title: Attenuation of S-cone function at high altitude assessed by electroretinography.
abstract: As impaired S-cone function has been reported psychophysically this study assessed S-cone function during high altitude exposure using electroretinography (ERG) and investigated a possible association with severity of acute mountain sickness (AMS). This work is related to the Tübingen High Altitude Ophthalmology (THAO) study. Standard ERG equipment was used (Diagnosys LLC, Cambridge, UK) with special protocol settings to extract S-cone function. Twelve subjects were analyzed in the current study and examinations were performed in Tübingen, Germany (341m) as baseline and thereafter at the Capanna Margherita, Italy (4559m) at high altitude. Results were compared using a paired t-test. Correlations between ERG measurements and oxygen saturation (SpO2), heart rate (HR) and scores of acute mountain sickness (AMS-C and LL) were calculated using Pearson's correlation coefficients. Amplitudes of S-cone b-waves decreased significantly at high altitude (p=0.02). No significant changes were observed for implicit times of b-waves (p=0.63), a-waves (p=0.75) or for a-wave amplitudes (p=0.78). The incidence of AMS was 50% at high altitude according to AMS-C and LL scores (AMS-C⩾0.7 and LL⩾5). Heart rate increased to 84±10min(-1) and SpO2 decreased to 71.9±5.7% at high altitude. No significant correlation was found between S-cone ERG parameters and SpO2, HR, AMS-C and LL. For the first time our study defines a significant impairment of S-cone function at high altitude time using objective state of the art examination methods. No correlation between the functional impairment of S-cones and levels of AMS was detected.
authors.affiliation: Centre for Ophthalmology, University of Tübingen, Tübingen, Germany; Department of Ophthalmology, Katharinenhospital Stuttgart, Stuttgart, Germany. Electronic address: andreas.schatz@med.uni-tuebingen.de.
authors.forename: Andreas
authors.initials: A
authors.lastname: Schatz
authors.affiliation: Centre for Ophthalmology, University of Tübingen, Tübingen, Germany; Nuffield Laboratory of Ophthalmology Oxford, University of Oxford, Oxford, United Kingdom.
authors.forename: M
authors.initials: M
authors.lastname: Dominik Fischer
authors.affiliation: Department of Sports Medicine, Medical Clinic, University Hospital Heidelberg, Heidelberg, Germany.
authors.forename: Kai
authors.initials: K
authors.lastname: Schommer
authors.affiliation: Centre for Ophthalmology, University of Tübingen, Tübingen, Germany.
authors.forename: Eberhart
authors.initials: E
authors.lastname: Zrenner
authors.affiliation: Centre for Ophthalmology, University of Tübingen, Tübingen, Germany.
authors.forename: Karl-Ulrich
authors.initials: KU
authors.lastname: Bartz-Schmidt
authors.affiliation: Centre for Ophthalmology, University of Tübingen, Tübingen, Germany; Department of Ophthalmology, Katharinenhospital Stuttgart, Stuttgart, Germany.
authors.forename: Florian
authors.initials: F
authors.lastname: Gekeler
authors.affiliation: Centre for Ophthalmology, University of Tübingen, Tübingen, Germany; Department of Ophthalmology, Katharinenhospital Stuttgart, Stuttgart, Germany.
authors.forename: Gabriel
authors.initials: G
authors.lastname: Willmann
mesh_terms: D000328:Adult; D000531:Altitude; D000532:Altitude Sickness / Q000503:physiopathology*; D003118:Color Perception / Q000502:physiology*; D004596:Electroretinography; D005260:Female; D006801:Humans; D000860:Hypoxia / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D017949:Retinal Cone Photoreceptor Cells / Q000502:physiology*
keywords: Electroretinography; High altitude; Hypobaric hypoxia; Hypoxia; Retinal function