earlier she had suffered from mild respiratory symptoms, aching limbs and head without fever, accompanied by anosmia/ageusia. During the persistence of the latter symptoms for around 10 days the patient had already noticed "tired eyes" and fluctuating double vision. Clinical assessment including a positive test with edrophonium chloride and increased acetylcholine receptor antibodies related the ocular manifestation etiologically to myasthenia gravis. Antibodies (IgA/IgG) against SARS-CoV-2 using three different serological tests (Abbott, DiaSorin, Euroimmun) were detected in serum suggesting this specific coronavirus as previously infectious agent in our patient. The myasthenic syndrome was treated successfully with intravenous immunoglobulins and oral pyridostigmine. This is the first case presentation of postinfectious myasthenia gravis as neurological complication in a COVID-19 patient.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3389/fneur.2020.576153DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7573137PMC
October 2020

[Pachymetry with a video slit lamp].

Ophthalmologe 2021 Feb;118(2):162-168

Universitätsklinik für Augenheilkunde der Medizinischen Hochschule Hannover, Hannover, Deutschland.

Background And Objective: Presentation and application of a method for pachymetry with the slit lamp based on the concept of a defined optical section.

Methods And Patients: The visible width of an optical section on slit lamp examination with a 45° angle between the slit beam and the central corneal surface was determined in 103 eyes (68 with glaucoma and 35 in patients with keratoconus). The measurements were compared to the pachymetric values previously determined elsewhere for these eyes in order to establish a proportionality factor for calculation of corneal thickness from slit lamp measurements.

Results: From a linear regression between the external pachymetry and visible width of the optical section in the split lamp, 1.71 was determined to be the factor of proportionality. Applying this factor to single measurements, 82 out of 103 eyes had a maximum difference of 40 µm compared to the external pachymetric values.

Conclusion: Based on a defined optical section at the slit lamp, clinically relevant estimates can be made for central corneal thickness in diseases, such as glaucoma or keratoconus. The difference to the externally measured pachymetric values was within the range of diurnal changes in corneal thickness for 80% of the eyes. Similar to other pachymetric procedures, the reliability of determination of the corneal thickness with the slit lamp also increases when applied intraindividually or for the same eye in the course of time.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s00347-020-01108-3DOI Listing
February 2021

Resolving the dark matter of ABCA4 for 1054 Stargardt disease probands through integrated genomics and transcriptomics.

Genet Med 2020 07 20;22(7):1235-1246. Epub 2020 Apr 20.

Bartiméus Diagnostic Center for Complex Visual Disorders, Zeist, The Netherlands.

Purpose: Missing heritability in human diseases represents a major challenge, and this is particularly true for ABCA4-associated Stargardt disease (STGD1). We aimed to elucidate the genomic and transcriptomic variation in 1054 unsolved STGD and STGD-like probands.

Methods: Sequencing of the complete 128-kb ABCA4 gene was performed using single-molecule molecular inversion probes (smMIPs), based on a semiautomated and cost-effective method. Structural variants (SVs) were identified using relative read coverage analyses and putative splice defects were studied using in vitro assays.

Results: In 448 biallelic probands 14 known and 13 novel deep-intronic variants were found, resulting in pseudoexon (PE) insertions or exon elongations in 105 alleles. Intriguingly, intron 13 variants c.1938-621G>A and c.1938-514G>A resulted in dual PE insertions consisting of the same upstream, but different downstream PEs. The intron 44 variant c.6148-84A>T resulted in two PE insertions and flanking exon deletions. Eleven distinct large deletions were found, two of which contained small inverted segments. Uniparental isodisomy of chromosome 1 was identified in one proband.

Conclusion: Deep sequencing of ABCA4 and midigene-based splice assays allowed the identification of SVs and causal deep-intronic variants in 25% of biallelic STGD1 cases, which represents a model study that can be applied to other inherited diseases.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41436-020-0787-4DOI Listing
July 2020

Trajectory-guided biopsy of orbital tumor - Technology, principal considerations and clinical implementation.

J Craniomaxillofac Surg 2018 Jun 31;46(6):994-1000. Epub 2018 Mar 31.

Department for Oral and Maxillofacial Surgery, University Hospital Duesseldorf, Duesseldorf, Germany.

Intraorbital space-occupying lesions always pose a challenge, both in terms of definite surgical removal as well as preoperative sampling for histopathological examination. Despite the use of modern high-resolution imaging techniques, the dignity of orbital lesions can often not be determined with sufficient certainty preoperatively. As the amount and complexity of treatment possibilities continue to increase, detailed diagnostics in advance of treatment choice are essential. Histological classification of orbital lesions can still be considered the gold standard for reliable diagnoses, leading to appropriate treatment. Over recent years minimally invasive surgical approaches have gained more importance in the treatment and diagnosis of cranio-maxillo-facial tumor and trauma. The aim of our study was to adapt and establish a precise procedure for orbital biopsies. 23 patients suffering from space-occupying lesions of unknown dignity were included. Trajectory-guided procedures were pre-planned for all cases. In most cases minimally invasive procedures were suitable for taking biopsies of the orbit. For only two patients a conventional, non-minimally invasive, lateral orbitotomy had to be performed. Further evaluation of the presented procedure demonstrates clearly that trajectory-guided biopsies of the orbit can be performed correctly and effectively, regardless of the suspected lesion's size.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.jcms.2018.03.017DOI Listing
June 2018

Classification and characterization of acute macular neuroretinopathy with spectral domain optical coherence tomography.

Int Ophthalmol 2018 Dec 13;38(6):2403-2416. Epub 2017 Oct 13.

Department of Ophthalmology, University Medical Center Regensburg, Regensburg, Germany.

Purpose: To classify and characterize AMN lesions with SD-OCT during a follow-up as long as 5 years.

Methods: Retrospective study of 14 patients (18 eyes) with special focus on SD-OCT. We measured thickness of inner nuclear layer (INL), outer retinal layer (ONL), and hyperreflective band at baseline and during follow-up. AMN lesions were classified as type 1 and type 2.

Results: Of 14 patients (six males, eight females, mean age 29.7 years), three patients (four eyes) had type 1 and nine (12 eyes) had type 2. Two patients did not meet the criteria for AMN type 1 or 2 and were therefore classified as new subtype of AMN. In all patients, statistically significant thinning of ONL and INL was observable. Mean ONL of all patients was 90.2 ± 7.81 and 72.3 ± 15.64 μm (p < 0.05) during follow-up; mean INL was 54.4 ± 10.71 and 37.5 ± 6.18 μm (p < 0.05) in the course. In the subgroup analysis in AMN type 2, the thinning of both ONL and INL was also statistically significant (mean ONL: 87.4 ± 6.02 and 71.6 ± 12.7 μm (p < 0.05); mean INL: 48.5 ± 5.04 and 38.5 ± 5.6 μm (p < 0.05)) in the course.

Conclusion: SD-OCT allows for classification, characterization, and further understanding of AMN lesions. Up to now, this is one of the largest AMN case series differentiating into different subtypes and following up for up to 5 years. Furthermore, we describe a new AMN subtype characterized by initially clinically visible yellowish parafoveal lesions, subtle pigmentary changes at late stage, lack of classic dark appearance on IR reflectance, involvement of RPE/Bruch's complex, and disruption of ellipsoid zone and interdigitation zone. The patients suffered from a prolonged visual impairment and paracentral scotomata. We propose the term AMN type 3 or "paracentral acute outer maculopathy."
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s10792-017-0742-9DOI Listing
December 2018

Mutation Spectrum of the ABCA4 Gene in 335 Stargardt Disease Patients From a Multicenter German Cohort-Impact of Selected Deep Intronic Variants and Common SNPs.

Invest Ophthalmol Vis Sci 2017 01;58(1):394-403

Institute of Human Genetics, University of Regensburg, Regensburg, Germany.

Purpose: Stargardt disease (STGD1) is an autosomal recessive retinopathy, caused by mutations in the retina-specific ATP-binding cassette transporter (ABCA4) gene. To establish the mutational spectrum and to assess effects of selected deep intronic and common genetic variants on disease, we performed a comprehensive sequence analysis in a large cohort of German STGD1 patients.

Methods: DNA samples of 335 STGD1 patients were analyzed for ABCA4 mutations in its 50 coding exons and adjacent intronic sequences by resequencing array technology or next generation sequencing (NGS). Parts of intron 30 and 36 were screened by Sanger chain-terminating dideoxynucleotide sequencing. An in vitro splicing assay was used to test selected variants for their splicing behavior. By logistic regression analysis we assessed the association of common ABCA4 alleles while a multivariate logistic regression model calculated a genetic risk score (GRS).

Results: Our analysis identified 148 pathogenic or likely pathogenic mutations, of which 48 constitute so far unpublished ABCA4-associated disease alleles. Four rare deep intronic variants were found once in 472 alleles analyzed. In addition, we identified six risk-modulating common variants. Genetic risk score estimates suggest that defined common ABCA4 variants influence disease risk in carriers of a single pathogenic ABCA4 allele.

Conclusions: Our study adds to the mutational spectrum of the ABCA4 gene. Moreover, in our cohort, deep intronic variants in intron 30 and 36 likely play no or only a minor role in disease pathology. Of note, our findings demonstrate a possible modifying effect of common sequence variants on ABCA4-associated disease.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1167/iovs.16-19936DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5270621PMC
January 2017

Primary skeletal muscle cells cultured on gelatin bead microcarriers develop structural and biochemical features characteristic of adult skeletal muscle.

Cell Biol Int 2016 Apr 20;40(4):364-74. Epub 2016 Jan 20.

Department of Physiology, Vegetative Physiology 4220, Hannover Medical School, 30625, Hannover, Germany.

A primary skeletal muscle cell culture, in which myoblasts derived from newborn rabbit hindlimb muscles grow on gelatin bead microcarriers in suspension and differentiate into myotubes, has been established previously. In the course of differentiation and beginning spontaneous contractions, these multinucleated myotubes do not detach from their support. Here, we describe the development of the primary myotubes with respect to their ultrastructural differentiation. Scanning electron microscopy reveals that myotubes not only grow around the surface of one carrier bead but also attach themselves to neighboring carriers, forming bridges between carriers. Transmission electron microscopy demonstrates highly ordered myofibrils, T-tubules, and sarcoplasmic reticulum. The functionality of the contractile apparatus is evidenced by contractile activity that occurs spontaneously or can be elicited by electrostimulation. Creatine kinase activity increases steadily until day 20 of culture. Regarding the expression of isoforms of myosin heavy chains (MHC), we could demonstrate that from day 16 on, no non-adult MHC isoform mRNAs are present. Instead, on day 28 the myotubes express predominantly adult fast MHCIId/x mRNA and protein. This MHC pattern resembles that of fast muscles of adult rabbits. In contrast, primary myotubes grown on matrigel-covered culture dishes express substantial amounts of non-adult MHC protein even on day 21. To conclude, primary myotubes grown on microcarriers in their later stages exhibit many features of adult skeletal muscle and characteristics of fast type II fibers. Thus, the culture represents an excellent model of adult fast skeletal muscle, for example, when investigating molecular mechanisms of fast-to-slow fiber-type transformation.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1002/cbin.10565DOI Listing
April 2016

Functional and structural brain modifications induced by oculomotor training in patients with age-related macular degeneration.

Front Psychol 2013 17;4:428. Epub 2013 Jul 17.

Institute for Experimental Psychology, University of Regensburg Regensburg, Germany.

Patients with age-related macular degeneration (AMD) are reliant on their peripheral visual field. Oculomotor training can help them to find the best area on intact peripheral retina and to efficiently stabilize eccentric fixation. In this study, nine patients with AMD were trained over a period of 6 months using oculomotor training protocols to improve fixation stability. They were followed over an additional period of 6 months, where they completed an auditory memory training as a sham training. In this cross-over design five patients started with the sham training and four with the oculomotor training. Seven healthy age-matched subjects, who did not take part in any training procedure, served as controls. During the 6 months of training the AMD subjects and the control group took part in three functional and structural magnetic resonance imaging (MRI) sessions to assess training-related changes in the brain function and structure. The sham-training phase was accompanied by two more fMRI measurements, resulting in five MRI sessions at intervals of 3 months for all participants. Despite substantial variability in the training effects, on average, AMD patients benefited from the training measurements as indexed by significant improvements in their fixation stability, visual acuity, and reading speed. The patients showed a significant positive correlation between brain activation changes and improvements in fixation stability in the visual cortex during training. These correlations were less pronounced on the long-term after training had ceased. We also found a significant increase in gray and white matter in the posterior cerebellum after training in the patient group. Our results show that functional and structural brain changes can be associated, at least on the short-term, with benefits of oculomotor and/or reading training in patients with central scotomata resulting from AMD.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3389/fpsyg.2013.00428DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3713239PMC
July 2013

Visual and morphological outcomes of bevacizumab (Avastin®) versus ranibizumab (Lucentis®) treatment for retinal angiomatous proliferation.

Int Ophthalmol 2012 Jun 18;32(3):259-68. Epub 2012 Apr 18.

Department of Ophthalmology, University Medical Center Regensburg, Regensburg, Germany.

Retinal angiomatous proliferation (RAP) is a variant of exudative age-related macular degeneration with particularly bad prognosis. The purpose of this work is to describe the long-term functional and morphological outcome of patients treated with intravitreal bevacizumab and ranibizumab. Retrospective case series of 16 eyes treated with bevacizumab and 19 eyes treated with ranibizumab. All patients received initially three intravitreal injections of bevacizumab (1.25 mg/0.05 ml) or ranibizumab (0.5 mg/0.05 ml) every 4 weeks. Follow-up ranged from 1 to 7 months after the third injection. Complete ophthalmologic examination including best-corrected visual acuity (VA), optical coherence tomography, fluorescein angiography, and in selected cases, indocyanine green angiography was performed. Triple intravitreal injections resulted in improvement of VA in bevacizumab-treated as well as in ranibizumab-treated patients; logarithm of the minimal angle of resolution (logMAR) 0.84 before treatment and 0.67 at month 9, and logMAR 0.75 before treatment and 0.59 at month 9, respectively. Central macular thickness (CMT) in the bevacizumab group improved from 363.67 ± 47.4 μm at baseline to 328 ± 49.77 μm at month 6 (p = 0.03) and 301 ± 129.69 at month 9 (p = 0.35). CMT in the ranibizumab group improved from 545.62 ± 167.39 μm at baseline to 395.88 ± 169.37 μm at month 6 and 411.83 ± 212.41 μm at month 9 (p = 0.03, p = 0.05, respectively). Patients with RAP might benefit from both intravitreal bevacizumab and ranibizumab treatments with stabilization of VA over a longer period of time. Close follow-up should nevertheless be performed in this special subgroup because of the high recurrence rate.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s10792-012-9562-0DOI Listing
June 2012

Acute visual loss after preoperative embolization of an ethmoidal metastasis.

Int Ophthalmol 2012 Apr 16;32(2):165-9. Epub 2012 Feb 16.

Department of Ophthalmology, University Medical Center Regensburg, Regensburg, Germany.

An unintentional embolization of retinal arteries is rare and has been documented as a complication after embolization of arteries supplying head and neck tumors. However, occlusion of the central retinal artery with severe loss of vision has never been reported to be a complication from embolization of tumor-supplying ethmoidal branches of the ophthalmic artery. A 40 year-old male patient with a history of right nephrectomy for renal cell carcinoma underwent preoperative radiological embolization of an ethmoidal metastasis after having experienced a life-threatening sinus bleeding. Repeated probing of the ophthalmic artery with an endovascular microcatheter for particle embolization of the tumor-supplying arteries was performed under anticoagulation with heparin. Postoperatively, a standard ophthalmological examination including extended vascular evaluation by angiography was performed. After extended probing of the ophthalmic artery a marked reduction in its blood flow occurred. Despite post-interventional imaging showing persisting perfusion of the central retinal and ciliary arteries, the patient developed complete loss of vision on this side four days later. At this time fundoscopy and fluorescein angiography revealed a recanalized central artery occlusion, while indocyanin angiography showed infarctions of the choroid. Radiological intervention via the ophthalmic artery can result in complete loss of vision, even after limited and transient obstruction of the vessel.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s10792-012-9525-5DOI Listing
April 2012

Gray matter alterations in visual cortex of patients with loss of central vision due to hereditary retinal dystrophies.

Neuroimage 2011 Jun 23;56(3):1556-65. Epub 2011 Feb 23.

Institute of Psychology, University of Regensburg, Regensburg, Germany.

In patients with central visual field scotomata a large part of visual cortex is not adequately stimulated. Over time this lack of input could lead to a reduction of gray matter in the affected cortical areas. We used Voxel Based Morphometry to investigate structural brain changes in patients with central scotomata due to hereditary retinal dystrophies and compared their results to those of normal sighted subjects. Additionally we correlated clinical and demographic characteristics like duration of disease, scotoma size, visual acuity, fixation stability and reading speed to the amount of gray matter in whole brain analyses within the patient group. We found a decrease in gray matter around the lesion projection zone in visual cortex of patients in comparison to controls. Gray matter loss along the posterior and middle portions of the calcarine sulcus is also correlated with scotoma size, indicating that indeed the lack of functional input provokes the gray matter alterations. In whole brain regression analyses within the patient group we found an additional cluster in the right superior and middle frontal gyri, slightly anterior to the frontal eye fields, where gray matter correlated positively with fixation stability. This could be regarded as a consequence of oculomotor learning.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.neuroimage.2011.02.055DOI Listing
June 2011

Epi-laser in situ keratomileusis: comparative evaluation of epithelial separation with 3 microkeratomes.

J Cataract Refract Surg 2008 Oct;34(10):1761-6

Department of Ophthalmology, Regensburg University Medical Center, Regensburg, Germany.

Purpose: To evaluate the cleavage plane, corneal cytoarchitecture, and cell vitality of separated corneal epithelial sheets created with 3 commonly used microkeratomes.

Setting: Laboratories of the Regensburg University Medical Center, Regensburg, Germany.

Methods: Mechanical separation of the epithelial layer in 10 porcine eyes and 2 human eyes was performed with 3 different microkeratomes (Amadeus II, Zyoptix XP, Epivision). Five of 10 porcine corneas and the 2 human corneas treated with each microkeratome were processed for histology, electron microscopy, and immunohistochemistry. In 5 of 10 porcine corneas, the corneal epithelial sheets were separated from the globe and cell vitality was assessed with the trypan blue dye vitality test.

Results: A reproducible epithelial separation with a smooth surface was achieved in all eyes. The cleavage plane was located between the lamina lucida and the lamina densa. Damage to epithelial cells was mainly limited to the cut margins.

Conclusions: Mechanical separation of the epithelial sheet in epithelial laser in situ keratomileusis (epi-LASIK) was safe and reproducible with all evaluated microkeratomes. Immunohistochemistry and electron microscopy showed the cleavage plane in epi-LASIK was between the basal epithelium and the basement membrane at the level of the lamina lucida.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.jcrs.2008.06.028DOI Listing
October 2008

Tear film function and corneal sensation in the early postoperative period after LASEK for the correction of myopia.

Graefes Arch Clin Exp Ophthalmol 2005 Sep 15;243(9):911-6. Epub 2005 Apr 15.

University Eye Clinic, University of Regensburg, Franz-Josef-Strauss Allee 11, 93042 Regensburg, Germany.

Purpose: Subepithelial nerves and stromal nerves of the cornea are damaged during LASEK surgery for the correction of myopia. This leads to a reduction in corneal sensation and to alterations of the tear film function in the early postoperative period. The aim of this study was to evaluate tear film function, corneal sensation and subjective symptoms of dry eye in the early postoperative period after LASEK for the correction of myopia.

Methods: LASEK surgery was performed in 20 eyes of 10 consecutive patients for the correction of myopia (-1.0 to -9.0 D, mean -4.86 D). Subjective symptoms of a dry eye were evaluated with a standardised questionnaire. Schirmer test with and without local anaesthesia, tear film break-up time, fluorescein staining of the cornea and corneal esthesiometry (Cochet-Bonnet) were performed before surgery and 1 week, 1 month, 2 months and 3 months after LASEK. Additionally corneal staining and subjective symptom severity scores were assessed 3 days after surgery.

Results: Corneal sensation was reduced 1 week after LASEK and recovered during the first month after LASEK. The tear film break-up time was reduced 1 week and 1 month after LASEK and reached preoperative values 2 months after surgery. Fluorescein staining was increased 3 days and 1 week after LASEK. Subjective symptom severity scores were increased 3 days, 1 week, 1 month and 2 months after LASEK. Schirmer tests values with local anaesthesia were significantly reduced at 3 months after surgery, but not at 3 days, 1 month, or 2 months. Schirmer test values without local anaesthesia were significantly decreased 2 and 3 months after LASEK, but not after 3 days and 1 month after LASEK.

Conclusions: LASEK alters ocular surface haemostasis and reduces corneal sensation in the early postoperative period. Subjective symptoms of dry eye were described during the first 2 months after surgery.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s00417-005-1130-0DOI Listing
September 2005
-->