•Glaucoma is one of the most common and potentially severe ocular diseases.
It is one of the first causes of preventable blindness in western countries.
•Primary open-angle glaucoma (POAG): It is a chronic optic neuropathy of unknown origin,
characterized by a progressive loss of the axons of ganglional cells.
It is linked to an increase of the intra-ocular pressure (higher than 21 mmhg).
•Normal tension glaucoma (NTG): It is similar POAG but it is not related to an increase of intra-ocular pressure.
It is supposed that there are vascular factors that decrease the irrigation of the optic nerve head or a higher level of vulnerability of the optic nerve fibers at normal levels of intra-ocular pressure.
•Our study was designed to determine whether there are haemodynamic alterations of the retrobulbar arteries,
ophthalmic artery,
central retinal artery and short posterior temporal ciliary artery in glaucoma patients using Color and Spectral Doppler US.
- 354 eyes of 177 patients (1064 arteries) were analysed.
- 63 patients with primary open-angle glaucoma
- 22 patients with normal tension glaucoma
- 85 healthy control subjects
- None of the subjects of this study had a significant history of cardiovascular,
respiratory,
neurological or ophthalmological disease.
- Simple blind study: comparison of the control group with a glaucoma group.
- Patient lying face up,
head raised at an angle of approximately 30 degrees.
- Linear transducer set at 7.5 MHz.
- Transducer applied to the closed eyelid.
- No pressure applied on the eyeball during exploration.
Color and spectral Doppler US the ophthalmic artery,
central retinal artery and short posterior temporal ciliary artery:
- Identify the optic nerve in 2D.
- Adjust the colour box to the retrobulbar vessels,
focusing on the optic nerve.
- Position the viewfinder to measure the flow of the retrobulbar arteries.
Technical parameters:
- Adjust the focus to match the depth of the vessel under study.
- Filter: 70 Hz
- Pulse repetition frequency (PRF): 300 Hz
- Doppler angle: 0º - 60º
- Volume of sample: 1 - 3 mm.