PURPOSE. Gait during obstacle negotiation is adapted in visually normal subjects whose vision is temporarily and unilaterally blurred or occluded. This study was conducted to examine whether gait parameters in individuals with long-standing deficient stereopsis are similarly adapted. METHODS. Twelve visually normal subjects and 16 individuals with deficient stereopsis due to amblyopia and/or its associated conditions negotiated floor-based obstacles of different heights (7-22 cm). Trials were conducted during binocular viewing and monocular occlusion. Analyses focused on foot placement before the obstacle and toe clearance over it. RESULTS. Across all viewing conditions, there were significant group-by-obstacle height interactions for toe clearance (P < 0.001), walking velocity (P = 0.003), and penultimate step length (P = 0.022). Toe clearance decreased (similar to 0.7 cm) with increasing obstacle height in visually normal subjects, but it increased (similar to 1.5 cm) with increasing obstacle height in the stereo-deficient group. Walking velocity and penultimate step length decreased with increasing obstacle height in both groups, but the reduction was more pronounced in stereo-deficient individuals. Post hoc analyses indicated group differences in toe clearance and penultimate step length when negotiating the highest obstacle (P < 0.05). CONCLUSIONS. Occlusion of either eye caused significant and similar gait changes in both groups, suggesting that in stereo-deficient individuals, as in visually normal subjects, both eyes contribute usefully to the execution of adaptive gait. Under monocular and binocular viewing, obstacle-crossing performance in stereo-deficient individuals was more cautious when compared with that of visually normal subjects, but this difference became evident only when the subjects were negotiating higher obstacles; suggesting that such individuals may be at greater risk of tripping or falling during everyday locomotion. / RCUK (Research Councils, UK)

L’ère numérique change de plus en plus le monde en raison de la quantité de données récoltées chaque jour. Le domaine médical est fortement affecté par cette explosion, car l’exploitation de ces données est un véritable atout pour l’aide à la pratique médicale. Dans cette thèse, nous proposons d’utiliser les vidéos chirurgicales dans le but de créer un système de chirurgie assistée par ordinateur. Nous nous intéressons principalement à reconnaître les gestes chirurgicaux à chaque instant afin de fournir aux chirurgiens des recommandations et des informations pertinentes. Pour ce faire, l’objectif principal de cette thèse est de reconnaître les outils chirurgicaux dans les vidéos de chirurgie de la cataracte. Dans le flux vidéo du microscope, ces outils sont partiellement visibles et certains se ressemblent beaucoup. Pour relever ces défis, nous proposons d'ajouter une caméra supplémentaire filmant la table opératoire. Notre objectif est donc de détecter la présence des outils dans les deux types de flux vidéo : les vidéos du microscope et les vidéos de la table opératoire. Le premier enregistre l'oeil du patient et le second enregistre les activités de la table opératoire. Deux tâches sont proposées pour détecter les outils dans les vidéos de la table : la détection des changements et la détection de présence d'outil. Dans un premier temps, nous proposons un système similaire pour ces deux tâches. Il est basé sur l’extraction des caractéristiques visuelles avec des méthodes de classification classique. Il fournit des résultats satisfaisants pour la détection de changement, cependant, il fonctionne insuffisamment bien pour la tâche de détection de présence des outils sur la table. Dans un second temps, afin de résoudre le problème du choix des caractéristiques, nous utilisons des architectures d’apprentissage profond pour la détection d'outils chirurgicaux sur les deux types de vidéo. Pour surmonter les défis rencontrés dans les vidéos de la table, nous proposons de générer des vidéos artificielles imitant la scène de la table opératoire et d’utiliser un réseau de neurones à convolutions (CNN) à base de patch. Enfin, nous exploitons l'information temporelle en utilisant un réseau de neurones récurrent analysant les résultats de CNNs. Contrairement à notre hypothèse, les expérimentations montrent des résultats insuffisants pour la détection de présence des outils sur la table, mais de très bons résultats dans les vidéos du microscope. Nous obtenons des résultats encore meilleurs dans les vidéos du microscope après avoir fusionné l’information issue de la détection des changements sur la table et la présence des outils dans l’oeil. / The digital era is increasingly changing the world due to the sheer volume of data produced every day. The medical domain is highly affected by this revolution, because analysing this data can be a source of education/support for the clinicians. In this thesis, we propose to reuse the surgery videos recorded in the operating rooms for computer-assisted surgery system. We are chiefly interested in recognizing the surgical gesture being performed at each instant in order to provide relevant information. To achieve this goal, this thesis addresses the surgical tool recognition problem, with applications in cataract surgery. The main objective of this thesis is to address the surgical tool recognition problem in cataract surgery videos.In the surgical field, those tools are partially visible in videos and highly similar to one another. To address the visual challenges in the cataract surgical field, we propose to add an additional camera filming the surgical tray. Our goal is to detect the tool presence in the two complementary types of videos: tool-tissue interaction and surgical tray videos. The former records the patient's eye and the latter records the surgical tray activities.Two tasks are proposed to perform the task on the surgical tray videos: tools change detection and tool presence detection.First, we establish a similar pipeline for both tasks. It is based on standard classification methods on top of visual learning features. It yields satisfactory results for the tools change task, howev-lateer, it badly performs the surgical tool presence task on the tray. Second, we design deep learning architectures for the surgical tool detection on both video types in order to address the difficulties in manually designing the visual features.To alleviate the inherent challenges on the surgical tray videos, we propose to generate simulated surgical tray scenes along with a patch-based convolutional neural network (CNN).Ultimately, we study the temporal information using RNN processing the CNN results. Contrary to our primary hypothesis, the experimental results show deficient results for surgical tool presence on the tray but very good results on the tool-tissue interaction videos. We achieve even better results in the surgical field after fusing the tool change information coming from the tray and tool presence signals on the tool-tissue interaction videos.

O estudo teve como objetivos verificar em dois grupos de pacientes com visão monocular (grupo 1) e com visão binocular (grupo 2), a serem submetidos à cirurgia de catarata no Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, opiniões, expectativas e reações emocionais em relação ao problema ocular, à qualidade da visão e à cirurgia de catarata; influência da característica de apresentar visão mono ou binocular nas reações emocionais relacionadas à cirurgia de catarata. Foi realizado estudo transversal e comparativo, de forma consecutiva, por meio de questionário estruturado, aplicado por entrevista a pacientes, elaborado a partir de estudo exploratório e medidas acuidade visual e causa da perda visual. A amostra foi constituída por 96 indivíduos do grupo 1 (50,0% homens; 50,0% mulheres, com idade entre 41 e 91 anos, média 69,3 anos ± 10,4 anos) e 110, do grupo 2 (40,9% homens; 59,1% mulheres, com idade entre 40 e 89 anos, média 68,2 anos ± 10,2 anos). A maioria dos indivíduos de ambos os grupos apresentava baixa escolaridade. Não houve diferença estatisticamente significante entre os grupos em relação ao sexo (p = 0,191), à idade (p = 0,702) e à escolaridade (p = 0,245). Não exerciam atividade laboral 95,8% dos indivíduos do grupo 1 e 83,6%, do grupo 2 (p = 0,005) e 30,4% do grupo 1 mencionaram não ter possibilidade de trabalhar por causa da deficiência visual. Observou-se acuidade visual do olho a ser operado menor que 0,05 em 40,6% (grupo 1) e 33,6% (grupo 2), entre 0,25 e 0,05. Quase a totalidade dos indivíduos de ambos os grupos afirmou ter dificuldade para realização das atividades de vida diária e qualificou como insuficiente a respectiva acuidade visual; 71,9% dos entrevistados do grupo 1 e 71,6%, do grupo 2 mencionaram saber a causa da visão fraca; desses, 87,1% do grupo 1 e 83,3% do grupo 2 referiram a catarata como causa da baixa acuidade visual. No que se refere ao medo, 40,6% dos indivíduos do grupo 1 e 22,7%, do grupo 2, relataram ter medo do procedimento cirúrgico (p = 0,009). As causas de medo mais referidas foram: possibilidade de perder a visão; piorar a visão; sofrer alguma complicação na cirurgia; morrer durante a cirurgia. Os sentimentos mais preponderantes entre os grupos foram: satisfação por saber que a catarata pode ser operada e melhorar a visão, alívio por saber que vai ser operado, dúvida quanto a ter bom resultado, nervosismo. Referiram esperar que mudanças ocorressem na vida após a cirurgia 90,6% (grupo 1) e 84,6% (grupo 2). Quanto às atividades que esperavam realizar após a cirurgia mencionaram: realizar serviços de casa; ler; sair sozinho. Concluiu-se que: os indivíduos de ambos os grupos tiveram acesso à cirurgia de catarata com acuidade visual menor do que a idealmente indicada; os pacientes com visão monocular apresentaram acuidade visual significativamente menor em relação aos com visão binocular; a maioria dos entrevistados de ambos os grupos referiu dificuldades para realizar atividades cotidianas como conseqüência da baixa visão; os indivíduos com visão monocular referiram mais dúvida em relação aos resultados cirúrgicos do que os com visão binocular; muitos indivíduos de ambos os grupos desconheciam a causa da dificuldade visual ou a atribuíram a outra causa que não a catarata; indivíduos de ambos os grupos apontaram expectativas positivas em relação à reabilitação após a cirurgia. / The purpose of the study was to verify in two groups of patients with monocular vision (group 1) and with binocular vision (group 2) to be submitted to cataract surgery in Hospital das Clínicas, São Paulo University Medical School, opinions, expectances and emotional reactions related to the ocular problem, to the quality of vision and to cataract surgery, the influence of monocular or binocular vision in the emotional reactions related to cataract surgery. A transversal comparative and consecutive study was performed using a structured questionnaire applied by interview of patients. The questionnaire was elaborated from a previous exploratory study, the visual acuity and cause of the visual loss were evaluated. The sample was constituted by 96 persons of group 1 (50% males; 50% females, ages ranging from 41 to 91 years old; average 69,3 years ± 10,4 years) and 110 persons of group 2 (40,9% males; 59,1% females, ages ranging from 40 to 89 years old; average 68,2 years ± 10,2 years). The majority of persons of both groups presented low educational level. There was no statistically significant difference between the groups in relation to gender (p = 0,191), age (p = 0,702) and educational level (p = 0,245). No work activity was mentioned in 95,8% of the persons of group 1 and 83,6% of group 2 (p = 0,005) and 30,4% of group 1 informed the impossibility to work due the visual deficiency. It was observed that the visual acuity of the eye to be operated was less than 0,05 in 40,6% (group 1) and in 33,6% (group 2), presented visual acuity ranging from 0,05 to 0,25. Almost the totality of the persons of both groups informed difficulties to perform activities of daily life and qualified as insufficient their visual acuities; 71,9% of the patients of group 1 and 71,6% of group 2 informed to know the reason of low vision; among these, 87,1% of group 1 and 83,3% of group 2 mentioned cataract as the reason of low visual acuity. Concerning fear, 40,6% of patients of group 1 and 22,7% of group 2 informed about fear of the surgical procedure (p = 0,009). The causes of fear more frequently reported were: possibility of loss of vision; worsening of vision; complications during the surgical procedure and to die during the surgery. The more preponderant feelings in both groups were: satisfaction knowing that a cataract can be operated with improvement of vision, relief knowing that will be submitted to surgery, doubt about a good result, nervousness. Changes in the life after surgery were mentioned by 90,6% (group 1) and by 84,6% (group 2) of the persons. Housework activities, reading and moving around without help were the mentioned activities expected to be performed after surgery. It was concluded that the patients of both groups were submitted to cataract surgery with visual acuities less than the visual acuity ideally indicated; the patients with monocular vision showed visual acuities significantly less in relation to the patients with binocular vision; the majority of the patients of both groups mentioned difficulties to perform daily activities as a consequence of low vision; patients with monocular vision mentioned doubts in relation to the surgical results as compared with the patients with binocular vision; many patients of both groups did not know the cause of the visual difficulty or explained the visual difficulty by other cause than the cataract; patients of both groups were positively expectant in relation to the visual rehabilitation after the surgery.

Introdução: A partir de relatos casos de opacifiação da lente intraocular acrílica hidrofílica Ioflex (Mediphacos, Belo Horizonte, Brasil), muitas vezes utilizada em mutirões de catarata para pessoas carentes, avaliamos a frequência das complicações oculares relacionadas com o implante desta lente quatro anos após a cirurgia, bem como seus efeitos a longo prazo na eficiência da cirurgia de catarata. Métodos: Foi selecionada amostra aleatória com 102 indivíduos submetidos à cirurgia de catarata com implante da lente intraocular Ioflex, em campanha comunitária no interior de Pernambuco, Brasil, quatro anos após a cirurgia. Um total de 31 pacientes não foi localizado e treze (18,3%) não compareceram para o exame. Assim, 58 pacientes (87 olhos) foram examinados. Para o cálculo da frequência da opacificação da cápsula posterior e para a avaliação da eficiência da cirurgia da catarata, foi selecionado apenas um olho de cada paciente. Os sujeitos foram submetidos a exame oftalmológico completo. Pacientes com redução da acuidade visual decorrentes das complicações pós-operatórias foram encaminhados para tratamento. O custo desses eventuais tratamentos foi estimado para análise da eficiência da cirurgia de catarata com a lente Ioflex. Para avaliação dos índices de opacificação da cápsula posterior as variáveis foram expressas por média e desvio padrão. Foi usado o teste t de Student\'s para análise de diferenças entre amostras independentes e pareadas. Resultados: Seis olhos (7%) apresentaram opacificação da lente intraocular. Nenhuma doença ou fator ambiental foi relacionado à opacificação da lente. A opacificação da cápsula posterior foi detectada em 39 (67%) olhos, sendo 24 (41,3%) olhos submetidos ao tratamento com laser para recuperação da acuidade visual. O custo total do tratamento das complicações pós-operatórias representou 6,3% do orçamento cirúrgico inicial. O custo adicional foi de $9,03 dólares por paciente para manter a boa acuidade visual. Conclusão: A lente intraocular acrílica hidrofílica Ioflex apresentou elevada frequência de complicações pós-operatórias tardias relacionadas à própria lente, reduzindo, a longo prazo, a eficácia e eficiência da cirurgia de catarata / Introduction: Based on reports of Ioflex hydrophilic acrylic intraocular lens opacification (Mediphacos, Belo Horizonte, Brazil), used in cataract surgeries for underserved communities, we evaluated the ocular complications related to the intraocular lens implant, four years after surgery, as well as its effects on the visual efficiency of long-term cataract surgery. Methods: A random sample of 102 patients that underwent cataract surgery and Ioflex intraocular lens implantation, in a community campaign in the rural area from Pernambuco, Brazil, four years after surgery. A total of 31 patients could not be located and 13 (18.3%) were not present for examination. Thus, 58 patients (87 eyes) were available for examination. In order to calculate the frequency of posterior capsule opacification and to evaluate the efficiency of cataract surgery, only one eye was selected from each patient. The subjects underwent a complete ophthalmological examination. Patients with reduced visual acuity due to postoperative complications were referred for treatment. The costs of these treatments were estimated for the analysis of the efficiency of the cataract surgery with the Ioflex lens in the long term period. For the evaluation of posterior capsule opacification rates the variables were expressed by means and standard deviation. The Student\'s t test was used for analysis the differences between independent and paired samples. Results: Six eyes (7.0%) had intraocular lens opacification. No disease or environmental factor could be related to intraocular lens opacification. Posterior capsule opacification was detected in 39 (67%) eyes, and 24 (41.3%) eyes were submitted to laser treatment for visual acuity recovered. The total cost of postoperative complications treatment represented 6.3% from the initial budget of the whole patients group evaluated. The additional costs to maintain a good visual outcome was USD $9.03 per patient with Ioflex lens implantation. Conclusion: The Ioflex hydrophilic acrylic intraocular lens had high rates of postoperative complications related to the intraocular lens itself, decreasing effectiveness efficiency in long-term cataract surgery

The dissertation describes the method of inserting polar-axis system into the video recording of cataract operation at the Geminy Eye Surgery, Zlin. At the theoretical part, it discusses requirements for inserting the polar-axis system including elimination of eye rotary movements captured by slit lamp. Then the emphasis is also on the speed of data processing. The practical part of the dissertation, focuses on the creating the method for detection of centers at the slit lamp picture, as well as video sequence and a method that eliminates potential eye rotation. For designing the program solution, following methods were used: Otsu method, Hough transformation method, method of two vertical projections, and crosscorrelation method. In total, the program solution was tested and analyzed in Matlab program on anonymous data set of 22 eyes.

Pseudoexfoliation (PEX) syndrome is an age-related condition characterized by the production and accumulation of extracellular fibrillary material in the anterior segment of the eye. PEX predisposes for several pathological conditions, such as glaucoma and complications during and after cataract surgery. The pathogenesis of PEX is not yet fully understood. It is multifactorial with genetics and ageing as contributing factors. We aimed to study the proteome in aqueous humor (AH) in PEX in order to increase the knowledge about its pathophysiology. Therefore, we developed sampling techniques and evaluated separation methods necessary for analyzing small sample volumes. Other objectives were to study the lens capsule in eyes with PEX regarding small molecules, and to investigate the association between PEX and cataract surgery in a population-based 30-year follow-up study. Samples of AH from eyes with PEX and control eyes were collected during cataract surgery. In pooled, and individual samples, various liquid based separation techniques and high resolution mass spectrometry were utilized. For quantitation, various methods for labeling, and label free techniques were applied. Lens capsules were collected from some of the patients, and analysed by imaging mass spectrometry. A cohort of 1,471 elderly individuals underwent a comprehensive ophthalmological examination at baseline. Medical information was obtained by questionnaires, and from medical records. Incident cases of cataract surgery were identified by review of medical records. In the initial study, several techniques were explored for protein detection, and a number of proteins were identified as differentially expressed. In the individually labelled samples, changes in the proteome were observed. Eyes with PEX contained higher levels of proteins involved in inflammation, oxidative stress, and coagulation, suggesting that these mechanisms are involved in the pathogenesis in PEX. The levels of β/γ-crystallins were significantly increased in PEX, which is a novel finding. In the lens capsules from individuals with PEX, changes in the lipid composition was observed with time-of-flight secondary ion mass spectrometry. These changes remain to be elucidated. By multivariate analysis, lens opacities were the first, and PEX the second most important predictor for cataract surgery, the later accounting for a 2.38-fold increased risk for cataract surgery.

No description available.

This is a study on the prevalence of refractive errors and patients requiring refractive services at 15 eye clinics in the Amathole, Chris Hani, Joe Gqabi and OR Tambo District Municipalities of the Eastern Cape. This is an area characterised by extreme poverty where the cost of an eye examination and prescription spectacles remains financially unobtainable for most. Optometry services are provided mainly by private optometrists who service the small proportion of the population that can afford them. Adults and children remain house bound or are labelled as dull and unproductive simply because they don’t have access to an eye examination and a pair of spectacles. Purpose The purpose of the study is to identify patients with refractive errors and those requiring refractive services at the 15 eye clinics in the Eastern Cape. Another purpose is to describe the refractive services that are available to patients attending health facilities, where the eye clinics are conducted. Lastly, the purpose is to explore the possibility of nurses providing refractive services independently or under the supervision of optometrists to supplement the lack to refracting and dispensing services. Study Method A quantitative and qualitative non-experimental descriptive design was used. Research involved the analysis of Vision Care’s eye clinic records collected from 15 eye clinics from January 2010-June 2010. Semi-structured interviews were conducted with 30 nurses working at the 15 health facilities where the eye clinics were conducted using purposive sampling. The quantitative data was analysed using excel spreadsheets and graphs and qualitative data was analysed using coding and categorizing methods. Conclusion According to Vision Care’s data of the patients assessed, 19.2 percent had a refractive error and 54 percent of the patients required refractive services. It is estimated that 71.41 percent of the patients had a refractive error according to the optometrist. Although there were some organisations active in the eradication of cataracts, there was little healthcare available in the form of refraction services. xiv Patients needed to travel an average of 63.8kms to access refraction services against the backdrop of poor roads, poverty and unemployment. 28 out of 30 nurses either ‘strongly agreed’ or ‘agreed’ that nurses could be trained to perform refractions and dispense spectacles. 29 out of 30 nurses thought that this would have a positive impact on eye care. Further research is necessary to assess the feasibility of implementing a nurse operated refractive program and whether it should be within their scope of practice to refract and dispense spectacles.