Clinical trial NCT01802463: Study on Ocular Blood Flow and the Orbital Cerebrospinal Fluid Pressure in Glaucoma
Official title: Correlation Between Ocular Blood Flow and the Optic Nerve Sheath Diameter in Patients With Primary Open-angle Glaucoma
Study type: OBSERVATIONAL
Overall status: COMPLETED
Conditions: Open Angle Glaucoma
Normal Tension Glaucoma
Lead sponsor: Universitaire Ziekenhuizen KU Leuven
Sponsor class: OTHER
First posted: 2013-03-01
Enrollment: 197
Sex: ALL
Minimum age (years): 18
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: yes
Time perspective: PROSPECTIVE
Sampling method: PROBABILITY_SAMPLE
Study population: primary clinic care

Brief summary: Ocular blood flow has been consistently demonstrated to be altered in glaucoma patients when compared to otherwise healthy individuals. Numerous Doppler studies have shown a decrease in flow velocities in the retrobulbar arteries in what appears to be related to the degree of the glaucomatous disease.

The anatomic pathway of the several arteries into the eye is intricately complicate, with at least one of them (the central retina artery) penetrating the optic nerve before entering the eye and supplying the innermost structures of the globe. As the optic nerve is surrounded by a layer of cerebrospinal fluid (CSF) which is in continuity with the rest of the central nervous system, this central retinal artery has also to cross this CSF containing compartment. Because of the intrinsic pressure this CSF - corresponding to the intracranial pressure at the orbital level - the possibility exists that this pressure around the optic disc could affect the blood flow of the arteries that go through it.

The investigators will try to detect if a correlation exists between the optic nerve sheath diameter and the blood flow in the retrobulbar vessels of glaucoma patients.

Detailed description: 1. Visual field testing will be performed.
2. Structural analysis of the retinal nerve fiber layer (through confocal microscopy)will be performed.
3. Color Doppler Imaging of the retrobulbar vessels will be performed. Peak and end diastolic velocities, resistivity index will be calculated from the Doppler waveform.
4. B-scan ultrasound of the optic nerve sheath diameter will be performed. the measure will take place at 3mm behind the globe.

Eligibility criteria: 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

Primary outcomes:
measure: Flow velocity of retrobulbar vessels
timeFrame: Participants will be followed for the duration of hospital stay, an expected average of 2 hours
Secondary outcomes:
Other outcomes:
Locations:
city: Leuven
country: Belgium
facility: KU Leuven
state: Flemish Brabant
Study officials:
References:
citation: Willekens K, Abegao Pinto L, Vandewalle E, Marques-Neves C, Stalmans I. Higher optic nerve sheath diameters are associated with lower ocular blood flow velocities in glaucoma patients. Graefes Arch Clin Exp Ophthalmol. 2014 Mar;252(3):477-83. doi: 10.1007/s00417-013-2533-y. Epub 2013 Nov 27.