BackgroundAutonomic neuropathy is a common and serious complication of diabetes. Early detection is essential to enable appropriate interventional therapy and management. Dynamic pupillometry has been proposed as a simpler and more sensitive tool to detect subclinical autonomic dysfunction. The aim of this study was to investigate pupil responsiveness in diabetic subjects with and without cardiovascular autonomic neuropathy (CAN) using dynamic pupillometry in two sets of experiments.MethodsDuring the first experiment, one flash was administered and the pupil response was recorded for 3 s. In the second experiment, 25 flashes at 1-s interval were administered and the pupil response was recorded for 30 s. Several time and pupil-iris radius-related parameters were computed from the acquired data. A total of 24 diabetic subjects (16 without and 8 with CAN) and 16 healthy volunteers took part in the study.ResultsOur results show that diabetic subjects with and without CAN have sympathetic and parasympathetic dysfunction, evidenced by diminished amplitude reflexes and significant smaller pupil radius. It suggests that pupillary autonomic dysfunction occurs before a more generalized involvement of the autonomic nervous system, and this could be used to detect early autonomic dysfunction.ConclusionsDynamic pupillometry provides a simple, inexpensive, and noninvasive tool to screen high-risk diabetic patients for diabetic autonomic neuropathy.

Autonomic neuropathy (AN) is a common and serious complication of diabetes. Early detection is essential to enable appropriate interventional therapy. It has long been recognized that subjects with diabetic peripheral neuropathy (DPN) are at much greater risk of developing AN, but there is currently no simple screening tool to assess them. The aim of this study was to investigate pupil responsiveness in diabetic subjects with and without DPN using dynamic pupillometry. During the first test, one flash was administered and the pupil response recorded for 3 seconds. In the second test, twenty-five flashes at one-second intervals were administered and the pupil response recorded for 30 seconds. Several time related parameters were computed from the results. A total of 29 diabetic subjects (17 no DPN, 12 DPN) and 25 healthy volunteers took part in the study. In the first test, pupil-iris ratios in darkness, large deviation and plateau were significantly different between groups. Latency time from flash exposure to the start of constriction was significantly longer in diabetic subjects with DPN compared to healthy volunteers. There was no difference in latency times of largest deviation, plateau or duration of constriction between groups. In the second test, the pupil-iris ratios evaluated in the frame preceding the tenth and the twenty-fifth light flash were significantly greater in healthy volunteers than diabetic subjects with DPN. Latency time from the tenth and twenty-fifth flash exposure to the start of constriction was significantly shorter in healthy volunteers than in diabetic subjects with DPN.

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Resumo-Técnicas de identificação automática de indivíduos baseadas em características biométricas facilitam o controlede sistemas de segurança, além de reduzir o risco de falhas. Utilizando processamento de imagens capturadas à distância, métodos de reconhecimento facial ou por íris apresentam a vantagem de utilizar processos não invasivos. Ao mesmo tempo, os algoritmos mais usados nestas áreas baseiam-se apenas em características estáticas, o que facilita a ocorrência de fraudes. O uso de reflexos humanos para identificação impede a cópia de características, uma vez que são respostas dinâmicas involuntárias, além de garantir que a pessoa fisicamente presente apresenta sinal de vida. Este artigo mostra um estudo preliminar sobre a possibilidade de utilização de pupilometria dinâmica, isto é, da medição da variação do raio da pupila, para a identificação de indivíduos através do reflexo pupilar.Palavras-chave-Biometria, pupilometria, processamento de imagens.Abstract-Techniques for automatic personal identification based on biometric features enhance the control of security systems, and reduce failure risks. By processing images captured from a distance, facial and iris recognition methods have the advantage of using non-invasive procedures. Nevertheless, most of the algorithms applied in these areas are based only on static features, facilitating the occurrence of frauds. The use of human reflex for identification prevents features copy, since the dynamic responses are involuntary, ensuring at the same time that the person being tested is alive. This paper presents a preliminary study of the use of dynamic pupillometry, which means the measure of pupil radius variation, for biometric personal identification through the pupillary reflex.Keywords-Biometrics, pupillometry, image processing. IntroduçãoA identificação pessoal é hoje essencial para a garantia da segurança física e de informações. Geralmente, a confirmação da identidade é feita através de reconhecimento humano, verificação de documentos, senhas, chaves e códigos de acesso. Mais recentemente, diversas técnicas de reconhecimento automático baseadas em informações biométricas tem sido desenvolvidas com o objetivo de impedir fraudes, erros humanos, cópias, compartilhamentos, esquecimentos e perdas.Estes métodos baseiam-se em características pessoais fisiológicas, relacionadas apenas com atributos físicos do corpo, ou comportamentais, analisando ações, movimentos ou outras informações dinâmicas da pessoa. Alguns exemplos de sistemas biométricos são: análise da impressão digital, assinaturas manuscritas, forma da mão, voz. No entanto, tais sistemas requerem a cooperação da pessoa através do contato físico ou pela execução de uma ação específica, abrindo espaço para falhas devido ao comportamento (Wildes, 1997).Uma forma de se evitar este tipo de problema é através do processamento de imagens capturadas a distância. Para o reconhecimento facial, por exemplo, não é necessário o contato da pessoa com nenhum aparelho. Entretanto, há muitas dificuldades nesta téc...