Journal of Clinical and Experimental Ophthalmology
Open Access
ISSN: 2155-9570
ISSN: 2155-9570
Sabrilhakim Sidek
Universiti Teknologi MARA, Malaysia
Posters & Accepted Abstracts: J Clin Exp Ophthalmol
Glaucoma is an irreversible and broadened theory of the progressive neurodegenerative disease of the visual pathway. Anatomical changes reflecting damage to the optic nerve (ON) head and retinal nerve fiber layer (RNFL) are the basis for glaucoma diagnosis and evaluation. Recent studies have broadened the theory of the neurodegenerative process of glaucoma beyond the ON per se to involve the entire visual pathway using assessment methods utilizing newer and more advanced MRI techniques. These include volumetric studies, diffusion tensor imaging (DTI) and spectroscopy imaging. Previous morphological studies evaluated the volume changes in various specific structures in the brain in patients with glaucoma using MRI. Automated, semi-automated or manual techniques are applied for volumetric measurement. DTI is used to measure the properties of water diffusion. The changes in these measurements reflect the changes in tissue microstructure. The DTI evaluates optic neuropathy by measuring the changes of fractional anisotropy (FA) and mean diffusivity (MD) values along the visual pathway. Assessment of FA provides information on the structural integrity of the fibre tracts while MD shows the average motion of water molecules, independent of fibre direction. Spectroscopy imaging enables detection, identification and quantification of metabolites such as N-acetyl aspartate (NAA), choline (Cho) and creatine (Cr) in the brain tissue. This approach provides physiological and chemical information. Alteration in metabolite concentration associated with many diseases such as neurodegenerative disease, brain hypoxia, tumors and stroke. Changes in metabolite concentrations in the visual pathway related to glaucoma disease have been previously published, and these studies demonstrated various findings.
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