Measurement of PO2 during vitrectomy for central retinal vein occlusion, a pilot study

Williamson, Tom H.; Grewal, Jas; Gupta, Bhaskar; Mokete, Bataung; Lim, M.; Fry, Christopher

doi:10.1007/s00417-009-1072-z

Cited by 60 publications

(57 citation statements)

References 30 publications

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“…36 Studies in human eyes have been restricted to measurements of vitreous pO 2 during intraocular surgery. [37][38][39] The potential value of the clinical measurement, but the invasive nature of the techniques described above, have ensured that non-invasive retinal vessel oximetry in humans remains an important aspiration. This report describes the design of a retinal camera, which has allowed successful acquisition of spectal images of the retina, and details the image processing and analysis techniques, which have been used to calculate the OS of the retinal vasculature in a small group of normal subjects and in an illustrative example of a patient with a branch retinal arterial occlusion.…”

Section: Discussionmentioning

confidence: 99%

Spectral imaging of the retina

Mordant

Alabboud

Muyo

et al. 2011

Eye

102

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Introduction The work described here involved the use of a modified fundus camera to obtain sequential hyperspectral images of the retina in 14 normal volunteers and in 1 illustrative patient with a retinal vascular occlusion. Methods The paper describes analysis techniques, which allow oximetry within retinal vessels; these results are presented as retinal oximetry maps. Results Using spectral images, with wavelengths between 556 and 650 nm, the mean oxygen saturation (OS) value in temporal retinal arterioles in normal volunteers was 104.3 ( ± 16.7), and in normal temporal retinal venules was 34.8 (±17.8). These values are comparable to those quoted in the literature, although, the venular saturations are slightly lower than those values found by other authors; explanations are offered for these differences. Discussion The described imaging and analysis techniques produce a clinically useful map of retinal oximetric values. The results from normal volunteers and from one illustrative patient are presented. Further developments, including the recent development of a 'snapshot' spectral camera, promises enhanced non-invasive retinal vessel oximetry mapping.

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Section: Discussionmentioning

confidence: 99%

Spectral imaging of the retina

Mordant

Alabboud

Muyo

et al. 2011

Eye

102

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“…Invasive oxygen electrodes or fiberoptic probes reported vitreous Po 2 of 7-34 mm Hg (1,3,4,14) in patients during ocular surgery and 13-36 mm Hg in anesthetized healthy rats, rabbits, and cats (14-17) compared with midvitreous Po 2 of 18.3 mm Hg measured with MR imaging in this study. …”

Section: Discussionmentioning

confidence: 52%

“…Oxygen tension (in millimeters of mercury) in phantoms was measured by using an oxygen-sensitive fiberoptic probe (OxyLab; Oxford Q uantitative measurement of Po 2 in vivo could provide a clinically relevant indicator of oxygen concentration in the vitreous and the surrounding tissue, such as the retina, lens, and ciliary body. Abnormal vitreal oxygen tension has been linked to a number of ocular diseases, including cataract, diabetic retinopathy, and central retinal vein occlusion (1)(2)(3)(4). Vitrectomy (1,5) and hyperbaric oxygen therapy (6) have been associated with increased incidence of nuclear cataract, likely related to high vitreal Po 2 and reactive oxygen species contributing to cataract formation (7).…”

Section: Phantom and Ex Vivo Studiesmentioning

confidence: 99%

“…In patients undergoing ocular surgery, midvitreous Po 2 was lower than near the retina (14) and the anterior vitreous (1,14). However, there are reports of lower vitreal Po 2 near the retina than other regions (4,18). These reported regional differences in the human eye are generally small (,4 mm Hg) (1,3,14,18), and different diseases might have different effects on the spatial distribution of Po 2 (3,18).…”

mentioning

confidence: 97%

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Human Vitreous: MR Imaging of Oxygen Partial Pressure

Muir¹,

Zhang²,

Nateras³

et al. 2013

Radiology

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Purpose:To develop a magnetic resonance (MR) imaging approach to noninvasively image quantitative Po 2 in the human vitreous. Materials and Methods:Human studies were approved by the institutional review board with informed consent obtained from all subjects and were HIPAA compliant. Animal studies were performed with animal care committee approval. An MR imaging method to measure the longitudinal relaxation rate, or R1, of water was implemented with a 3.0-T MR imager. R1 was calibrated in water phantoms at multiple Po 2 and temperature conditions (n = 10) and in ex vivo animal vitreous (n = 2). Vitreous Po 2 was imaged in three human volunteers (age range, 26-28 years) in multiple sessions on separate days to evaluate reproducibility. The effects of temperature and ambient air were evaluated by acquiring data with the eye open and closed. Statistical analysis consisted of t tests, with P less than .05 indicating significant difference.

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“…Whether such improvement was entirely attributable to the removal of traction remained questionable. Williamson et al measured the pO2 and demonstrated an increase after vitrectomy in patients with retinal vein occlusion [9] .…”

mentioning

confidence: 99%