Premium
Hypoxia and retinal blood flow changes: a study using OCT‐Angiography
Author(s) -
Cordeiro Sousa D.,
Moreira S.,
Leal I.,
Dionísio P.,
Abegão Pinto L.,
MarquesNeves C.
Publication year - 2016
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.1755-3768.2016.0484
Subject(s) - medicine , hypoxia (environmental) , foveal , analysis of variance , population , retinal , blood flow , ophthalmology , repeated measures design , cardiology , oxygen , mathematics , chemistry , statistics , environmental health , organic chemistry
Purpose The raising number of commercial flights means a routinely exposure to hypoxic conditions by the crew and passengers. Aircrafts’ cabins are pressurized to a value of 565 mmHg, equivalent to breathing 15.1% oxygen at sea level. We aimed to study the relationship between normobaric hypoxia and retinal blood flow. Methods Prospective cohort study. The Hypoxia Challenge Test was performed at sea level, according to the British Thoracic Society protocol. OCT‐Angiography (AngioVue ® ) was done at three time‐points (baseline, hypoxia and 30’ post‐hypoxia). Foveal and parafoveal flow densities were assessed using built‐in AngioAnalytics ® . To guarantee data independence, right and left eyes were compared separately. Only images with high‐quality acquisition signal were included. Repeated‐measures ANOVA and mean comparison analysis were performed using STATA 13.0. Results Studied population included 30 subjects (14 women), with a mean age of 28.8 ± 4.2 [range 22–37] years. There was no statistically significant within‐subject difference in foveal flow density in both right and left eyes. However, within‐subject differences in parafoveal flow density were recognized for both right (p = 0.05) and left eyes (p = 0.03). Paired analysis confirmed a significant difference (p < 0.05) in mean parafoveal flow density between the three time‐points: baseline (OD = 55.7 ± 0.46, OS = 57.1 ± 0.44), hypoxia (OD = 56.7 ± 0.38; OS = 57.9 ± 0.35) and post‐hypoxia (OD = 56.1 ± 0.35, OS = 57.0 ± 0.39). Conclusions To our knowledge, there is no published data specifically addressing flight cabin hypoxia and eye hemodynamics. Our work in healthy subjects may help to establish normality thresholds and identify individuals at risk and their need for personalized screening and therapeutic air‐travel recommendations.