Glaucoma is a leading cause of blindness worldwide, whose treatment - intraocular pressure lowering - is only partially effective in preventing disease progression. Accordingly, other variables, such as ocular blood flow-related factors, have been implicated in disease pathogenesis. However, most findings involving vascular variables come from partial, small-scale studies. Furthermore, recent technological advances have identified a number of ocular blood flow variables that have yet to be tested in large scale trials. Therefore, a study that specifically aims at uncovering the role of vascular aspects in glaucoma is needed.

For this purpose, a cross-sectional, observational case-control study will be conducted in the University Hospitals Leuven. This will be the largest-yet study on the subject, involving more than 750 patients. This will allow the creation of a specific cohort of patients where the vascular aspects are thought to be particularly important (low-tension glaucoma). It will use the largest combination yet of vascular-related measuring techniques (dynamic contour tonometry, optic coherent tomography, colour Doppler imaging and retinal oximetry)

1. Demographic and clinical ophthalmology-related examination data will be collected, including intraocular pressure measurement using dynamic contour tonometry
2. Visual field testing will be performed.
3. Structural damage will be documented by a retinal nerve fiber layer analysis (through Heidelberg Retinal Tomograph)
4. High Definition Optical coherent tomograph imaging of the submacular and peripapillary choroidal thickness will be performed.
5. Color Doppler Imaging of the retrobulbar vessels will be performed, with analysis of the Doppler waveform (peak systolic, end diastolic velocities and resistivity index)
6. Retinal oximetry will be performed with the analysis of the arterial and venous saturations of retinal vessels

Inclusion Criteria:

• individuals over 18 years old
• willing to sign an informed consent and able to comply with the requirements of the study
• having no other ocular diseases besides glaucoma

Exclusion Criteria:

• history of ocular trauma
• intraocular surgery (except for cataract surgery)
• eye disease (except glaucoma)
• systemic diseases with ocular involvement like diabetes

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