Browsing by Author "Cunha, JP"
Now showing 1 - 10 of 31
Results Per Page
Sort Options
- Alzheimer's Disease: a Review of its Visual System Neuropathology. Optical Coherence Tomography-a Potential Role As a Study Tool in VivoPublication . Cunha, JP; Moura-Coelho, N; Proença, R; Dias-Santos, A; Ferreira, J; Louro, C; Castanheira-Dinis, AAlzheimer's disease (AD) is a prevalent, long-term progressive degenerative disorder with great social impact. It is currently thought that, in addition to neurodegeneration, vascular changes also play a role in the pathophysiology of the disease. Visual symptoms are frequent and are an early clinical manifestation; a number of psychophysiologic changes occur in visual function, including visual field defects, abnormal contrast sensitivity, abnormalities in color vision, depth perception deficits, and motion detection abnormalities. These visual changes were initially believed to be solely due to neurodegeneration in the posterior visual pathway. However, evidence from pathology studies in both animal models of AD and humans has demonstrated that neurodegeneration also takes place in the anterior visual pathway, with involvement of the retinal ganglion cells' (RGCs) dendrites, somata, and axons in the optic nerve. These studies additionally showed that patients with AD have changes in retinal and choroidal microvasculature. Pathology findings have been corroborated in in-vivo assessment of the retina and optic nerve head (ONH), as well as the retinal and choroidal vasculature. Optical coherence tomography (OCT) in particular has shown great utility in the assessment of these changes, and it may become a useful tool for early detection and monitoring disease progression in AD. The authors make a review of the current understanding of retinal and choroidal pathological changes in patients with AD, with particular focus on in-vivo evidence of retinal and choroidal neurodegenerative and microvascular changes using OCT technology.
- Análise das Camadas Retinianas em Doentes com Lesão Isquémica da Artéria Cerebral Posterior Unilateral: um Estudo de Tomografia de Coerência ÓpticaPublication . Anjos, R; Cardigos, J; Costa, L; Borges, B; Alves, N; Amado, D; Ferreira, J; Cunha, JPIntrodução: A degeneração transneuronal retrógrada (DTR) das células ganglionares tem sido implicada na fisiopatologia de lesões na via visual posterior. Apesar de estarem descritas alterações nas camadas mais externas da retina na patologia do nervo óptico, esta relação com lesões a nível occipital permanece desconhecida. O objectivo do presente estudo é a avaliação das camadas nuclear interna (CNi), plexiforme externa (CPe), nuclear externa (CNe) e dos fotoreceptores (CFo) em doentes com lesões isquémicas da artéria cerebral posterior (ACP) com tomografia de coerência óptica (OCT). Métodos: Estudo transversal observacional, caso-controlo de doentes com hemianópsia homónima decorrente de lesão unilateral isquémica da ACP seguidos no departamento de Neuroftalmologia do Centro Hospitalar de Lisboa Central. Todos os doentes realizaram OCT macular em ambos os olhos. Após segmentação automática das diferentes camadas, foram obtidos os valores de espessuras correspondentes às regiões nasal e temporal entre 1 a 3mm (N1-3 e T1-3) e entre 3 e 6 mm (N3-6 e T3-6) centradas na fóvea. Resultados: Dez doentes com lesão da PCA e um grupo de controlo pareado para o sexo e idade foram incluidos no estudo. Quando comparados ambos os olhos do mesmo doente, verificou-se um aumento da espessura da CNi em N3-6 (p=0,005) do olho contralateral e em T3-6 (p=0,011) no olho ipsilateral, assim como da CPe em N3-6 (p=0,034) do olho contralateral. Não se verificaram diferenças estatisticamente significativas no grupo controle. Conclusão: Além da já documentada associação entre lesões isquémicas occipitais e as alterações nas camadas internas da retina, podemos ainda observar algumas alterações nas camadas retinianas mais externas. É possível que a DTR no sistema visual seja um processo que não se esgota nas células ganglionares, afectando camadas mais externas da retina.
- Células Endoteliais e Recuperação VisualPublication . Cunha, JP; Ferreira, JNa revisão bibliográfica encontramos perdas de céluas endoteliais que vão dos 4 aos 25%. Os vários estudos comparam EEC com e sem OVD, EEC e facoemulsificação, cataratas de diferente "dureza", entre outras variáveis. Também a idade, a ruptura do saco ou a perda de vítreo influenciavam estes resultados. As novas tecnologias para facoemulsificação como a peça de mão Ozil torsional que como o nome indica tem a capacidade de movimento torsional lateral (que desbasta a catarata além do movimento longitudinal da peça de mão convencional que emulsifica) torna os gestos cirúrgicos mais eficazes e seguros, reduzindo o traumatismo endotelial. Os AA fizeram um estudo prospectivo em que distribuíram 40 olhos de forma aleatória em dois grupos: 20 olhos foram operados por faco torsional e as restantes 20 cataratas foram operadas por faco convencional. Neste estudo comparativo entre faco torsional e convencional, o primeiro necessitou de menos ultrasons (0,048 versus 0,083), obteve uma acuidade visual média ligeiramente melhor (0,63 versus 0,54) e menor perda celular endotelial (3% versus 6,9%), no 1º dia de pós-operatório. Como se sabe, são múltiplos os factores que influenciam o resultado cirúrgico: o local e tamanho da incisão, a composição das soluções salinas, os dispositivos visco-elásticos, os produtos potencialmente tóxicos aplicados intra-operatoriamente, o tempo de cirurgia, a dureza da catarata, além das técnicas cirúrgicas e dos aparelhos utilizados.
- Choroidal Binarization Analysis: Clinical ApplicationPublication . Crisóstomo, S; Cardigos, J; Hipólito Fernandes, D; Luís, ME; Figueiredo, R; Moura-Coelho, N; Cunha, JP; Abegão Pinto, L; Tavares-Ferreira, JIntroduction: Image processing of optical coherence tomography scans through binarization techniques represent a non-invasive way to separately asses and measure choroidal components, in vivo. In this review, we systematically search the scientific literature regarding binarization studies published so far. Methods: A systematic research was conducted at PubMed database, including English literature articles for all of the following terms in various combinations: binarization, choroid/al, enhanced depth spectral domain/swept source optic coherence tomography, and latest publications up to November 2018 were reviewed. Results: Thirty-seven articles were included and analyzed regarding studied disease, binarization method, studied variables, and outcomes. Most of the studies have focused on the more common retinal pathologies, such as age-related macular degeneration, central serous chorioretinopathy and diabetic retinopathy but binarization techniques have also been applied to the study of choroidal characteristics in ocular inflammatory diseases, corneal dystrophies and in postsurgical follow-up. Advantages and disadvantages of binarization techniques are also discussed. Conclusion: Binarization of choroidal images seems to represent a promising approach to study choroid subcomponents in an increasingly detailed manner.
- Choroidal Thickness in Nonarteritic Anterior Ischaemic Optic Neuropathy: A Study with Optical Coherence TomographyPublication . Dias-Santos, A; Ferreira, J; Abegão Pinto, L; Vicente, A; Anjos, R; Cabugueira, A; Flores, R; Cunha, JPNonarteritic anterior ischemic optic neuropathy (NA-AION) is the most common nonglaucomatous optic neuropathy in adults over 50 years of age. It is usually related to cardiovascular risk factors. The primary objective of this study was to evaluate choroidal thickness in patients with chronic NA-AION, and the secondary objective was to evaluate macular thickness in these patients. This cross-sectional study compared two groups: group 1 included 20 eyes of 20 patients with chronic NA-AION, and group 2 included 31 eyes of 31 healthy controls. In both groups, the choroidal thickness was measured using the enhanced depth imaging program of Heidelberg Spectralis® optical coherence tomography (Heidelberg Engineering, Heidelberg, Germany). The macular thickness was also measured using the automatic software of the same device. The mean follow-up time after NA-AION in group 1 was 57.17 ± 26.92 months. The mean choroidal thickness of the posterior pole was 244.38 ± 61.03 µm in group 1 and 214.18 ± 65.97 µm in group 2 (p = 0.004). The mean macular thickness was higher in group 2. Macular thickness is reduced in eyes that had an episode of NA-AION, whereas choroidal thickness is generally higher in these eyes when compared with normal eyes. The increase in choroidal thickness may be due to a local dysfunction in vascular autoregulatory mechanisms, which may predispose to ischemic phenomena.
- Choroidal Thinning: Alzheimer's Disease and AgingPublication . Cunha, JP; Proença, R; Dias-Santos, A; Melancia, D; Almeida, R; Águas, H; Oliveira Santos, B; Alves, M; Ferreira, J; Papoila, AL; Louro, C; Castanheira-Dinis, AINTRODUCTION: The purpose of this study was to measure and to compare macular choroidal thickness (CT) between patients with mild Alzheimer's disease (AD), patients without AD, and elderly patients. METHODS: CT was measured manually in 13 locations at 500-μm intervals of a horizontal and a vertical section from the fovea. Linear regression models were used to analyze the data. RESULTS: Fifty patients with a diagnosis of mild AD (73.1 years), 152 patients without AD (71.03 years), and 50 elderly without AD (82.14 years) were included. In the AD patients, CT was significantly thinner in all 13 locations (P < .001-comparing with age-match group), and comparing with the elderly group, a more pronounced difference was found in two locations temporal to the fovea. DISCUSSION: Patients with AD showed a significant choroidal thinning even when compared with elderly subjects. The reduction of CT may aid in the diagnoses of AD, probably reflecting the importance of vascular factors in their pathogenesis.
- Diabetes Mellitus as a Risk Factor in Glaucoma's Physiopathology and Surgical Survival Time: A Literature ReviewPublication . Costa, L; Cunha, JP; Amado, D; Abegão Pinto, L; Ferreira, JGlaucoma is a multifactorial condition under serious influence of many risk factors. The role of diabetes mellitus (DM) in glaucoma etiology or progression remains inconclusive. Although, the diabetic patients have different healing mechanism comparing to the general population and it has a possible-negative role on surgical outcomes. This review article attempts to analyze the association of both diseases, glaucoma and DM, before and after the surgery. The epidemiological studies, based mainly in population prevalence analyzes, have shown opposite outcomes in time and even in the most recent articles also the association remains inconclusive. On the contrary, the experimental models based on animal induced chronic hyperglycemia have shown an important association of both diseases, explained by common neurodegenerative mechanisms. Diabetic patients have a different wound healing process in the eye viz-a-viz other organs. The healing process is more and it results in lower surgical survival time, higher intraocular pressure (IOP) levels and, therefore, these patients usually need more medication to lower the IOP. Both randomized and nonrandomized retrospective and experimental molecular studies have shown the association between DM and glaucoma. Further studies are needed to get better explanations about outcomes on more recent surgical procedures and with the exponential use of antifibrotics. How to cite this article: Costa L, Cunha JP, Amado D, Pinto LA, Ferreira J. Diabetes Mellitus as a Risk Factor in Glaucoma's Physiopathology and Surgical Survival Time: A Literature Review.
- Diabetic Choroidopathy: a Review of the Current LiteraturePublication . Melancia, D; Vicente, A; Cunha, JP; Abegão Pinto, L; Ferreira, JDiabetic retinopathy is an increasingly prevalent disease, and a leading contributor to the burden of all-cause blindness worldwide. In addition to retinal changes, choroidal abnormalities are common in patients with diabetes. The first studies concerning this vascular structure were based on histologic, indocyanine angiography and laser Doppler flowmetry techniques, but the development of new optical coherence tomography (OCT) technologies and imaging software for enhanced depth imaging (EDI)-OCT in recent years has made it possible to provide more detailed images of the choroidal anatomy and topography.In diabetic patients, several choroidal changes have been described in the literature throughout the years; the recent focus is choroidal thickness, which is significantly different from that in healthy patients. However, understanding choroidal manifestations of diabetic eye disease remains a real challenge, and this gap is hindering efforts towards better defining choroidal evaluation as a predictive factor for disease evolution and treatment response.This review aims to summarize the recent literature concerning changes in choroidal structure in diabetic patients, the relationship to diabetic retinal disease progression, and finally, the current and potential application of the measurement of variations in choroidal thickness for patient management.
- O Efeito de Pulfrich e a Esclerose MúltiplaPublication . Ferreira, J; Abegão Pinto, L; Amado, D; Cunha, JPIntrodução: O efeito de Pulfrich é um fenómeno psicofísico em que o movimento lateral/pendular de um objecto num plano bidimensional pode ser interpretado pelo córtex visual como um movimento tridimensional devido à diferença relativa do tempo de latência entre os dois olhos. Objectivo: Determinar se a neuropatia óptica desmielinizante unilateral ou assimétrica origina o fenómeno de Pulfrich. Métodos: Pesquisámos em 22 doentes com o diagnóstico de neuropatia óptica desmielinizante a percepção do fenómeno através de uma imagem pendular gerada por computador. Avaliámos as acuidades visuais corrigidas, realizámos Potenciais Evocados Visuais (PEV) para quantificação do tempo de latência da onda P100 e recorremos à interposição de um filtro polarizado de 70% para verificar a sua anulação. Resultados: Dez dos 22 doentes observaram o fenómeno e este foi abolido após interposição de um filtro polarizado. Conclusões: A neuropatia óptica pode originar o efeito de Pulfrich e explicar algumas queixas visuais aparentemente inespecíficas, sem alterações evidentes das acuidades visuais ou da estereopsia.
- Higher Order Aberrations in Amblyopic Children and their Role in Refractory AmblyopiaPublication . Dias-Santos, A; Rosa, R; Ferreira, J; Cunha, JP; Brito, C; Paixão, A; Toscano, AObjective: Some studies have hypothesized that an unfavourable higher order aberrometric profile could act as an amblyogenic mechanism and may be responsible for some amblyopic cases that are refractory to conventional treatment or cases of “idiopathic” amblyopia. This study compared the aberrometric profile in amblyopic children to that of children with normal visual development and compared the aberrometric profile in corrected amblyopic eyes and refractory amblyopic eyes with that of healthy eyes. Methods: Cross-sectional study with three groups of children – the CA group (22 eyes of 11 children with unilateral corrected amblyopia), the RA group (24 eyes of 13 children with unilateral refractory amblyopia) and the C group (28 eyes of 14 children with normal visual development). Higher order aberrations were evaluated using an OPD-Scan III (NIDEK). Comparisons of the aberrometric profile were made between these groups as well as between the amblyopic and healthy eyes within the CA and RA groups. Results: Higher order aberrations with greater impact in visual quality were not significantly higher in the CA and RA groups when compared with the C group. Moreover, there were no statistically significant differences in the higher order aberrometric profile between the amblyopic and healthy eyes within the CA and RA groups. Conclusions: Contrary to lower order aberrations (e.g., myopia, hyperopia, primary astigmatism), higher order aberrations do not seem to be involved in the etiopathogenesis of amblyopia. Therefore, these are likely not the cause of most cases of refractory amblyopia.