title: Correlation Between Peripapillary Choroidal Thickness and Retinal Vessel Oxygen Saturation in Young Healthy Individuals and Glaucoma Patients.
abstract: OBJECTIVE
  To investigate the correlation between peripapillary choroidal thickness (CT) and retinal vessel oxygen saturation (SO2) in young healthy individuals and open-angle glaucoma (OAG) patients.
  
  
  METHODS
  Fifty-four young healthy volunteers (aged 21.6 ± 1.1 years) and 48 OAG patients (aged 72.0 ± 9.1 years, visual field mean deviation -9.0 ± 8.1 dB) were included. Peripapillary CT was obtained using enhanced depth imaging optical coherence tomography (EDI-OCT). Arterial (SaO2) and venous (SvO2) retinal oxygen saturation were measured by a spectrophotometric retinal oximeter.
  
  
  RESULTS
  Arterial and SvO2 retinal oxygen saturation were significantly higher in the glaucoma group (95.1 ± 3.3% vs. 92.3 ± 3.0% and 60.8 ± 6.3% vs. 55.4 ± 4.6%, P < 0.001, respectively), while arteriovenous oxygen difference was significantly lower (34.4 ± 6.0% vs. 36.8 ± 3.8%, P = 0.014). Arterial and SvO2 retinal oxygen saturation were positively correlated with peripapillary CT in the healthy group (Spearman's ρ = 0.48, P < 0.001 and ρ = 0.41, P = 0.002, respectively), but not in the glaucoma group (P > 0.05). Multivariate analysis confirmed that these findings were independent of age, intraocular pressure, and mean arterial blood pressure and revealed a negative correlation between arteriovenous oxygen difference and CT in the healthy group (β = -0.337, P = 0.03).
  
  
  CONCLUSIONS
  In this study, we found a significant positive correlation between retinal vessel SO2 and peripapillary CT in young healthy individuals, but not in open-angle glaucoma patients. Further research is warranted to investigate whether the lack of correlation reflects a disturbance in the blood flow regulation in glaucoma patients. (ClinicalTrials.gov number, NCT01840202.).
authors.affiliation: Department of Ophthalmology University Hospitals Leuven, Leuven, Belgium.
authors.forename: Karel
authors.initials: K
authors.lastname: Van Keer
authors.affiliation: Department of Ophthalmology University Hospitals Leuven, Leuven, Belgium 2Department of Ophthalmology, Faculty of Medicine of Lisbon University, Lisbon, Portugal 3Visual Sciences Study Center, Faculty of Medicine of Lisbon University, Lisbon, Portugal.
authors.forename: Luís
authors.initials: L
authors.lastname: Abegão Pinto
authors.affiliation: Department of Ophthalmology University Hospitals Leuven, Leuven, Belgium.
authors.forename: Koen
authors.initials: K
authors.lastname: Willekens
authors.affiliation: Department of Ophthalmology University Hospitals Leuven, Leuven, Belgium 4Department of Ophthalmology Neurosciences, Laboratory of Ophthalmology, KU Leuven, Leuven, Belgium.
authors.forename: Ingeborg
authors.initials: I
authors.lastname: Stalmans
authors.affiliation: Department of Ophthalmology University Hospitals Leuven, Leuven, Belgium.
authors.forename: Evelien
authors.initials: E
authors.lastname: Vandewalle
mesh_terms: D000368:Aged; D002829:Choroid / Q000473:pathology*; D005260:Female; D005902:Glaucoma, Open-Angle / Q000097:blood* / Q000473:pathology*; D006801:Humans; D008297:Male; D010100:Oxygen / Q000097:blood*; D012171:Retinal Vessels; D041623:Tomography, Optical Coherence; D055815:Young Adult
chemical_list: D010100:Oxygen