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Oximetry in glaucoma: correlation of metabolic changes with structural and functional
Author(s) -
VANDEWALLE E,
PINTO LA,
OLAFSDOTTIR OB,
STALMANS P,
VAN CALSTER J,
ZEYEN T,
STEFANSSON E,
STALMANS I
Publication year - 2012
Publication title -
acta ophthalmologica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.534
H-Index - 87
eISSN - 1755-3768
pISSN - 1755-375X
DOI - 10.1111/j.1755-3768.2012.4651.x
Subject(s) - retinal , ophthalmology , glaucoma , oxygen saturation , visual field , medicine , nerve fiber layer , oxygen , saturation (graph theory) , chemistry , mathematics , organic chemistry , combinatorics
Abstract Purpose To determine whether retinal vessel oxygen saturation in glaucoma patients is associated with structural optic disc and retinal nerve fiber layer (RNFL) changes and visual field defects. Methods Retinal oxygen saturation was measured in glaucoma patients with a non‐invasive retinal oximeter (Oxymap ehf, Reykjavik, Iceland). Visuals fields and HRTs were performed on the same day. Statistical analysis was performed using Student’s t‐test and Pearson correlation coefficient when the data were normally distributed: otherwise Spearman correlation was used. Results The mean oxygen saturation in the arterioles was 97% ± 2%, in venules 65% ± 6% and the arteriovenous (AV) difference was 33% ± 6%. The oxygen saturation in the venules correlated with the visual field mean defects (r= ‐0.42; p=0.001; n=59) as well as with the structural HRT parameters rim area and RNFL (r= ‐0.39; p=0.008 and r= ‐0.26; p= 0.05 respectively; n=53). The AV difference decreased significantly as the visual field defect worsened (r= 0.38; p=0.003), as the rim area diminished (r= 0.29; p=0.03) and as the RNFL decreased (r= 0.27; p= 0.05). No correlation was found between the oxygen saturation in the retinal arterioles and either of these parameters. Conclusion Severe glaucomatous damage is associated with increased oxygen saturation in retinal venules and decreased AV difference in oxygen saturation. These data suggest that in eyes with severe glaucomatous damage, retinal oxygen consumption is decreased due to tissue loss.