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Hypoxia challenge test and retinal circulation changes – a study using ocular coherence tomography angiography
Author(s) -
Sousa David Cordeiro,
Leal Inês,
Moreira Susana,
Dionísio Patrícia,
Abegão Pinto Luís,
MarquesNeves Carlos
Publication year - 2018
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/aos.13622
Subject(s) - medicine , hypoxia (environmental) , retinal , ophthalmology , optical coherence tomography angiography , optical coherence tomography , population , angiography , repeated measures design , chemistry , statistics , mathematics , environmental health , organic chemistry , oxygen
Purpose Previous studies report that the response of retinal vessels to a decrease in oxygen (hypoxia) is vasodilation, thus increasing blood flow. We aimed to characterize the changes in retinal microvasculature induced by a mild hypoxia stress test in a healthy population, using ocular coherence tomography angiography ( OCT ‐A) technology. Methods Interventional repeated‐measures study. The standardized hypoxia challenge test ( HCT ) was performed to all volunteers, according to the British Thoracic Society protocol. Ocular coherence tomography angiography ( OCT ‐A) was performed at three time‐points (baseline, during HCT and 30′ posthypoxia). Macular and peripapillary vessel densities were assessed using the built‐in software. To minimize bias, analysis was performed separately in right ( OD ) and left ( OS ) eyes. Repeated‐measures anova and mean comparison analysis were used as statistical tests ( stata v13). Results Studied population included 30 healthy subjects (14 women), with a mean age of 28.8 ± 4.2 [range 22–37] years. Baseline vessel density increased in hypoxic conditions and subsequently decreased to near‐baseline values in posthypoxia conditions. This pattern was observed for both eyes in both parafovea ( OD : 55.3 ± 2.3 to 56.7 ± 1.9 to 55.8 ± 1.9, p < 0.05; OS : 56.9 ± 2.1 to 57.9 ± 1.9 to 57.3 ± 1.7, p < 0.05) and peripapillary ( OD : 60.5 ± 0.5 to 62.6 ± 0.5 to 60.1 ± 0.4, p < 0.05; OS : 60.4 ± 0.4 to 62.3 ± 0.5 to 60.7 ± 0.4, p < 0.05) areas. Conclusion To our knowledge, there are no published data specifically addressing mild hypoxia conditions and retinal microvasculature changes, using OCT ‐A. This pilot study may pave way to better understand vascular responses in disease setting.