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Measurement of the pulsatile ocular dynamics of the human eye for glaucoma diagnosis.


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Singh, Kanwarpal (2012). Measurement of the pulsatile ocular dynamics of the human eye for glaucoma diagnosis. Thèse. Québec, Université du Québec, Institut national de la recherche scientifique, Doctorat en sciences de l'énergie et des matériaux, 131 p.

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The objective of this thesis work is to design a non-invasive diagnostic instrument to study the biomechanical properties of the eye and test the potential of this instrument for the early diagnosis of glaucoma. G1aucoma is an eye disease in which the vision loss is permanent. The present diagnostic methods are unable to detect glaucoma in its initial stages. It commonly takes several years following the onset of the disease in order to identify people with glaucoma. A new diagnostic instrument that could detect glaucoma at its onset is highly desirable. It has been shown in numerous studies that pulsatile ocular blood flow plays a major role in glaucoma. The ocular blood flow drives the mechanical pulsations of the eye. As both ocular blood flow and ocular biomechanics are altered in glaucoma, it can be assumed that the mechanical pulsations driven by ocular blood flow would also be altered. A device capable of measuring such pulsations could potentially be used as a new diagnostic tool for glaucoma. In previous works, the pulsatility of the eye has been measured using tonometer-based technologies, which measure the variations in the intra ocular pressure at the cornea. These instruments do not measure mechanical displacement of ocular tissues. Furthermore, most of the tonometer-based technologies have to make contact with the eye in order to perform such measurements. As contact techniques are not preferred for the reasons such as infection and damage to the eye, technologies that require no contact with the eye were sought. Technologies such as ultrasonic transducers, laser interferometry and low-coherence interferometry have been used to measure one or the other aspect of the ocular pulsations. Ultrasonic transducers were shown to measure the corneal axial displacements, but could not be applied to measure the pulsations of the interior ocular tissues, such as the retina. In glaucoma it could be more interesting to measure the pulsatility of the retina rather than that of the cornea. Therefore technologies such as laser interferometry and low coherence interferometry have been applied by sorne research groups. In this thesis work, a device based on Fourier-domain low-coherence interferometry was developed. The device was first tested on live animals, such as rabbits and rats, and then further tested on human subjects recruited at the Research Center of the Hospital Maisonneuve-Rosemont. The developed device could measure simultaneously the pulsations of the comea and the retina. In the later part of the thesis work, a comparative study between glaucoma and nonglaucoma subject was performed. The results obtained suggest that the pulsations of the ocular tissues, such as the comea and the retina, are larger in patients with glaucoma compared to normal subjects. The developed device provides for the first time an opportunity to study the pulsations of the comea and the retina simultaneously and at video rate, with a displacement resolution as small as 400 nm. This allows the researchers and the clinicians to measure the biomechanical properties of the eye and study their role in glaucoma.

Type de document: Thèse Thèse
Directeur de mémoire/thèse: Ozaki, Tsuneyuki
Co-directeurs de mémoire/thèse: Lesk, Market Costantino, Santiago
Mots-clés libres: tissus; oculaires; lame; criblée; glaucome; interférométrie;IFC-DS
Centre: Centre Énergie Matériaux Télécommunications
Date de dépôt: 22 janv. 2013 16:39
Dernière modification: 03 févr. 2021 16:03
URI: https://espace.inrs.ca/id/eprint/710

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