bluuebunny/crossref_metadata_2025_split huggingface dataset:
Oxidative stress in retinal pigment epithelial cells: protective effect of wood‐derived phenolic compounds
Authors: REINISALO M , PAIMELA T , RYHäNEN T , KAUPPINEN A , KOSKELA A , SOININEN T , KAARNIRANTA K , KARJALAINEN RO 
Published: August 2012

AbstractPurpose Oxidative stress is related to chronic diseases including age‐related macular degeneration (AMD), which is the leading cause of blindness in the elderly worldwide. Functional roles of wood‐derived phenolic compounds such as flavonoids, phenolic acids, tannins and stilbenes are not well known, but some of them are effective antioxidants capable of providing defence against oxidative stress. Besides reducing ROS production by their antioxidant activity, phenolics can also activate the expression of phase II genes via the activation of transcription factors, such as Nfr2.Methods In this work, the protective effect of wood phenolics against oxidative stress were determined by pre‐incubating ARPE‐19 cells in medium containing wood compounds (pinosylvin, piceatannol, trans‐resveratrol or pinosylvin monomethyl ether) at different concentrations. After pre‐incubation with phenolics, cells were treated with oxidative stress causing agent, hydroquinone, for 24 hours. The viability of cells was determined by using MTT assay. To elucidate the mechanisms behind the phenolics‐mediated protection against oxidative stress and inflammation, the activity of genes such as Nrf2, IL‐6 and p62 was determined.Results Wood‐derived phenols were well tolerated by the cells and some of the compounds such as pinosylvin were able to increase the viability of cells in response to induced oxidative stress.Conclusion These results suggest that wood‐derived phenolic compounds can provide additional protection against oxidative stress in retinal cells.
Anatomy, physiology and pathophysiology of the meibomian gland
Authors: KNOP E , KNOP N , SULLIVAN DA 
Published: August 2012

AbstractPurpose The sebaceous meibomian glands (MG) in the eyelids, that secrete lipids for the superficial tear film layer, are of increased scientific and clinical interest. The recent MGD report of the non‐profit organization Tear Film and Ocular Surface Society (TFOS, www.tearfilm.org) revealed that MG Dysfunction (MGD) with lack of tear film lipids and the resultant evaporative type of dry eye is the main underlying reason for the wide‐spread dry eye disease that affects millions of patients world wideMethods A literature review based on the TFOS MGD Report together with own findings is discussed in order to explain the anatomy, physiology, pathophysiology and clinics of MGD.Results MGD is a multifactorial disease based on endogeneous and exogeneous factors that interact in self propagating vicious circles. Advancing age, female sex, environmental factors such as topical medication, bacterial influences and probably subclinical inflammatory pathways as well as contact lens wear are some main factors lead to the onset and propagation of MGD. These result in hyperkeratinization of the gland epithelium as well as increased viscosity of the secretum. Together this results in the obstructive type of MGD. Two effector arms of obstruction lead to a primary lack of oil on the tear film with downstream evaporative dry eye but also to a secondary hidden degeneration of the glandular tissue inside the lids that results in gland atrophy.Conclusion Obstructive MGD with downstream lipid deficiency is now recognized as the main cause for dry eye disease and this achievement of the TFOS MGD Workshop has already changed/revolutionized our view on dry eye disease as well as lead to several new developments for diagnosis and treatment that specifically address MGD. Support DFG KN 317‐11
Identification of MGD in dry eye patients and its treatment in the practical clinical setting & The Austrian perspective on MGD
Authors: HORWATH‐WINTER J , RABENSTEINER DF , BOLDIN I 
Published: August 2012

AbstractMGD can be found in about 70% of patients with ocular discomfort as evaluated in a large clinic‐based population of Austria. It is characterized by a continuum of clinical severity. Especially discrete cases are often underestimated und receive not enough attention. In patients with ocular discomfort it is important to investigate the blinking action, the lid margins (crusts, vascularisation, Marx line, meibomian orifices) and also to perform the expression of the meibomian glands. Tear deficiency is often accompanied with MGD therefore the function of the lacrimal glands should be tested. To evaluate the damage of the ocular surface, staining with fluorescein and lissamine green are recommended. Further important diagnostic measures are the evaluation of the lipid layer and the examination of the meibomian glands with meibography. Although there is an overlap between different subtypes of dry eye, proper diagnostic evaluation is important to identify adequate therapeutic treatments that would best target the underlying dysfunctions. The most commonly recommended treatment option for every stage of MGD remains eyelid hygiene that should be performed on a regular basis. Eyelid warming to melt the meibum and eyelid massage to express secretion shall prevent obstruction of the terminal ducts. To improve compliance special devices that are more convenient for the patients can be used. Instillation of artificial lubricants, especially with lipid containing components may stabilize the tear film. Essential fatty acids, topical and systemic antibiotics and other anti‐inflammatory medication are further important therapeutic options.
Characterization of human corneal grafts’ transparency by optical coherence tomography and scattering measurements
Authors: HOFFART L , CASADESSUS O , GEORGES G , SIOZADE L , DEUMIé C 
Published: August 2012

AbstractPurpose In clinical and graft sorting applications, cornea’s transparency is only subjectively qualified. The aim of this study is to bring tools to achieve transparency quantification regarding the evolution of edema within the tissue.Methods The samples are human corneal grafts rejected from bank of tissue due to physiologic issues, which are submitted to swelling protocol to study their properties with edema. A multiscale analysis of the microstructure imaged by 1 µm resolved Optical Coherence Tomography (OCT) combined with a detailed characterization of backscattering properties is performed. Electromagnetical modelization is used to numerically link scattering measurements with structural defects observed with OCT.Results Backscattered intensity measurements enable corneal grafts’ transparency evaluation (backscattering level increases with swelling). Moreover, microstructural tissue modifications occurring during swelling (microstructure disorganization and heterogeneities) are highlighted by OCT imagery. We show that the observed heterogeneities imply higher scattering levels and explain the experimental results.Conclusion Combining both techniques allows linking the scattering behavior with the evolution of microstructures within the tissue and permits to quantify corneal grafts transparency. This study has to be extended to tissues eligible for graft but this characterization in the backscattered space could directly be applied to future study of tissues before removal or to in vivo diagnosis.
In vitro studies on the mechanism of action of VEGF and its inhibitors on blood‐retina barrier
Authors: DEISSLER H , LANG G 
Published: August 2012

AbstractPurpose VEGF‐induced permeability of immortalized endothelial cells of the bovine retina (iBREC) can be completely restored by the VEGF‐binding Fab‐fragment ranibizumab, but expression of other growth factors like bFGF, IGF‐1 or PLGF is also elevated in diabetic macular edema (DME). Therefore, we investigated whether combination of these growth factors enhance or diminish the long‐term effect of VEGF and whether combined effects can be restored by VEGF‐inhibition alone. We also studied potential uptake and accumulation of ranibizumab or the humanized VEGF‐binding antibody bevacizumab.Methods Measured transendothelial resistance (TER) of iBREC (+/‐ growth factors or inhibitors) showed effects on permeability, indicated also by Western blot‐determined tight junction protein Claudin‐1. Uptake of VEGF inhibitors by iBREC was visualised by immunofluorescence staining and Western blot analyses.Results VEGF decreased TER and Claudin‐1 in a concentration dependent manner whereas bFGF, IGF‐1 or PLGF as single agent did not influence these processes during treatment for 2 days. In contrast to PLGF, bFGF and IGF‐1 maintained the effect of VEGF especially at low VEGF concentrations. Reduction of TER or Claudin‐1 induced by combination of all growth factors was completely restored by addition of ranibizumab. Both VEGF inhibitors were internalised but bevacizumab accumulated further. Ranibizumab was found in the membrane/organelle fraction, whereas bevacizumab associated with the cytoskeleton. Both inhibitors did not disturb the barrier of iBREC.Conclusion VEGF is mainly responsible for disrupting the barrier function of REC. This supports VEGF targeting as a therapeutic concept. Independent research grant by Novartis Pharma, Germany
Role of retinal glial cells in pathogenesis of macular oedema
Authors: YANDIEV Y , BRINGMANN A , WIEDEMANN P 
Published: August 2012

AbstractPurpose Macular edema is a complex nonspecific reaction that results in intraretinal fluid accumulation and leads to a decrease of retinal transparency and visual impairment. Virtually all retinal disorders associated with ischemia, inflammation and/or mechanical traction may be accompanied by the development of macular edema. The pathogenic mechanisms underlying the development of macular edema are largely unresolved. Most studies favor vasogenic edema as key mechanism in the development of macular edema. However there are indications that a swelling of retinal Müller cells may also contribute to the development of macular edema.Methods Immunohistochemical staining as well as recording of Müller cells behavior was investigated under normal conditions, under osmotic stress and under different pathological processes, e.g., retinal ischemia, ocular inflammation, and diabetes.Results The Müller cells are responsible for the maintenance of the retinal homeostasis including intraretinal osmolyte and water homeostasis through coupling of transglial water fluxes (via aquaporins) to potassium currents clearance. Functional alterations of Müller cells in course of ischemia and/or inflammation contribute to the downregulation of potassium conductance and intracellular overload of potassium ions. This results in osmotically driven water movements from the blood and vitreous into the glial cells and causes neuronal hyperexcitability and glial cellConclusion An impairment of ion and water movements through Müller cells (in addition to vascular leakage) may contribute to the development of macular edema. A better understanding of the mechanisms of cellular ion and water homeostasis will facilitate the development of efficient edema‐resolving drugs.
Combination of ranibizumab and laser photocoagulation in CRVO
Authors: WIEDEMANN P , REHAK M 
Published: August 2012

AbstractPurpose In a model of CRVO upregulation of VEGF was strongest in the ischemic areas. Therefore initiated a proof of concept study to evaluate the efficacy of intraocular ranibizumab injections combined with laser photocoagulation of the non perfused areas in patients with CRVO.Methods 22 patients with areas of non‐perfusion were randomized into two groups. In the treatment arm patients received the ranibizumab injections with additional selective laser photocoagulation. The controls were treated with ranibizumab only. All patients received an upload and were re‐injected in a PRN regimen. The results at month 6 were evaluated. The change in BCVA compared with baseline as well as the amount of ranibizumab injections and the percentage of patients progressing to neovascularization ( retina and/or anterior segment) were analyzed in the both arms.Results BCVA increased at month 6 compared with baseline in the treatment arm from 61.6±12.7 to 68.9±13.7 ETDRS letters and in the control arm from 59.25±10.9 to 64.1±16.5 letters. One control patient developed retinal neovascularisation and required panretinal aser photocoagulation. Due to the small number of patients the differences between experimental and control arm are not statistically significant. The sample size calculation showed, that 100 patients are required to achieve the statistical power of 90%.Conclusion The preliminary results of the study showed a positive effect of the additional selective laser photocoagulation in patients with CRVO. The laser treatment seems to lead to faster and substantial resolution of the macular edema. A multicenter trial is currently prepared to confirm the results of this proof of concept study.
Vasomotor reaction of retinal arterioles in hypoxic and ischemic conditions
Authors: POURNARAS CJ 
Published: August 2012

AbstractPurpose Retinal blood flow is autoregulated by the adaptation of the vascular tone of resistance vessels (arterioles, capillaries) to changes in the perfusion pressure (PP) or metabolic needs of the tissue. The purpose of this study was to evaluate the disturbance of arteriolar reactivity, and thus of blood flow regulation, during the evolution of ischemic retinal microangiopathies.Methods Much of our basic knowledge of retinal arteriolar reactivity is based on data obtained from animal experiments through the use of invasive techniques. However, a variety of non‐invasive techniques has been applied to the human eye for the investigation of retinal hemo‐dynamics and, more specifically, the reactivity of the retinal arterioles in response to a number of physiologic and pharmacologic stimuli, under normal, hypoxic and ischemic conditions.Results In patients with non‐proliferative diabetic retinopathy (DR), isocapnic hypoxia induces a significant increase in Vleuk in the perifoveal circulation, whereas in patients with proliferative DR, the diameter of the retinal vessels remains unchanged, indicating that blood flow regulation in response to a hypoxic challenge is blunted,consequent to the hypoxic retinal conditions. In those patients a hyperoxia‐induced blunted vasoconstriction of the retinal arterioles is also observed. The ability of the retinal arterioles to respond to changes in ocular PP is altered in diabetes, while the response of retinal vessels to diffuse luminance flicker is blunted, particularly in patients suffering from insulin‐dependent diabetes.Conclusion During the evolution of retinal ischemic microangiopathies, impairment of various mechanisms of retinal arteriolar reactivity leads to disturbed retinal blood flow regulation.
Anatomical location of polypoidal choroidal vasculopathy lesions inferred from simultaneous ICGA‐OCT
Authors: KANG SW , JH KIM , HA HS 
Published: August 2012

AbstractPurpose To identify the spatial location of polypoidal choroidal vasculopathy (PCV) lesions including branching vascular network (BVN) and late geographic hyperfluorescence (LGH).Methods This retrospective study involved 15 eyes (15 subjects) affected by active PCV. Utilizing innate software for simultaneous indocyanine green angiography (ICGA) and optical coherence tomography (OCT), we identified the corresponding tomographic locations of BVN and LGH on ICGA.Results LGH was noted in 9 eyes, and the extent of LGH was the same (5 eyes) as or larger (4 eyes) than the extent of BVN. The extent of ‘double layer sign’ on OCT coincided exactly with the extent of LGH on ICGA. Image analysis revealed that larger vessels of BVN located not in‐between retinal pigment epithelium and Bruch’s membrane but within choroidal layer.Conclusion This study indicates that, at least, a part of BVN locates within choroidal layer. And the tomographic location of the lesion corresponding to LGH lies above Bruch’s membrane. The origin of LGH would be fluorescein staining of the lesion above Bruch’ membrane, possibly due to exudation from BVN.
Long‐term results of deep anterior lamellar keratoplasty in patients with keratoconus
Authors: FOURNIE P , TOUBOUL D , ARNE JL , COLIN J , MALECAZE F 
Published: August 2012

AbstractPurpose Long‐term endothelial cell density changes and visual and refractive outcomes after descemetic (d) and predescemetic (pd) deep anterior lamellar keratoplasty (DALK) using the big‐bubble technique in eyes with keratoconus.Methods Retrospective, consecutive, non‐comparative, case series analysis of 95 eyes that have undergone DALK for keratoconus using the big‐bubble technique with at least 1 year of follow‐up. Big‐bubble was achieved in 74 (77.9%) eyes (dDALK), whereas 21 (22.1%) eyes underwent manual lamellar dissection (pdDALK) because of failed big‐bubble.Results Descemet ruptures occurred in 13 of 95 cases (13.7%). Five ruptures (5.3%) were converted to penetrating keratoplasty. Mean length of follow‐up was 5.3 years (range, 1‐8 years). Postoperative best spectacle‐corrected visual acuity was significantly better in dDALK group than in pdDALK group at years 1 and 2. But, at the final examinations, there was no significant difference between the study groups (0.25 ± 0.22 logarithm of the minimum angle of resolution in dDALK group and 0.33 ± 0.15 logarithm of the minimum angle of resolution in pdDALK group; p = 0.12). The 2 groups were comparable regarding astigmatism and spherical equivalent refractive error throughout the follow‐up period. Mean endothelial cell loss was 22.5 ± 17.9% at last follow‐up with most of the loss occurring in the first year (8.7% ± 5.6%). Stromal graft rejection episodes occurred in 3 eyes (3.2%), which resolved with appropriate therapy.Conclusion DALK using the big‐bubble technique is effective in patients with keratoconus. In DALK, manual lamellar dissection is a reasonable alternative when big‐bubble separation of the Descemet membrane is not achieved.
Visual and refractive outcomes of intracorneal ring segments in the treatment of keratoconus: the RETICS multicentrical study
Authors: VEGA‐ESTRADA A , ALIO JL , MICHAEL R , BARRAQUER RI 
Published: August 2012

AbstractPurpose Analyze the outcomes of intracorneal ring segment (ICRS) implantation for the treatment of Keratoconus based on preoperative visual impairment. Design: Multicenter, retrospective, nonrandomized study.Methods 611 eyes of 361 keratoconic patients were evaluated. Subjects were classified according to their preoperative corrected distance visual acuity (CDVA) into five different groups: Grade I, CDVA of 0.90 or better, Grade II, CDVA equal or better than 0.60 and worse than 0.90, Grade III, CDVA equal or better than 0.40 and worse than 0.60, Grade IV CDVA equal or better than 0.20 and worse than 0.40 and Grade Plus, CDVA worse than 0.20. Success and failure indexes were defined based on visual, refractive, corneal topographic and aberrometric data and evaluated in each group six months after ICRS implantation.Results Significant improvement after the procedure was observed regarding uncorrected distance visual acuity in all grades (p<0.05). CDVA significantly decrease in Grade I (p<0.01), but significantly increases in all other grades (p<0.05). 37.9% of patients with preoperative CDVA 0.6 or better gained 1 or more lines of CDVA, while 82.8% of patients with preoperative CDVA 0.4 or worse gained 1 or more lines of CDVA (p<0.01). Spherical equivalent and keratometry readings showed a significant reduction in all Grades (p≤0.02). Corneal higher order aberrations did not change after the procedure (p≥0.05).Conclusion Based on preoperative visual impairment, ICRS implantation provides significantly better results in patients with a severe form of the disease. A notably lost of CDVA lines can be expected in patients with a milder form of Keratoconus.
Keratocyte density after microkeratome LASIK versus femtosecond laser‐assisted LASIK
Authors: CANADAS SUAREZ PILAR , HERNANDEZ‐VERDEJO JL , DE BENITO LLOPIS L , DRAKE P , TEUS MA 
Published: August 2012

AbstractPurpose to compare the keratocyte density after microkeratome LASIK (MK‐LASIK) and femtosecond‐laser assisted LASIK (FS‐LASIK)Methods We performed a prospective study of myopic patients that underwent MK‐LASIK or FS‐LASIK. We measured keratocyte density 3 and 15 months, and 3‐5 years after the surgery using confocal microscopyResults we included 31 eyes in LASIK (FS‐LASIK) and 30 eyes MK‐LASIK, we detected an initial increase in the keratocyte population of the whole cornea, due to an increase in the stromal bed and mid and posterior stromal layers, followed by a normalisation of those deeper layers, and a decrease of the cell density in the stromal flap and stromal bed 3‐5 years postoperatively. The average cell density throughout the cornea was not decreased compared to controls.Conclusion : we found a reorganization of keratocytes in the cornea up to 5 years after LASIK, with a decrease in the stromal flap and bed, but maintaining normal average cell densities, and with no significant differences between MK and FS‐LASIK.
Evaluation of intraocular pressure according to corneal thickness before and after Excimer laser corneal ablation for myopia
Authors: HAMED AZZAM S , BRISCOE D , TOMKINS O , SHEHADEH M , GARZOZI H 
Published: August 2012

AbstractPurpose Intraocular pressure is affected by corneal thickness and biomechanics. Following ablative corneal refractive surgery, corneal structural changes occur. Our aim in this study was to determine the relation between the mean central corneal thickness and the change in intraocular pressure measurements following various corneal ablation techniques, using different measurement methods.Methods This is a prospective, nonrandomized study.200 myopic eyes undergoing laser in situ keratomileusis or photorefractive keratectomy were enrolled. Corneal parameters examined included, full ocular examination, measurement of central corneal thickness, corneal topography, corneal curvature and ocular refractivity. Intraocular pressure measurements were obtained using three different instruments: Non Contact Tonometer, Goldmann Applanation Tonometer and TonoPen XL (TonoPen‐Central, and TonoPen‐Peripheral). All measurements were performed preoperatively and 4 months postoperatively. differences in inter‐device intraocular pressure measurements were done using ANOVA test.Results Postoperative intraocular pressure was significantly lower than preoperative values, with all instruments (p value <0.001, Student's t‐test). The postoperative intraocular pressure decrease was smallest using the Tonopen‐XL compared to the Goldmann applanation tonometer and Non‐contact tonometer (p value <0.001,ANOVA).Conclusion Intraocular pressure readings are significantly reduced following corneal ablation surgery. We determined in our myopic patient cohort that the TonoPen XL intraocular pressure measurement method is the least affected following photorefractive keratectomy and laser in situ keratomileusis as compared to other techniques.