Investigating Vitreous Oxygenation in CRVO & DR Using MRI - Pilot
Research type
Research Study
Full title
Investigating Vitreous Oxygenation in Central Retinal Vein Occlusion and Diabetic Retinopathy Using Magnetic Resonance Imaging - a Pilot Study
IRAS ID
129287
Contact name
Edward Hughes
Contact email
Sponsor organisation
Brighton & Sussex University Hospitals NHS Trust
Research summary
The vitreous gel fills the large space between the lens of the eye at the front and the retina at the back. The vitreous has no blood supply so its oxygen levels (pO2) are dependent on the metabolic state and blood flow to the retina, the underlying choroid and the ciliary body (which suspends the lens and makes intraocular fluid). Many retinal diseases are characterised by alterations in retinal blood flow and oxygenation, in particular the vascular diseases such as central retinal vein occlusion (CRVO) and diabetic retinopathy (DR). In other diseases such as the highly prevalent age-related macular degeneration (AMD), hypoxia (low oxygen levels) has also been aetiologically implicated.
Vitreous oxygenation is likely to be reduced in these retinal conditions, especially so in CRVO and DR, where clinically the eye is very ischaemic (low in oxygen). A few studies, in both humans and animals, have reported lower oxygen levels in the vitreous with these conditions, however these studies had to invasively insert probes into the eye, which in humans has had to be done at the time of surgery. The accuracy of these invasive techniques are limited, because in order to safely insert the probe into the eye, the vitreous cavity is infused with saline, which has an atmospheric level of oxygen (far higher levels). Also, the effect of simply making a small hole in the eye in order to insert the probe may increase vitreous oxygenation slightly, although this is not known.
MRI is a novel way of non-invasively measuring pO2 of body fluids in vivo. We have used this technique to successfully measure vitreous pO2 in non-ischaemic eyes (REC Ref: 10/H1111/52). We plan to use this same technique to now measure the vitreous pO2 in eyes with CRVO and DR.
REC name
London - Brighton & Sussex Research Ethics Committee
REC reference
13/LO/0959
Date of REC Opinion
11 Jul 2013
REC opinion
Favourable Opinion