Thèse numérisée par la Division de la gestion de documents et des archives de l'Université de Montréal.

Objetivo: Investigar a influência do posicionamento da fóvea em relação à cabeça do nervo óptico (CNO) sobre resultados da perimetria padrão automatizada (PPA) central em pacientes com glaucoma e com defeitos patológicos localizados na rima temporal inferior (DTI) da CNO. Casuística e Métodos: Cinquenta e sete olhos de 35 pacientes com GPAA foram incluídos e divididos em dois grupos: um grupo com DTI (18 olhos) e outro com sem DTI (39 olhos). Três parâmetros diferentes obtidos a partir de uma tomografia de coerência óptica de domínio espectral (OCT-SD), ângulo do disco à fóvea (ADF), desvio vertical da fóvea (DVF) da linha média e diferença angular de defeito (DAD) entre borda DTI e ADF, foram correlacionados com quatro setores no programa 10-2: hemicampo superior, borda superior, borda nasal e arco súperonasal. As correlações foram testadas por meio de análises de regressão com modelos de efeitos mistos e interceptações aleatórias. Resultados: Os valores médios (± DP [Desvio padrão]) de ADF, DAD e DVF foram, respectivamente: -5,0 ± 4,4º, 43,3º ± 17,3º e -1346,6 µm ± 1609,0 µm. Comparações múltiplas mostraram que nos olhos com DTI, tanto DVF como DAD, mas não ADF, afetam significativamente os setores do campo visual (CV). As regressões binomiais de ROC demonstraram que apenas os valores de corte do 95º percentil de DVF (- 3264,5 µm) e DAD (70,5º) podem promover mudanças de sensibilidade na borda superior dos setores do programa 10-2 [DVF: AUC = 0,60 (95%CI = 0,50 - 0,71); DAD: AUC = 0,83 (IC 95% = 0,70 - 0,912)]. Conclusões: A localização vertical da fóvea e o seu posicionamento relativo aos limites do DTI interferiram nas alterações de sensibilidade de pontos periféricos do hemicampo superior, no programa 10-2. Como o ADF, isoladamente, não influenciou significativamente nessas alterações, outros ajustes utilizando posicionamento foveal e parâmetro da OCT devem ser considerados na avaliação da PPA central em pacientes com defeitos glaucomatosos localizados na CNO. / Purpose: To investigate the effects of the fóvea positioning relative to the optic disc on the 10-2 visual field (VF) in glaucoma patients with localized inferotemporal optic disc rim defects (ITD). Casuistic and Methods: Fifty-seven eyes of 35 POAG patients were included divided as having ITD (18 eyes) or not (39 eyes). Three different parameters obtained from a spectral domain optic coherence tomography (SD-OCT) [disc-fovea angle (DFA), fóvea vertical deviation (FVD) from midline, and defect\'s angular difference between ITD border and DFA (DAD)] were correlated to four 10-2 VF sectors: superior hemifield, superior edge, nasal edge, and supero nasal arch. Correlations were tested using regression analyses with mixed effects models and random intercepts. Results: Mean (±SD) values of DFA, DAD, and FVD were respectively: -5,0o ± 4.4o, 43.30o ± 17.33o, and -1346.6 µm ± 1609.0 µm. Multiple comparisons showed that in eyes with localized ITD both FVD and DAD, but not DFA, significantly affect the VF sectors. ROC binomial regressions demonstrated that only the 95th percentile cut-off values of FVD (-3264,5 µm) and DAD (70,5o) may influence changes in one (superior edge sensitivity) of the 10-2 VF sectors [FVD: AUC = 0,60 (95% CI = 0,50 - 0,71); DAD: AUC = 0,83 (95%CI = 0,70 - 0,912)]. Conclusions: The vertical fóvea location and its relative positioning to the limits of the ITD impact peripheral 10-2 VF points in the superior hemifield. As DFA itself did not show significant influences in the 10-2 VF, further adjustments using foveal positioning with OCT parameters should be considered in topographical analyses of the central VF in glaucoma patients with localized ITD.

Thèse numérisée par la Division de la gestion de documents et des archives de l'Université de Montréal

Multiple Sclerosis (MS) is a neurological autoimmune disease characterized by demyelination of central nervous system tissue and one way this is presented is in the demyelination of the retinal nerve, causing vision disturbance and loss (Munger et al., 2006). The thinning of the retinal nerve fiber layer (RNFL) can be measured and visualized using a noninvasive technique called Optical Coherence Tomography (OCT), which is also used to measure relative MS severity (Petzold et al., 2010). One environmental factor that has been found to have a relationship with MS is vitamin D; research findings suggest that sufficient levels of vitamin D may reduce the risk of developing MS, decrease MS severity, and may slow its progression (Ascherio et al., 2010; Munger et al., 2006; Muris et al., 2013). The mechanism by which vitamin D affects certain symptoms requires deeper investigation. This research examines the relationship between serum concentrations of 25-hydroxyvitamin D and retinal nerve fiber layer thicknesses in patients with MS. It was hypothesized that patients with sufficient vitamin D levels would have less demyelination of the retinal nerve caused by MS, and therefore would have a thicker RNFL in both eyes based on the proposed immunomodulatory role of vitamin D found in other studies. Blood samples were assayed to measure the concentration of 25-hydroxyvitamin D and OCT was used to measure RNFL thicknesses in patients with MS at the Harbor-UCLA Medical Center Neurology Clinic. Patients with sufficient levels of 25-hydroxyvitamin D had a greater mean global RNFL thickness in both eyes than in patients with insufficient levels of 25-hydroxyvitamin D; however the differences were not significant. Further research is necessary in order to determine whether or not there is a correlation between vitamin D and RNFL thickness and what role vitamin D plays in MS presentation.

No description available.

Retinal nerve fiber layer measurement in patients with Alzheimer's disease The current ophthalmologist's possibilities in diagnostics of Alzheimer's disease Alzheimer disease (AD) is the most common cause of dementia syndrome and mild cognitive impairment. To enroll the disease most securely there are used so called biomarkers using evidence of changed brain metabolism by pozitron emission tomography (PET) and in cerebrospinal fluid or the brain's structure magnetic resonance imaging (MRI). These methods are expensive, organisationally and temporally challenging and burdening for the patients. According to that reasons we are still seeking for alternative attitudes suitable for early diagnosis. The evaluation of thickness of retinal nerve fiber layer (RNFL) which is well accessible to examination through optical aparatus of the eye could be one of the options. The aim of our work was to present current knowledges about Alzheimer's disease targeting relations of Alzheimer's disease and an ophthalmological finding. In the next part of this paper we introduce the retinal nerve fiber layer measurement by optical coherence tomography (OCT) as a potential diagnostics method by screening of patients with Alzheimer's disease and to present our results measured in our cohort of patients. The studied cohort...

Abstract Glaucoma is a group of eye diseases characterized by a chronic, progressive optic neuropathy. During the disease process, the axon damage of the retinal ganglion cells leads to changes in the retinal nerve fiber layer, causing optic nerve head, and visual field defects typical of glaucoma. The Heidelberg Retina Tomograph (HRT) is a confocal scanning laser imaging device acquiring and analysing three-dimensional data of the ocular fundus wit good accuracy and reproducibility. Conventional planimetric measurements were compared to those taken with the HRT in a pilot study of 12 eyes with early glaucomatous optic disc, retinal nerve fiber layer and/or visual field abnormalities. The neuroretinal rim area measurements and cup-to-disc area ratio did not differ statistically from each other when using these two different methods. The effect of four different reference levels on the HRT parameter measurement values was tested in two separate studies. In the first study there were 67 eyes, 40 of the eyes were healthy and 27 eyes had glaucoma of different stages. Then, 279 eyes, 180 of which were non-glaucomatous and 99 glaucoma eyes, were included in another study. The flexible reference level gave the most reliable HRT parameter measurement values in both non-glaucomatous and glaucomatous eyes. The ability of the HRT parameters to separate between non-glaucomatous and glaucomatous eyes was tested in 77 eyes, 40 of the eyes were non-glaucomatous, 10 ocular hypertensives and 27 eyes had different stages of glaucoma. The reference level dependent HRT parameters cup-to-disc area ratio, vertical linear cup-to-disc ratio, mean retinal nerve fiber layer thickness (RNFLt) and rim volume as well as the reference level non-dependent HRT parameter, cup shape measure (CSM), separated best between the clinical groups. The best combination of the HRT and other structural and functional parameters in separating between non-glaucomatous and glaucomatous eyes was studied in 55 eyes. There were 32 non-glaucomatous eyes and 23 eyes with ocular hypertension or glaucoma. CSM, RNFLt, together with age- and lens coloration-corrected mean deviation of the B/Y perimetry showed good discrimination (ROC area 0.91) between non-glaucomatous and glaucomatous eyes. / Tiivistelmä Glaukooma koostuu joukosta hitaasti eteneviä näköhermon rappeumasairauksia. Sairausprosessin aikana verkkokalvon gangliosolujen aksonivaurio johtaa muutoksiin verkkokalvon hermosäiekerroksessa ja näköhermon päässä aiheuttaen glaukoomalle tyypillisiä näkökenttämuutoksia. The Heidelberg Retina Tomograph (HRT) on konfokaali laserskanneritekniikkaan perustuva kuvantamislaite, joka tuottaa ja analysoi silmänpohjasta saatua kolmiulotteista mittaustietoa tarkasti ja toistettavasti. Tavanomaisen planimetrian antamia mittaustuloksia verrattiin HRT:n antamiin tuloksiin 12:ssa silmässä, joissa oli todettu varhaisia glaukoomamuutoksia. Näköhermon pään hermoreunan (rim) pinta-ala ja keskuskuopan suhde papillan läpimittaan eivät poikenneet tilastollisesti toisistaan näitä kahta menetelmää käytettäessä. Neljän eri referenssitason vaikutusta HRT-parametrien mittausarvoihin testattiin kahdessa eri tutkimuksessa. Ensimmäisen tutkimusaineisto koostui yhteensä 67:stä silmästä, joista 40 oli terveitä ja 27:ssä eriasteisia glaukoomamuutoksia. Toisessa tutkimuksessa oli yhteensä 279 silmää, joista 180 oli terveitä ja 99:llä oli glaukooma. Papillomakulaarisäikeisiin tukeutuva, fleksiibeli referenssitaso antoi luotettavimmat HRT-parametrien mittaustulokset sekä terveissä että glaukoomasilmissä. HRT-parametrien kykyä erottaa terveet silmät glaukomatoottisista testattiin yhteensä 77:ssä silmässä, joista 40 oli terveitä, 10 oli korkeapaineisia ilman glaukoomamuutoksia, ja 27:ssä oli glaukoomamuutoksia. Referenssitasosta riippuvaiset HRT-parametrit, keskuskuopan suhde papillan läpimittaan, vertikaali-lineaarinen keskuskuopan suhde papillan läpimittaan, keskimääräinen verkkokalvon hermosäiekerroksen paksuus (RNFLt) ja `rim´:in tilavuus samoin kuin referenssitasosta riippumaton keskuskuopan ´vinous´-mitta (CSM) erottelivat parhaiten nämä kliiniset ryhmät toisistaan. Terveitä ja glaukoomasilmiä erottelevaa HRT:n ja muiden rakenteellisten ja toiminnallisten parametrien kombinaatiota etsittiin 55:n silmän aineistosta. Silmistä 32 oli terveitä ja 23 korkeapaineisia ja/tai glaukoomavaurioisia. CSM ja RNFLt, yhdessä iän ja mykiövärjäytymisen suhteen korjatun sinikeltaperimetrian keskipoikkeaman kanssa osoittivat hyvää erottelukykyä (ROC area 0.91) terveiden ja glaukoomasilmien välillä.

OBJETIVO: Investigar a correlação entre as espessuras da mácula e da camada de fibras nervosas da retina (CFNR), medidas pelas tomografias de coerência óptica de domínio Fourier (FD - OCT) e de domínio do tempo (TD - OCT) e a perda de sensibilidade no campo visual (CV) em pacientes com atrofia em banda do nervo óptico. Comparar a habilidade diagnóstica dos dois instrumentos. MÉTODOS: 36 olhos de 36 pacientes com perda de CV permanente por compressão do quiasma óptico e 36 controles normais foram submetidos ao exame de CV pela perimetria automatizada padrão (Humphrey Field Analyzer TM; Carl Zeiss Meditec, Dublin, CA), ao FD - OCT (3 D OCT-1000TM Topcon Corp., Tokyo, Japan) e ao TD - OCT (StratusTM ;Carl Zeiss Meditec Inc, Dublin, California, USA). Foram comparados os protocolos análogos de ambos os equipamentos para avaliação da espessura macular.Foi realizado a divisão macular em quatro quadrantes e em metades, sendo calculado a média da espessura macular global, a média da espessura dos quadrantes e a média da espessura das metades maculares. A média global e setorial da medida da espessura da CFNR peripapilar também foi analisada. A perda de sensibilidade no CV foi inicialmente avaliada pelo defeito temporal médio. O CV foi ainda dividido em 6 setores de acordo com a distribuição da CFNR e em 16 pontos centrais para a realização da correlação estrutura-função entre os parâmetros medidos pelo FD - OCT e a perda de sensibilidade no CV em decibéis e 1/Lambert. Foi calculado o coeficiente de correlação de Sperman e a análise de regressão linear. As áreas sobre a curva ROC e valores fixos de sensibilidade e especificidade foram calculados para cada parâmetro estudado. RESULTADOS: As medidas da espessura macular e da CFNR pelo FD - OCT e TD - OCT foram capazes de discriminar olhos com atrofia em banda do nervo óptico dos controles normais. A espessura global e setorial dos parâmetros maculares e da CFNR mostraram diferenças significativas (p<0,001) entre os doentes e os controles e os dois aparelhos tiveram desempenho semelhante na discriminação entre pacientes e controles. Em ambos existiram correlações significativas entre a perda de sensibilidade do CV e as medidas da espessura macular e da CFNR. As medidas de espessura nos quadrantes e nas metades nasais da macula, avaliadas pelo FD - OCT tiveram os melhores desempenhos nas correlações com os defeitos de CV, sendo o parâmetro com a melhor correlação, a medida do quadrante infero-nasal da mácula e a perda de sensibilidade do CV central do quadrante temporal superior central (r = 0.78, R2 = 61%, p<0,001). CONCLUSÕES: A espessura macular e a espessura da CFNR medidas pelo FD - OCT e pelo TD - OCT se correlacionaram topograficamente com a perda de sensibilidade no CV de pacientes com hemianopsia temporal por compressäo quiasmática. A correlação entre os quadrantes maculares e a perda de sensibilidade no CV, foram melhores do que aquelas entre o CV e as medidas da CFNR, principalmente nas medidas realizadas pelo FD - OCT. Este estudo demonstrou a importância clínica das medidas maculares na correlação estrutura-função e na quantificaçäo do dano neural em pacientes com compressão quiasmática, podendo ser útil na monitorização destes pacientes / PURPOSE: To investigate the relationship between fourier-domain optical coherence tomography (FD - OCT) measured macular and retinal nerve fiber layer thickness (RNFL) and visual field sensitivity loss on standard automated perimetry in eyes with permanent temporal hemianopia from chiasmal compression and compare the ability of FD - OCT and time-domain optical coherence tomography (TD - OCT) to detect axonal loss in eyes with band atrophy of the optic nerve. METHODS: One eye of each of 36 patients with permanent temporal visual field defects and 36 age- and sex-matched healthy subjects. Subjects underwent standard automated perimetry and macular and RNFL thickness measurements with FD - OCT (3 D OCT-1000® Topcon Corp., Tokyo, Japan) and TD - OCT (Stratus; Carl Zeiss Meditec Inc, Dublin, California, USA). Macular thickness measurements as a global average, divided in four quadrants and in two halves as well as average and sectoral RNFL thickness around the optic disc were calculated. Visual field sensitivity loss was evaluated by the temporal mean defect; as deviations from normal in six sectors of the visual field and in 16 central visual field test points. Relationship between visual field sensitivity loss in decibel and 1/Lambert units and optical coherence tomography measurements were evaluated using Spearman correlation coefficients and by linear regression analysis. Receiver operating characteristic curves and sensitivities at fixed specificities were calculated for each parameter. RESULTS: Global and sectoral macular and RNFL thickness parameters showed a significant difference in eyes with band atrophy compared with controls. The strongest correlations were seen between visual field sensitivity loss and quadrantic or hemianopic nasal macular thickness measurements than with sectoral retinal nerve fiber layer thickness measurements. The highest correlation was observed between the inferonasal quadrant macular thickness and the visual field sensitivity loss in the superior temporal central visual field quadrant (r = 0.78, R2 = 61%, p <0.001). CONCLUSION: Both RNFL thickness and macular thickness FD - OCT and TD - OCT measurements were related topographically with visual field sensitivity loss in patients with temporal hemianopia from chiasmal compression and there is a stronger relationship in quadrantic macular compared to RNFL thickness measurements with FD - OCT. Macular thickness measurements could potentially be used to quantify neuronal loss in patients with chiasmal compression and could prove clinically useful for detection of damage and for monitoring these patients

OBJETIVO: Investigar a correlação entre as espessuras da mácula e da camada de fibras nervosas da retina (CFNR), medidas pelas tomografias de coerência óptica de domínio Fourier (FD - OCT) e de domínio do tempo (TD - OCT) e a perda de sensibilidade no campo visual (CV) em pacientes com atrofia em banda do nervo óptico. Comparar a habilidade diagnóstica dos dois instrumentos. MÉTODOS: 36 olhos de 36 pacientes com perda de CV permanente por compressão do quiasma óptico e 36 controles normais foram submetidos ao exame de CV pela perimetria automatizada padrão (Humphrey Field Analyzer TM; Carl Zeiss Meditec, Dublin, CA), ao FD - OCT (3 D OCT-1000TM Topcon Corp., Tokyo, Japan) e ao TD - OCT (StratusTM ;Carl Zeiss Meditec Inc, Dublin, California, USA). Foram comparados os protocolos análogos de ambos os equipamentos para avaliação da espessura macular.Foi realizado a divisão macular em quatro quadrantes e em metades, sendo calculado a média da espessura macular global, a média da espessura dos quadrantes e a média da espessura das metades maculares. A média global e setorial da medida da espessura da CFNR peripapilar também foi analisada. A perda de sensibilidade no CV foi inicialmente avaliada pelo defeito temporal médio. O CV foi ainda dividido em 6 setores de acordo com a distribuição da CFNR e em 16 pontos centrais para a realização da correlação estrutura-função entre os parâmetros medidos pelo FD - OCT e a perda de sensibilidade no CV em decibéis e 1/Lambert. Foi calculado o coeficiente de correlação de Sperman e a análise de regressão linear. As áreas sobre a curva ROC e valores fixos de sensibilidade e especificidade foram calculados para cada parâmetro estudado. RESULTADOS: As medidas da espessura macular e da CFNR pelo FD - OCT e TD - OCT foram capazes de discriminar olhos com atrofia em banda do nervo óptico dos controles normais. A espessura global e setorial dos parâmetros maculares e da CFNR mostraram diferenças significativas (p<0,001) entre os doentes e os controles e os dois aparelhos tiveram desempenho semelhante na discriminação entre pacientes e controles. Em ambos existiram correlações significativas entre a perda de sensibilidade do CV e as medidas da espessura macular e da CFNR. As medidas de espessura nos quadrantes e nas metades nasais da macula, avaliadas pelo FD - OCT tiveram os melhores desempenhos nas correlações com os defeitos de CV, sendo o parâmetro com a melhor correlação, a medida do quadrante infero-nasal da mácula e a perda de sensibilidade do CV central do quadrante temporal superior central (r = 0.78, R2 = 61%, p<0,001). CONCLUSÕES: A espessura macular e a espessura da CFNR medidas pelo FD - OCT e pelo TD - OCT se correlacionaram topograficamente com a perda de sensibilidade no CV de pacientes com hemianopsia temporal por compressäo quiasmática. A correlação entre os quadrantes maculares e a perda de sensibilidade no CV, foram melhores do que aquelas entre o CV e as medidas da CFNR, principalmente nas medidas realizadas pelo FD - OCT. Este estudo demonstrou a importância clínica das medidas maculares na correlação estrutura-função e na quantificaçäo do dano neural em pacientes com compressão quiasmática, podendo ser útil na monitorização destes pacientes / PURPOSE: To investigate the relationship between fourier-domain optical coherence tomography (FD - OCT) measured macular and retinal nerve fiber layer thickness (RNFL) and visual field sensitivity loss on standard automated perimetry in eyes with permanent temporal hemianopia from chiasmal compression and compare the ability of FD - OCT and time-domain optical coherence tomography (TD - OCT) to detect axonal loss in eyes with band atrophy of the optic nerve. METHODS: One eye of each of 36 patients with permanent temporal visual field defects and 36 age- and sex-matched healthy subjects. Subjects underwent standard automated perimetry and macular and RNFL thickness measurements with FD - OCT (3 D OCT-1000® Topcon Corp., Tokyo, Japan) and TD - OCT (Stratus; Carl Zeiss Meditec Inc, Dublin, California, USA). Macular thickness measurements as a global average, divided in four quadrants and in two halves as well as average and sectoral RNFL thickness around the optic disc were calculated. Visual field sensitivity loss was evaluated by the temporal mean defect; as deviations from normal in six sectors of the visual field and in 16 central visual field test points. Relationship between visual field sensitivity loss in decibel and 1/Lambert units and optical coherence tomography measurements were evaluated using Spearman correlation coefficients and by linear regression analysis. Receiver operating characteristic curves and sensitivities at fixed specificities were calculated for each parameter. RESULTS: Global and sectoral macular and RNFL thickness parameters showed a significant difference in eyes with band atrophy compared with controls. The strongest correlations were seen between visual field sensitivity loss and quadrantic or hemianopic nasal macular thickness measurements than with sectoral retinal nerve fiber layer thickness measurements. The highest correlation was observed between the inferonasal quadrant macular thickness and the visual field sensitivity loss in the superior temporal central visual field quadrant (r = 0.78, R2 = 61%, p <0.001). CONCLUSION: Both RNFL thickness and macular thickness FD - OCT and TD - OCT measurements were related topographically with visual field sensitivity loss in patients with temporal hemianopia from chiasmal compression and there is a stronger relationship in quadrantic macular compared to RNFL thickness measurements with FD - OCT. Macular thickness measurements could potentially be used to quantify neuronal loss in patients with chiasmal compression and could prove clinically useful for detection of damage and for monitoring these patients

The master thesis is focused on creating a methodology for quantification of the nerve fiber layer on photographs of the retina. The introductory part of the text presents a medical motivation of the thesis and mentions several studies dealing with this issue. Furthermore, the work describes available textural features and compares their ability to quantify the thickness of the nerve fiber layer. Based on the described knowledge, the methodology to make different regression models enabling prediction of the retinal nerve fiber layer thickness was developed. Then, the methodology was tested on the available image dataset. The results showed, that the outputs of regression models achieve a high correlation between the predicted output and the retinal nerve fiber layer thickness measured by optical coherence tomography. The conclusion discusses an usability of the applied solution.