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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
31

Méthodes de traitement d’images pour le dépistage de la rétinopathie diabétique assisté par ordinateur / Image processing methods for computer-aided screening of diabetic retinopathy

Zhang, Xiwei 04 July 2014 (has links)
La rétinopathie diabétique est la cause principale de cécité dans la population en âge de travailler. Une détection précoce et un traitement adapté permettent de réduire considérablement le risque de perte de vue. Les autorités médicales recommandent un examen annuel pour les patients diabétiques. Plusieurs programmes de dépistage de la rétinopathie diabétique ont été déployés pour appliquer cette recommandation. L'objectif du projet TeleOphta était de détecter automatiquement des examens normaux dans un système de dépistage du diabète, afin de réduire le fardeau des lecteurs, et donc servir plus de patients. Cette thèse propose plusieurs méthodes pour extraire des informations liées à des lésions provoquées par la rétinopathie diabétique dans des images en couleurs du fond d'œil.La détection des exsudats, microanévrismes et hémorragies est discutée en détail. L'un des principaux défis de ce travail est de traiter des images cliniques, acquises avec différents types de caméras de fond d'œil, par des personnes différentes. Par conséquent, l'hétérogénéité de la base de données est élevé. Des nouvelles méthodes de pré-traitement, qui effectuent non seulement des tâches de normalisation et de débruitage, mais aussi de détection de réflexions et d'artefacts optiques, sont proposées. Des méthodes de segmentation des candidats basées sur la morphologie mathématique, et de nouveaux descripteurs de texture et de contexte sont proposées pour la caractérisation des lésions. Un algorithme de forêts aléatoires est utilisé pour choisir les lésions parmi les candidats. Les méthodes proposées utilisent largement des nouvelles méthodes d'analyse des résidus.En outre, trois nouvelles bases de données publiques d'images de la rétine, e-ophtha EX, e-ophtha MA et e-ophtha HM, respectivement conçues pour développer et évaluer les méthodes de détection d' exsudats,de microanévrismes et d'hémorragies, sont proposées dans ce travail. Les images ont été extraites du réseau de télémédecine OPHDIAT pour le dépistage de la rétinopathie diabétique. Des annotations manuelles détaillées des lésions sont fournies avec ces bases de données. Les algorithmes proposés sont évalués sur ces bases.Les méthodes proposées ont été intégrées dans le système TeleOphta , qui est présentée et évaluée sur deux grandes bases de données. Chaque dossier du patient est classé en deux catégories: “Pour avis” ou “Normal". La classification est basée non seulement sur les résultats des méthodes présentées, mais aussi sur les signatures d'image fournies par d'autres partenaires, ainsi que sur l'information médicale du patient, et les données liées à l'acquisition. L'évaluation montre que le système TeleOphta permet de traiter deux fois plus de patients dans un réseau de dépistage, à moyens constants. / Diabetic retinopathy is the main cause of blindness among the middle-aged population. An early detection and adapted treatment considerably reduce the risk of sight loss. Medical authorities recommend an annual examination to diabetic patients. Several diabetic retinopathy screening programs have been deployed to enforce this recommendation. The aim of the TeleOphta project was to automatically detect normal examinations in a diabetic screening system, in order to reduce the burden on readers, and therefore serve more patients. This thesis proposes several methods to extract information linked to diabetic retinopathy lesions from color eye fundus images.The detection of exudates, microaneurysms and hemorrhages is discussed in detail. One of the main challenges of this work is to deal with clinical images, acquired by different types of eye fundus cameras, by different persons. Therefore the data base heterogeneity is high. New pre-processing methods, which perform not only normalization and denoising tasks, but also detect reflections and artifacts in the images, are proposed. Novel candidate segmentation methods based on mathematical morphology, and new textural and contextual features for lesion characterization, are proposed. A random forest algorithm is used to detect lesions among the candidates. The proposed methods make extensive use of new residue analysis methods.Moreover, three new publicly available retinal image databases, e-ophtha EX, e-ophtha MA and e-ophtha HM, respectively designed to develop and evaluate exudate, microaneurysms and hemorrhages detections methods, are proposed in this work. The images are extracted from the OPHDIAT telemedicine network for diabetic retinopathy screening. Manual annotations of the lesions are given in detail in these databases. The proposed algorithms are evaluated on these databases.The proposed methods have been integrated within the TeleOphta system, which is presented and evaluated on two large databases. Each patient record is classified into two categories: “To be referred” or “Normal”. The classification is based not only on the results of the presented methods, but also on image signatures provided by other partners, as well as on medical and acquisition-related information. The evaluation shows that the TeleOphta system can make about 2 times more patients benefit from the diagnosis service.
32

Segmentace významných objektů v barevných oftalmologických obrazech / Segmentation in the color fundus imges

Malínský, Miloš January 2008 (has links)
Optic nerve head and macula are important structures in fundus images. Detection and measurement plays crucial role in several diagnosis methods of optic disease. This work is focused on the detection of the central point of macula and optic nerve head, where the inner border is detected too. There are many methods for extracting this structure in retinal images. Due to the unique properties of each acquisition technique, a single generally acknowledged detection algorithm does not exist. The whole detection process is described from preprocessing through segmentation towards postprocessing. Presented methods are based on the combination of correlation techniques, Hough transform, active contours and morphological operations. The detected contours of the optic nerve head are evaluated and quantitatively compared with the contour drawn by experienced ophthalmologist. The master thesis contains quantity of images that help to describe detection methods.
33

Mögliche Korrelation zwischen dem Stadium der altersabhängigen Makuladegeneration und der zentralen Hornhautdicke

Koch, Christian 08 October 2015 (has links)
Deutschsprachige Zusammenfassung Dissertation zur Erlangung des akademischen Grades Dr. med. Titel: Mögliche Korrelation zwischen dem Stadium der altersabhängigen Makuladegeneration und der zentralen Hornhautdicke eingereicht von: Christian Koch angefertigt an der: Klinik und Poliklinik für Augenheilkunde Universität Leipzig betreut von: Professor Dr. med. Peter Wiedemann Klinik und Poliklinik für Augenheilkunde Universität Leipzig Monat und Jahr: Juni 2015 Annahme: Es soll ein statistischer Zusammenhang zwischen der zentralen Hornhautdicke in der Pupillenmitte mit dem nicht exsudativen frühen Stadium der AMD, dem exsudativen späten Stadium der AMD und einer Kontrollgruppe überprüft werden. Methodik: Die erste Studiengruppe stellten 48 Augen von 48 Patienten mit einer Form der frühen AMD dar (Durchschnittsalter 75,4 Jahre, 70,8% der Probanden waren Frauen). Die zweite Studiengruppe bildeten 49 Augen von 49 Patienten mit einer Form der späten AMD (Durchschnittsalter 79,8 Jahre, 59,2% der Probanden waren Frauen). Als Kontrollgruppe wurden 49 Augen von 49 Individuen ohne retinale oder korneale Erkrankungen genutzt (Durchschnittsalter 68,9 Jahre, 59,2% der Probanden waren Frauen). Die Vermessung der Hornhautdicke in Pupillenmitte im Sinne der Hornhautmittendicke erfolgte als Pachymetrie mit der Oculus Pentacam. Ergebnisse: Die durchschnittliche zentrale Hornhautdicke betrug bei der Kontrollgruppe 552,76 μm (SD 36,27 μm), bei der nicht exsudativen Gruppe 552,19 μm (SD 31,27 μm) und bei der exsudativen Gruppe 553,73 μm (SD 33,11 μm). Die Extrempunkte der Kontrollgruppe lagen bei 483 und 640 μm, der Gruppe der nicht exsudativen AMD bei 480 und 617 μm und Minimum und Maximum der exsudativen Gruppe bei 473 und 617 μm. Es gab keine statistisch signifikanten Unterschiede im arithmetischen Mittel der zentralen Hornhautdicke in Pupillenmitte bei der Studiengruppe mit früher AMD im Vergleich mit der Studiengruppe mit später AMD und jeweils im Vergleich zur Kontrollgruppe (P > 0,05). Schlussfolgerung: Die Messwerte der zentralen Hornhautdicke bei Patienten mit früher AMD, später AMD und Kontrollindividuen unterscheiden sich nicht. Die Erhebung der Hornhautmittendicke bietet somit keine Screeningmöglichkeit zur Erkennung einer AMD. / English Abstract Central corneal thickness in patients with AMD Koch, C.; Jochmann, C.; Wiedemann, P. University of Leipzig, Department of Ophthalmology and Eye Hospital, Leipzig, Germany Purpose: To evaluate central corneal thickness in patients with AMD in the early and late phase and a control group. Method: The first study group was made up of 48 eyes of 48 patients with early AMD (mean age 75.4 years, 70.8 % women), the second study group was made up of 49 eyes of 49 patients with late AMD (mean age 79.8 years, 59.2 % women). 49 eyes of 49 individuals without any retinal or corneal damage (mean age 68.9 years, 59.2 % women) were used as control group. The central corneal thickness was measured with the Oculus Pentacam pachymetry. Results: The mean central corneal thickness in early non-exudative AMD group was found to be 552.19 μm (SD 31.27 μm), while the mean central corneal thickness in the late exudative AMD group was measured as 553.73 μm (SD 33.11 μm). The control group had a mean central corneal thickness of 552.76 μm (SD 36.27 μm). There were no statistically significant differences in the mean central corneal thickness in the early non-exudative AMD group in comparison with the late exudative AMD group and each of them compared to the control group (P > 0,05). Conclusion: The central corneal thickness measurements do not differ in patients with early non-exudative AMD, late exudative AMD and control subjects.
34

Automated methods in the diagnosing of retinal images

Jönsson, Marthina January 2012 (has links)
This report contains a summation of a variety of articles that have been read and analysed. Each article describes different methods that can be used to detect lesions, optic disks, drusen and exudates in retinal images. I.e. diagnose e.g. Diabetic Retinopathy and Age-Related Macular Degeneration. A general approach is presented, which all methods more or less is based on. Methods to locate the optic disk The PCA  kNN Regression Hough Transform Fuzzy Convergence Vessel Direction Matched Filter Etc. The best method based on result, reliability, number of images and publisher is kNN regression. The result of this method is remarkably good and that brings some doubt about its reliability. Though the method was published at IEEE and that gives the method a more trustful look. A next best method which also is very useful is Vessel Direction Matched Filter. Methods to detect drusen – diagnose Age-Related Macular Degeneration PNN classifier Histogram approach Etc. The best method based on result, reliability, number of images and publisher is the PNN classifier. The method had a sensitivity of 94 % and a specificity of 95 %. 300 images were used in the experiment which was published by the IEEE in 2011. Methods to detect exudates – diagnose Diabetic Retinopathy Morphological techniques Luv colour space, Wiener filter an Canny edge detector. The best method based on result, reliability, number of images and publisher is an experiment called “Feature Extraction”. The method includes the Luv colour space, Wiener filter (remove noise) and the Canny edge detector. / Den här rapporten innehåller en sammanfattning av ett flertal artiklar som har blivit studerade. Varje artikel har beskrivit en metod som kan användas för att upptäcka sjuka förändringar i ögonbottenbilder, det vill säga, åldersförändringar i gula fläcken och diabetisk retinopati. Metoder för att lokalisera blinda fläcken PCA kNN regression Hough omvandling Suddig konvergens Filtrering beroende på kärlens riktning Mm. Den bästa metoden baserat på resultat, pålitlighet, antal bilder och utgivare är kNN regression. De förvånansvärt goda resultaten kan inbringa lite tvivel på huruvida resultaten stämmer. Artikeln publicerades dock av IEEE och det gör artikeln mer trovärdig. Den näst bästa metoden är filtrering beroende på kärlens riktning. Metoder för att diagnosticera åldersförändringar i gula fläcken PNN klassificeraren Histogram Mm. Den bästa metoden baserat på resultat, pålitlighet, antal bilder och utgivare är PNN klassificeraren. Metoden hade en sensitivitet på 94 % och en specificitet på 95 %. 300 bilder användes i experimentet som publicerades av IEEE år 2011. Metoder att diagnosticera diabetisk retinopati Morfologiska tekniker Luv colour space, Wiener filter and Canny edge detector. Den bästa metoden baserat på resultat, pålitlighet, antal bilder och utgivare är ett experimentet som heter ”Feature Extraction”. Experimentet inkluderar Luv colour space, Wiener filter (brus borttagning) och Canny edge detector
35

Three-Dimensional Tomographic Features of Dome-Shaped Macula by Swept-Source Optical Coherence Tomography / スウェプトソース光干渉断層計によるドーム型黄斑の3次元構造解析

ABDALLAH, A. ELLABBAN 23 March 2015 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(医学) / 甲第18855号 / 医博第3966号 / 新制||医||1007(附属図書館) / 31806 / 京都大学大学院医学研究科医学専攻 / (主査)教授 河野 憲二, 教授 黒田 知宏, 教授 富樫 かおり / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM
36

Značaj optičke koherentne tomografije makule kod glaukoma otvorenog ugla / Optical coherence tomography of macula in primary open angle glaucoma

Babović Siniša 13 May 2016 (has links)
<p>Cilj ovog istraživanja je bio da se utvrdi da li postoji razlika u debljini makule kod pacijenata sa glaukomom otvorenog ugla (POAG) u odnosu na zdravu populaciju i u zavisnosti od stepena progresije bolesti, kao i da se utvrdi da li postoji povezanost između promene debljine makule i stepena o&scaron;tećenja vidnog polja i debljine peripapilarnog sloja nervnih vlakana u zavisnosti od stepena progresije bolesti. Materijal i metode: U ovu kliničku prospektivnu studiju je uključeno 186 pacijenata. Na osnovu kliničkog nalaza formirane su tri grupe. Prva grupa (kontrolna &ndash; grupa zdravih): 68 pacijenata bez očnih oboljenja, sa najboljom korigovanom vidnom o&scaron;trinom &ge; 0.9, intraokularnim pritiskom (IOP) &le; 21 mmHg, normalnim odnosom ekskavacije i povr&scaron;ine glave vidnog živca i normalnim nalazom vidnog polja. Druga grupa (rani glaukom): 78 pacijenata sa klinički dijagnostikovanim primarnim glaukomom otvorenog ugla (sa karakterističnim o&scaron;tećenjem glave vidnog živca i sloja nervnih vlakana retine i kod kojih je srednja vrednost devijacije standardne automatske perimetrije MD &gt; -6 dB, prema Hodap klasifikaciji), bez drugih očnih ili sistemskih oboljenja, koja bi imala uticaj na nastanak glaukoma i sa najboljom korigovanom vidnom o&scaron;trinom &ge; 0.5. Treća grupa (glaukom srednjeg stepena): 40 pacijenata sa klinički dijagnostikovanim primarnim glaukomom otvorenog ugla (sa karakterističnim o&scaron;tećenjem glave vidnog živca i sloja nervnih vlakana retine i kod kojih je srednja vrednost devijacije standardne automatske perimetrije -6 dB &gt; MD &gt; -12 dB, prema Hodap klasifikaciji), bez drugih očnih ili sistemskih oboljenja, koja bi imala uticaj na nastanak glaukoma i sa najboljom korigovanom vidnom o&scaron;trinom &ge; 0.5. Svim pacijentima je bio urađen kompletan oftalmolo&scaron;ki pregled, kompjuterizovano vidno polje (Humphrey Field Analyzer, Carl Zeiss Meditec, Jena, Germany, SITA Standard, test C 24-2) i optička koherentna tomografija sloja nervnih vlakana peripapilarno i u predelu makule (SOCT Copernicus HR, Optopol Tech. SA, Zawiercie, Poland). Rezultati: Perifovea i parafovea, pokazuju statistički značajno smanjenje debljine i zapremine sloja nervnih vlakana u odnosu na stepen progresije glaukoma otvorenog ugla, pri čemu je ono nagla&scaron;enije u perifovei (p&lt;0,05). U svim segmentima makule (TPeriF, IPeriF, SPeriF, NPeriF, TParaF, SParaF, IParaF i NParaF) dolazi do smanjenja debljine i zapremine sloja nervnih vlakana sa progresijom bolesti (p&lt;0,05). Segmenti makule TPeriF, IPeriF, a potom i SPeriF, prema navedenom redosledu, predstavljaju segmente sa najvećim potencijalom za predikciju ranih glaukomskih o&scaron;tećenja s obzirom na uočeno najveće smanjenje debljine i zapremine nervnih vlakana (p&lt;0,05). Segmenti makule SParaF i NParaF predstavljaju segmente sa najvećim potencijalom za predikciju napredovanja glaukomskih o&scaron;tećenja srednjeg stepena s obzirom na uočeno najveće smanjenje debljine i zapremine nervnih vlakana (p&lt;0,05). Debljina RNFL glave vidnog živca se statistički značajno smanjuje sa progresijom bolesti u svim posmatranim segmentima (p&lt;0,05). Međusobni odnos između grupe zdravih i grupe pacijenata sa ranim glaukomom ukazuje da je statistički značajno smanjenje debljine RNFL prisutno u svim segmentima osim u segmentima P3 i P4 (p&gt;0,05). Merenja debljine RNFL u segmentu P6 imaju najbolji potencijal za predikciju ranog glaukoma s obzirom na najizraženije smanjenje debljine nervnih vlakana upravo u ovom segmentu (p&lt;0,05). Merenja debljine RNFL u segmentu P1 ima najbolji potencijal za predikciju dalje progresije bolesti. Debljina sloja nervnih vlakana makule srazmerna je smanjenju debljine RNFL na glavi vidnog živca, pri čemu je ona uočljivija na nivou segmenata koji su okarakterisani kao dobri prediktori za nastanak, odnosno progresiju bolesti (P6 sa IPeriF i TPeriF, odnosno P1 sa SPeriF), &scaron;to dodatno nagla&scaron;ava njihovu važnost u dijagnostici glaukoma otvorenog ugla. Debljina makule kod pacijenata sa glaukomom otvorenog ugla je opisana umerenom do dobrom povezano&scaron;ću sa stepenom o&scaron;tećenja vidnog polja, pri čemu je ona najjača kod TPeriF, IPeriF i SPeriF segmenata i srazmerna je stepenu o&scaron;tećenja vidnog polja. Koeficijenti korelacije između vrednosti srednje devijacije vidnog polja i debljine RNFL, odnosno&nbsp; sloja nervnih vlakana makule, pokazuju snažniju povezanost u odnosu na parametre dobijenog smanjenja debljine nervnih vlakana u makuli, &scaron;to otvara mogućnost za dalja istraživanja. Segmenti glave vidnog živca i makule, koji su pokazali najbolju diskriminaciju u smislu predikcije nastanka POAGa, kao i oni koji sugeri&scaron;u na njegovu progresiju, sme&scaron;teni su na lokacijama koje su međusobno povezane opisanim prirodnim tokom nervnih vlakana.&nbsp; Zaključak: Optička koherentna tomografija makule je važna pomoćna metoda u dijagnostici glaukoma kojom je moguće izdvojiti pacijente sa ranim glaukomom u odnosu na zdravu populaciju, odnosno utvrditi progresiju glaukoma otvorenog ugla.</p> / <p>All patients underwent complete ophthalmologic examination, SAP (Humphrey Field Analyzer, Carl Zeiss Meditec, Jena, Germany, SITA Standard, test C 24-2) and optical coherent tomography scans of RNFL and macula (SOCT Copernicus HR, Optopol Tech. SA, Zawiercie, Poland). Results: Perifoveal and parafoveal nerve fiber layer have shown significant reduction of thickness and volume compared to stage of POAG progression, where perifovea showed higher significance (p&lt;0,05). All macular segments (TPeriF, IPeriF, SPeriF, NPeriF, TParaF, SParaF, IParaF i NParaF) showed reduction in thickness and volume compared to disease progression (p&lt;0,05). Macular segments TPeriF, IPeriF, as well as SPeriF, represent segments with highest potential to predict early glaucomatous damage according to the most significant reduction of nerve fiber layer thickness and volume (p&lt;0,05). Macular segments SParaF and NParaF represent segments with highest potential to predict progression of POAG according to the most significant reduction of nerve fiber layer thickness and volume (p&lt;0,05). Optic nerve head (ONH) RNFL thickness showed reduction compared to POAG progression in all segments (p&lt;0,05). All ONH segments except P3 and P4 showed significant reduction of RNFL comparing control group to early glaucoma group patients (p&gt;0,05). ONH segment P6 was found to be the highly specific for early glaucoma prediction according to the most significant reduction of RNFL thickness (p&lt;0,05), while segment P1 was found to have highest potential for POAG progression. Macular nerve fiber layer thickness reduction follows ONH RNFL thickness reduction and there is mutual relation between both macular and ONH segments (P6 to IPeriF and TPeriF, P1 to SPeriF) with highest specificity for early defects and POAG progression. It was shown that macular thickness changes have moderate to good correlation with visual filed changes and it was highest in TPeriF, IPeriF and SPeriF segments. This correlation was found to be higher in macula then in ONH RNFL thickness changes, compared to visual field changes. Both macular and ONH RNFL segments, which were found to have highest specificity to POAG prediction and progression, are located in areas which mutually connect following natural course of nerve fiber layer between them. Conclusion: Optical coherence tomography of macula represents important ancillary method in POAG diagnosis and follow up, allowing to differentiate between early glaucoma patients and healthy individuals, as well as to determine progression of glaucomatous disease.</p>
37

Morfološke karakteristike makule kao prognostički faktor poboljšanja vidne oštrine u terapiji pacijenata obolelih od dijabetesnog makularnog edema / Morphological characteristics of the macula as a prognostic factor of visual acuity improvement in the treatment of patients with diabetic macular edema

Džinić Vladislav 26 September 2016 (has links)
<p>Cilj ovog istraživanja je da se ispita uticaj centralne debljine makularne regije (CMT) i prisustva subretinalne tečnosti na vidnu o&scaron;trinu (VA) kod pacijenata obolelih od dijabetesnog makularnog edema, kao i uticaj očuvanosti kontinuiteta spoja spolja&scaron;njeg i unutra&scaron;njeg segmenta fotoreceptora (IS/OS &ndash; kompleks) i spolja&scaron;nje granične membrane (ELM) kao prognostičkih faktora u pobolj&scaron;anju vidne o&scaron;trine nakon primenjene terapije kod pacijenata obolelih od dijabetesnog makularnog edema (DME). Materijal i metode: u ovu retrospektivno prospektivnu kliničku studiju nasumično je uključeno 100 pacijenata koji su podeljeni u dve grupe. Grupu A &ndash; prospektivni deo studije je činilo 50 pacijenata (50 očiju) kod kojih je dijagnostikovan dijabetesni makularni edem i kod kojih je inidikovana primena terapije, laserftotkogaulacije i/ili anti-VEGF terapije (bevacizumab). Grupu B &ndash; retrospektivnu grupu je činilo 50 pacijenata (58 očiju) koji su prethodno lečeni od dijabetesnog makularnog edema primenom laserfotokoagulacije i/ili anti-VEGF terapije (bevacizumab). Nakon kompletnog oftalmolo&scaron;kog pregleda koji se sastojao od određivanja vidne o&scaron;trine (optotipima po Snellenu), biomikroskopije, merenja intraokularnog pritiska i pregleda očnog dna &ndash; fundusa primenom panfundoskopa izvr&scaron;ena je optička koherentna tomografija u svih pacijenata (primenom aparata Stratus&reg; OCT, Carl Zeiss, Meditec i Copercnicus&reg; Optopol). Analiza OCT snimka, je obuhvatila određivanje centralne debljine makule (CMT), prisustva subretinalne tečnosti kao i procenu stanja očuvanosti kontinuiteta spoja spolja&scaron;enjeg i unutra&scaron;njeg segmenta fotoreceptora (IS/OS kompleks) i očuvanost kontinuiteta spolja&scaron;nje granične membrane (ELM). CMT je izračunat primenom softvera OCT aparata i izražen kao srednja vrednost za svih 9 ETDRS polja. Prisutvno subretinalne tečnosti je klasifikovano kao pozitivno ukoliko je identifikovano makar u jednom preseku OCT tomograma .Očuvanost kontinuiteta IS/OS kompleksa i ELM je analizirana u svakom pojedinačnom snimku i podeljena u 3 kategorije. Prva &ndash; ukoliko je očuvano u svim presecima, druga &ndash; ukoliko je očuvano samo u pojedinim presecima i treća &ndash; ukoliko se IS/OS kompleks i ELM nisu mogli identifikovati na nalazu OCT tomograma. Rezultati ukazuju da prisustvo subretinalne tečnosti pre primenjene terapije nema statistički značajnog uticaja na pobolj&scaron;anje vidne o&scaron;trine nakon primenjene terapije u pacijenata grupe A (pA=0,915), a statistička značajnost nije potvrđena ni kod pacijenata koji su prethodno tretirani od DME &ndash; grupa B (pB=0,772). Srednja vrednosti CMT i VA u pacijaneta grupe A iznosila je 474&mu;m&plusmn;140,67&mu;m odnosno 0.25&plusmn;0.20. Nakon primenjene terapije srednja vrednost vidnih o&scaron;trina iznosila je 0.41&plusmn;0.25, dok su vrednosti srednje vrednosti CMT iznosile 343.68&mu;m&plusmn;99.03&mu;m. Potvrđeno je statistički značajno pobolj&scaron;anje vidne o&scaron;trine nakon primenjene terapije (pVA=0,0001) i statistički značajno smanjenje centralne debljine makule (pCMT=0,0001). Korelacija VA sa vrednostima CMT pre primenjene terapije pokazuje statističku značajnost sa negativnom korelacijom (r=-0,391; p=0,005) dok se nakon primenjene terapije ne uočava statistički značajna korelacija (r=-0,047; p=0,746). Analizom vrednosti CMT pre primenjene terapije sa vrednostima VA nakon terapije se uočava statistički značajna negativna korelacija, odnosno veće vrednosti CMT pre primenjene terapije ograničavaju pobolj&scaron;anje vidne o&scaron;trine nakon primenjene terapije (r=-0,393; p=0,005). Evaluacija OCT tomograma, pre primenjene terapije, u pacijenata grupe A utvrđen je u potpunosti očuvan kontinuitet IS/OS kompleksa i ELM u svim presecima u 23 odnosno 27 očiju, u pojedinim presecima u 18 odnosno 16 očiju, i nije mogao biti identifikovan u 9 odnosno 7 očiju. U pacijenata grupe A nakon primenjene terapije uočava se statistički značajno pobolj&scaron;anje vrednosti VA u zavisnosti od očuvanosti kontinuiteta IS/OS kompleksa (F=5,550, p=0,007) i ELM (F=5,428, p=0,008). Univarijantna odnosno multivarjiantna analiza podataka za granične vrednosti vidnih o&scaron;trina od 0,1 i koraka pobolj&scaron;anja od 0,1 ukazuje na statističku značajnost prediktora IS/OS kompleksa (p=0,012 i p=0,032) i ELM (p=0,003 i p=0,018) u pobolj&scaron;anju vrednosti vidnih o&scaron;trina nakon primenjene terapije. Pacijenti sa očuvanim kontinuitetom IS/OS kompelsa u svim presecima imaju 9,5 puta (OR=9,500 ) veću &scaron;ansu za pobolj&scaron;anje VA nakon primenjene terapije u odnosu na pacijente gde kontinuitet IS/OS kompleksa nije uočljiv. Pacijenti sa očuvanim kontinuitetom IS/OS kompleksa u pojedinim presecima imaju 7 puta veću &scaron;ansu (OR=7,000) za pobolj&scaron;anje vidne o&scaron;trine nakon terapije u poređenju sa onima kod kojih IS/OS nije uočljiv. Pacijenti sa očuvanim kontinuitetom ELM u svim presecima imaju 34,5 puta (OR=34,500 ) veću &scaron;ansu za pobolj&scaron;anje vidne o&scaron;trine u odnosu na pacijente gde ELM nije uočljiv. Pacijenti sa očuvanim kontinuitetom ELM u pojedinim presecima imaju 18 puta veću &scaron;ansu (OR=18,000) za pobolj&scaron;anje VA nakon terapije u odnosu na one kod kojih ELM nije uočljiv. Pored statistički značajnog uticaja očuvanosti kontinuiteta IS/OS kompleksa i ELM na pobolj&scaron;anje vrednosti vidnih o&scaron;trina nakon primenjene terapije, uočava se i pozitvna korelacija između vidnih o&scaron;trina pre i nakon terapije (r=0,869; p=0,0001). U pacijenata grupe B srednja vrednost CMT odnosno VA iznosila je 253,72&mu;m&plusmn;75,27&mu;m odnosno 0,68&plusmn;0,29. Postoji statistički značajna razlika u vrednostima VA u odnosu na očuvanost kontinuiteta IS/OS kompleksa (F=107,913, p=0,0001) i ELM (F=25,619, p=0,0001). Poređenjem vrednosti parametara za obe posmatrane grupe uočava se statistički značajna razlika u vrednostima CMT koje su bile manje u grupi B (t=5,355, p=0,0001) i srednjim vrednostima VA ( t=5,137, p=0,0001) koje su bile veće u grupi B. Analizom očuvanosti kontinuiteta IS/OS kompleksa (&chi;2=0,119, p=0,730) i ELM (&chi;2=2,957, p=0,085) ne uočava se statistički značajna razlika. Zaključak: Odnos vidnih o&scaron;trina sa centralnom debljinom makule prikazuje različite vrednosti vidnih o&scaron;trina za iste vrednosti centralne debljine makule. Značajan uticaj na vidnu o&scaron;trinu pacijenata obolelih od DME ima očuvanost integriteta spolja&scaron;nje granične membrane (ELM) i spoja unutra&scaron;njeg i spolja&scaron;njeg segmenta fotoreceptora (IS/OS kompleks) evaluiranih na osnovu OCT snimka &ndash; tomograma. Očuvanost integriteta ELM i IS/OS kompleksa u svim presecima na OCT tomogramu pre primenjene terapije u pacijenta sa DME se mogu smatrati pozitivnim prognostičkim faktorom u pobolj&scaron;anju vidne o&scaron;trine nakon primenjene terapije. U pacijenata kod kojih je kontinuitet ELM i IS/OS kompleksa očuvan u svim pravcima vrednost CMT pre primenjene terapije nema uticaj na pobolj&scaron;anje vidne funkcije nakon terapije. Integritet IS/OS kompleksa i ELM ima pozitivnu korelaciju sa vidnom o&scaron;trinom bez obzira na vrstu primenjene terapije, anti-VEGF odnosno laserfotokoagulacije. Prisustvo subretinalne tečnosti ne utiče na vidnu o&scaron;trinu pacijenata obolelih od DME. Vrednosti VA pre terapije utiču na pobolj&scaron;anje vidne o&scaron;trine nakon terapije.</p> / <p>The aim of this study was to investigate the influence of the central macular thickness (CMT) and the presence of sub retinal fluid on visual acuity (VA) in patients with diabetic macular edema, as well as the impact of preservation and continuity of the photoreceptor inner/outer segment junction (IS / OS - complex ) and external limiting membrane (ELM) as a prognostic factor in improving visual acuity after the applied therapy in patients with diabetic macular edema (DME). Materials and Methods: this retrospective - prospective randomized clinical study included 100 patients who were divided into two groups. Group A - a prospective part of the study, consisted of 50 patients (50 eyes), with the diagnosis of diabetic macular edema in which laser photocoagulation and / or anti-VEGF therapy (bevacizumab) was indicated. Group B - retrospective group, consisted of 50 patients (58 eyes), who were previously treated for diabetic macular edema either with laser photocoagulation and / or anti-VEGF therapy (bevacizumab). After complete ophthalmologic examination, which consisted of the determination of visual acuity (measured with Snellen charts), biomicroscopy, intraocular pressure measurement and inspection of the fundus, optical coherence tomography was performed in all patients (using the Stratus&reg; OCT, Carl Zeiss Meditec and Copercnicus&reg; Optopol). Analysis of OCT image, included the determination of the central macular thickness (CMT), presence of sub retinal fluid, as well as an assessment of the preservation of the continuity of the photoreceptor inner/outer segment junction (IS/OS - complex) and external limiting membrane (ELM). CMT is calculated using software of the OCT apparatus and expressed as the mean value for all 9 ETDRS fields. Presence of sub retinal fluid is classified as positive if it is identified in at least one cross-section of OCT tomogram. Preserved continuity of IS / OS complex and ELM is analyzed in each individual OCT cross-section image and divided into 3 categories. First - if it is preserved in all cross sections images, the second - if it is preserved only in certain sections and the third - if the IS / OS complex and ELM were not able to identify in OCT tomograms. The results indicate that the presence of sub retinal fluid before the applied therapy has no statistically significant effect on improving visual acuity after the applied therapy in patients of group A (pA = 0.915), and statistical significance was not also confirmed in any of the patients who were previously treated by DME - Group B (pB = 0.772). Mean CMT and VA values of patients in group A was 474&mu;m &plusmn; 140,67&mu;m and 0.25 &plusmn; 0.20. After receiving therapy mean visual acuity was 0.41 &plusmn; 0.25, while the value of the mean CMT was 343.68&mu;m&plusmn; 99.03&mu;m. Significant improvement in visual acuity was achieved after the treatment in group A (pVA = 0.0001) together with statistically significant reduction in central macular thickness (pCMT = 0.0001). Correlation of VA with the values of CMT before applied therapy shows statistically significant negative correlation (r = -0.391; p = 0.005), while after the applied therapy statistical significance was not observed (r = -0.047; p = 0.746). Analyzing the values of CMT before the applied therapy with the values of VA after the treatment statistically significant negative correlation was observed, higher values of CMT before the applied therapy restrict visual acuity improvement after the applied therapy (r = -0.393; p = 0.005). Analyzing OCT tomograms in the patients in group A, before the applied therapy, fully preserved continuity of IS/OS complex and ELM in all the sections was found in 23 and 27 of the eyes, in certain sections in 18 and 16 of the eyes, and could not be identified in 9 and 7 eyes. Statistically significant improvement in VA, after the applied therapy, in patients in group A is observed, depending on the preservation of continuity of IS/OS complex (F = 5.550, p = 0.007) and ELM (F = 5.428, p = 0.008). Univariate and multivariate analysis with cut off VA value of 0.1 and step improvements of 0.1 points to statistically significant predictor of IS/OS complex (p = 0.012 and p = 0.032) and ELM (p = 0.003 and p = 0.018) in improving the VA after the applied therapy. Patients with preserved continuity of IS/OS complex in all sections are 9.5 times (OR = 9.500) more likely to improve the VA after receiving therapy compared to patients where continuity of IS/OS complex is not noticeable. Patients with preserved continuity of IS/OS complex in the some sections are 7 times more likely (OR = 7.000) for the improvement of visual acuity after treatment compared to those in which the IS/OS is not detectable. Patients with preserved continuity of ELM in all sections are 34.5 times (OR = 34,500) a greater chance to improve visual acuity compared to patients where ELM is not apparent. Patients with preserved continuity of ELM in the some sections are 18 times more likely (OR = 18,000) to improve the VA after treatment compared to those in which the ELM is not apparent. In addition to statistically significant impact of preservation of continuity of IS/OS complex and ELM for VA improvement after the treatment, statistically significant positive correlation between visual acuity before and after treatment (r = 0.869; p = 0.0001) was observed. In Group B patients, the mean CMT and VA value was 253,72&mu;m&plusmn;75,268&mu;m and 0.68 &plusmn; 0.29. There is a statistically significant difference in the VA values compared to the preservation of continuity of IS/OS complex (F = 107.913, p = 0.0001) and ELM (F = 25.619, p = 0.0001). Comparing the values of parameters for both groups, statistically significant difference in CMT values and mean VA was observed. CMT values were lower (t = 5.355, p = 0.0001) while VA values were higher (t = 5.137, p = 0.0001), in group B. The analysis of preservation of continuity of IS/OS complex (&chi;2 = 0.119, p = 0.730) and ELM (&chi;2 = 2.957, p = 0.085) did not show a statistically significant difference. Conclusion: The relationship of visual acuity with central macular thickness shows the different levels of visual acuity for the same value of the central macular thickness. A significant impact on VA in patients with DME has maintained integrity of the external limiting membrane (ELM) and the photoreceptors inner/outer segments junction (IS/OS complex) evaluated on the basis of OCT - tomograms. Preservation of the integrity of the ELM and IS/OS complex in all sections of the OCT tomogram before applied therapy in patients with DME can be considered a positive prognostic factor in improving visual acuity after receiving therapy. In patients with preserved continuity of ELM and IS/OS complex in all sections before applied therapy the CMT value has no effect on the improvement of visual function after treatment. Regardless of the type of applied therapy, anti-VEGF and/or laser photocoagulation preserved integrity of IS/OS complex and ELM has a positive correlation with visual acuity. The presence of sub retinal fluid does not affect the visual acuity in patients with DME. The values of VA before treatment influence the improvement of visual acuity after treatment.</p>
38

Comparação das medidas da espessura macular e da camada de fibras nervosas retiniana para detecção de atrofia em banda do nervo óptico através da tomografia de coerência óptica / Comparison of macular thickness and retinal nerve fiber thickness measurements for detection of band atrophy of the optic nerve using optical coherence tomography

Moura, Frederico Castelo 31 August 2007 (has links)
Pacientes com compressão quiasmática apresentam perda das fibras nervosas da retina nasal que decussam no quiasma óptico. Por conseguinte, ocorre perda das fibras nervosas, predominantemente, no setor nasal e temporal do disco óptico, que se manifesta por atrofia em banda do nervo óptico ao exame oftalmoscópico e hemianopsia temporal ao exame de campo visual. Trabalhos anteriores mostraram que o tomógrafo de coerência óptica é capaz de diferenciar pacientes com atrofia em banda do nervo óptico associada à hemianopsia temporal completa de indivíduos normais através da análise da camada de fibras nervosas peripapilar. Estudos em glaucoma têm sugerido que a avaliação da espessura macular poderia ser útil na quantificação da perda neural como um método alternativo ou complementar ao estudo da camada de fibras nervosas da retina. No presente estudo, a espessura macular e da camada de fibras nervosas foram avaliadas pelo tomógrafo de coerência óptica em pacientes com atrofia em banda do nervo óptico e graus variados de hemianopsia temporal. O desempenho dos parâmetros maculares para detecção da atrofia em banda do nervo óptico foi avaliado pela área sob a curva ROC (AROC) e sensibilidades para especificidades fixas e os resultados foram comparados aos parâmetros da camada de fibras nervosas peripapilar. Para identificar os parâmetros do Stratus OCT que apresentaram melhor desempenho para diferenciar pacientes com AB do nervo óptico de indivíduos normais, modelos de regressão logística foram utilizados. A correlação estrutura-função foi realizada entre o grau do defeito temporal e os valores de espessura macular e da camada de fibras peripapilar através do coeficiente de correlação de Spearman. A categorização diagnóstica dos parâmetros da camada de fibras nervosas através do banco de dados normativos foi avaliada pelos valores de sensibilidade e especificidade calculados pelo teste exato de Fisher. Quarenta e quatro olhos com atrofia em banda e 47 olhos normais foram avaliados no estudo. Entre os parâmetros maculares, os parâmetros da retina nasal apresentaram melhor desempenho para detectar atrofia em banda do nervo óptico comparados aos parâmetros da retina temporal. Não houve diferença significante (p=0,32) entre as áreas sob a curva ROC do melhor parâmetro macular (AROC=0,97) e do melhor parâmetro da camada de fibras nervosas retiniana (AROC=0,99). Na avaliação da correlação estrutura-função, os parâmetros da retina nasal apresentaram maior correlação com o defeito campimétrico comparados aos parâmetros da camada de fibras nervosas da retinal. Entre os parâmetros maculares, a espessura nasal média apresentou a maior correlação (rs=0,618). Entre os parâmetros da camada de fibras nervosas da retina, a espessura média apresentou a maior correlação (rs=0,479). Os parâmetros espessura média, espessura nasal e espessura temporal da camada de fibras nervosas da retina apresentaram melhor desempenho diagnóstico baseado na categorização diagnóstica do banco de dados normativos. Os resultados obtidos no estudo mostraram que os parâmetros maculares discriminam olhos com atrofia em banda do nervo óptico em pacientes com graus variados de defeito temporal. Além disso, os parâmetros da retina nasal podem colaborar com o exame perimétrico e os parâmetros da camada de fibras nervosas para o seguimento dos pacientes com compressão quiasmática. / Patients with chiasmal compression present damage of crossed fibers of nasal retina. Therefore, retinal nerve fiber layer loss occurs predominantly on the nasal and temporal sides of the optic disc, a pattern that can be identified on ophthalmoscopy as band atrophy of the optic nerve and on visual field as temporal hemianopia. Previous studies have been demonstrated that optical coherence tomography is able to detect retinal nerve fiber layer loss in patients with lesions of the optic chiasm and complete temporal hemianopia. Studies in glaucoma have been suggested that macular thickness measurements could be useful in quantification of optical nerve axonal loss as alternative or complement method to evaluate the retinal nerve fiber layer. The purpose of the present study was to compare macular thickness and retinal nerve fiber thickness measurements in patients with band atrophy of the optic nerve and different severities of visual field defect using optical coherence tomography. Area under the receiver operating characteristic curve (AROC) and sensitivities at fixed specificities were performed for evaluation of diagnostic accuracy of macular and retinal nerve fiber layer parameters. To identify the best optical coherence tomography measurements to differentiate band atrophy of the optic nerve patients from normal individuals, logistic regression models were performed. Association between optical coherence tomography parameters and temporal field defect were examined by Spearman coefficient of correlation. Fisher\'s exact test was performed to evaluate diagnostic ability of retinal nerve fiber parameters by optical coherence tomography in eyes with band atrophy using comparison with its internal normative database. A total of 44 eyes with band atrophy of the optic nerve and 47 normal eyes were studied. Among macular parameters, nasal retina measurements showed diagnostic accuracy better than temporal retina measurements. No statistically significant difference (p=0.32) was found between areas under ROC curve for the best macular parameter (AROC=0.97) and the best retinal nerve fiber layer parameter (AROC=0.99). Nasal retina parameters correlations were higher than retinal nerve fiber parameters. The highest correlation was observed for the mean nasal thickness (rs=0.618) for macular parameters. In retinal nerve fiber parameters, the highest correlation was observed for the average thickness (rs=0.479). In evaluation of diagnostic ability of normative database, the average thickness parameter demonstrated the highest sensitivity for detection of abnormalities in eyes with band atrophy, followed by the parameters related to the nasal and temporal quadrants. These results suggest that macular thickness measurements discriminate eyes with band atrophy of the optic nerve with different severities of temporal field defect. Results also suggest that nasal retina thickness measurements could potentially be used to evaluate retinal ganglion cell loss in patients with chiasmal compression.
39

Comparação das medidas da espessura macular e da camada de fibras nervosas retiniana para detecção de atrofia em banda do nervo óptico através da tomografia de coerência óptica / Comparison of macular thickness and retinal nerve fiber thickness measurements for detection of band atrophy of the optic nerve using optical coherence tomography

Frederico Castelo Moura 31 August 2007 (has links)
Pacientes com compressão quiasmática apresentam perda das fibras nervosas da retina nasal que decussam no quiasma óptico. Por conseguinte, ocorre perda das fibras nervosas, predominantemente, no setor nasal e temporal do disco óptico, que se manifesta por atrofia em banda do nervo óptico ao exame oftalmoscópico e hemianopsia temporal ao exame de campo visual. Trabalhos anteriores mostraram que o tomógrafo de coerência óptica é capaz de diferenciar pacientes com atrofia em banda do nervo óptico associada à hemianopsia temporal completa de indivíduos normais através da análise da camada de fibras nervosas peripapilar. Estudos em glaucoma têm sugerido que a avaliação da espessura macular poderia ser útil na quantificação da perda neural como um método alternativo ou complementar ao estudo da camada de fibras nervosas da retina. No presente estudo, a espessura macular e da camada de fibras nervosas foram avaliadas pelo tomógrafo de coerência óptica em pacientes com atrofia em banda do nervo óptico e graus variados de hemianopsia temporal. O desempenho dos parâmetros maculares para detecção da atrofia em banda do nervo óptico foi avaliado pela área sob a curva ROC (AROC) e sensibilidades para especificidades fixas e os resultados foram comparados aos parâmetros da camada de fibras nervosas peripapilar. Para identificar os parâmetros do Stratus OCT que apresentaram melhor desempenho para diferenciar pacientes com AB do nervo óptico de indivíduos normais, modelos de regressão logística foram utilizados. A correlação estrutura-função foi realizada entre o grau do defeito temporal e os valores de espessura macular e da camada de fibras peripapilar através do coeficiente de correlação de Spearman. A categorização diagnóstica dos parâmetros da camada de fibras nervosas através do banco de dados normativos foi avaliada pelos valores de sensibilidade e especificidade calculados pelo teste exato de Fisher. Quarenta e quatro olhos com atrofia em banda e 47 olhos normais foram avaliados no estudo. Entre os parâmetros maculares, os parâmetros da retina nasal apresentaram melhor desempenho para detectar atrofia em banda do nervo óptico comparados aos parâmetros da retina temporal. Não houve diferença significante (p=0,32) entre as áreas sob a curva ROC do melhor parâmetro macular (AROC=0,97) e do melhor parâmetro da camada de fibras nervosas retiniana (AROC=0,99). Na avaliação da correlação estrutura-função, os parâmetros da retina nasal apresentaram maior correlação com o defeito campimétrico comparados aos parâmetros da camada de fibras nervosas da retinal. Entre os parâmetros maculares, a espessura nasal média apresentou a maior correlação (rs=0,618). Entre os parâmetros da camada de fibras nervosas da retina, a espessura média apresentou a maior correlação (rs=0,479). Os parâmetros espessura média, espessura nasal e espessura temporal da camada de fibras nervosas da retina apresentaram melhor desempenho diagnóstico baseado na categorização diagnóstica do banco de dados normativos. Os resultados obtidos no estudo mostraram que os parâmetros maculares discriminam olhos com atrofia em banda do nervo óptico em pacientes com graus variados de defeito temporal. Além disso, os parâmetros da retina nasal podem colaborar com o exame perimétrico e os parâmetros da camada de fibras nervosas para o seguimento dos pacientes com compressão quiasmática. / Patients with chiasmal compression present damage of crossed fibers of nasal retina. Therefore, retinal nerve fiber layer loss occurs predominantly on the nasal and temporal sides of the optic disc, a pattern that can be identified on ophthalmoscopy as band atrophy of the optic nerve and on visual field as temporal hemianopia. Previous studies have been demonstrated that optical coherence tomography is able to detect retinal nerve fiber layer loss in patients with lesions of the optic chiasm and complete temporal hemianopia. Studies in glaucoma have been suggested that macular thickness measurements could be useful in quantification of optical nerve axonal loss as alternative or complement method to evaluate the retinal nerve fiber layer. The purpose of the present study was to compare macular thickness and retinal nerve fiber thickness measurements in patients with band atrophy of the optic nerve and different severities of visual field defect using optical coherence tomography. Area under the receiver operating characteristic curve (AROC) and sensitivities at fixed specificities were performed for evaluation of diagnostic accuracy of macular and retinal nerve fiber layer parameters. To identify the best optical coherence tomography measurements to differentiate band atrophy of the optic nerve patients from normal individuals, logistic regression models were performed. Association between optical coherence tomography parameters and temporal field defect were examined by Spearman coefficient of correlation. Fisher\'s exact test was performed to evaluate diagnostic ability of retinal nerve fiber parameters by optical coherence tomography in eyes with band atrophy using comparison with its internal normative database. A total of 44 eyes with band atrophy of the optic nerve and 47 normal eyes were studied. Among macular parameters, nasal retina measurements showed diagnostic accuracy better than temporal retina measurements. No statistically significant difference (p=0.32) was found between areas under ROC curve for the best macular parameter (AROC=0.97) and the best retinal nerve fiber layer parameter (AROC=0.99). Nasal retina parameters correlations were higher than retinal nerve fiber parameters. The highest correlation was observed for the mean nasal thickness (rs=0.618) for macular parameters. In retinal nerve fiber parameters, the highest correlation was observed for the average thickness (rs=0.479). In evaluation of diagnostic ability of normative database, the average thickness parameter demonstrated the highest sensitivity for detection of abnormalities in eyes with band atrophy, followed by the parameters related to the nasal and temporal quadrants. These results suggest that macular thickness measurements discriminate eyes with band atrophy of the optic nerve with different severities of temporal field defect. Results also suggest that nasal retina thickness measurements could potentially be used to evaluate retinal ganglion cell loss in patients with chiasmal compression.
40

OCT (Optical Coherense Tomography) : Teknik och tillämpning

Lundkvist, Stefan January 2013 (has links)
Before year 1895, the doctors could only make a probable diagnosis based on what the patient could tell and it was hurt and there was no discernable change to the outside of the body. With X-ray, it was possible to see inside the patient without first cutting it, you can say that the X-ray was the starting point for diagnostic imaging.The further development of X-ray gave CT (Computed Tomography), where X-ray tubes and detectors rotate around the patient while the patient table moves. Besides CT also developed MRI (Magnetic Resonance Imaging), PET (Positron Emission Tomography) and Ultrasound. Common to these methods is that the produced 3D images.In 1990 a completely new approach for diagnostic imaging, OCT (optical coherence tomography), by measuring the phase shift and the intensity of reflected light, it provides real-time and non-destructive measurements (in vivo) a resolution of 1 to 15 microns, much higher than all other standard imaging techniques. You could say that OCT machine can be compared to ultrasound, which uses the reflection of sound waves to interpretation.The first OCT machines were of type TD (Time Domain), these had low resolution and low scanning speed. In 2005 came the SD-OCT, they had higher resolution and scanning speed, SD stands for spectral domain, SD-OCT is sometimes called FD-OCT as Fourier transformed signals and operating in the frequency domain.The development of OCT machines are only in their infancy, resolution, scanning speed and accuracy will increase all the time, this allows new uses and ways to diagnose developed. OCT can be used in such Oncology, MSD (Musculoskeletal disorders), cardiovascular medicine, teeth, nerves, but the largest field is the eye and then the back of the eye called the retina (retina).This thesis is limited to the eye, the purpose is to provide input to those who are likely to purchase an OCT-machine, but also show the measurement data OCT-machines are performing and how to use the OCT-machine more than to see age-related macular degeneration. Another aim is to increase understanding of the physics behind an OCT-machine for ease of understanding the output given.The manufacture/model that have selected for evaluation are Zeiss Cirrus 4000, Topcon 3D OCT-2000 and Heidelberg Spectralis, the reason is that there are only these three on the Swedish market and all are SD-OCT. The way to evaluate OCT-machines is to scan performance and what the various analysis programs can handle. Furthermore, each OCT-machine scans the macula and optic disk on a experimental person/ reference eye, in order to get the output of the precision, or if you want to call it repeatability, which is very important if one wants to follow a solitary disease course.The conclusion of this thesis is to OCT machines are quite similar. When it comes to ease of use when doing scans is the Cirrus is lightened by the use of the extra screen where you always look eye (iris camera), which makes it easy to adjust the sharpness and position of the mouse buttons. Topcon and Heidelberg is not difficult to use but requires more experience of the person making the OCT scans. Most measurement functions in the analysis program is Topcon and Heidelberg and best accuracy/repeatability is Heidelberg, both the macula and RFNL.OCT machine is a good tool to use on the anterior segment, but in the case the precision allows the precision used to monitor RNFL thickness changes in those with glaucoma. / <p>Validerat; 20131029 (global_studentproject_submitter)</p>

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