This paper reveals the important changes of fundus in healthy adults after exposure to high altitude, especially the changes of retinal vessels.

Changes in retinal thickness and fundus blood flow after prolonged high-altitude exposure, clarifying eye adaptation to hypoxic environments, lower pressure, more intense UV radiation, lower temperatures and dryer air.

The results of this paper not only reveal the changes of fundus after high altitude exposure, but also increase people’s attention to high altitude retinopathy. With the popularity of high-altitude sports, the incidence of high-altitude retinopathy may gradually increase.

To quantify the changes of long-term high altitude (HA) exposure of fundus in healthy adults. The aim is to provide a reference for the prevention and treatment of high altitude ophthalmopathy.

30 eyes of 15 healthy participants exposed to high altitude were recruited in this study. Swept-source optical coherence tomography/Swept-source optical coherence tomography angiography (SS-OCT/SS-OCTA) was used to analyze fundus changes in participants before and after plateau exposure. Fundus metrics included best corrected visual acuity (BCVA), the thickness of the retina (ReT), Inner ReT, Outer ReT, nerve fiber layer thickness (RNFLT), and ganglion cell internal plexiform layer thickness (GCIPLT), vascular density (VD), the size of the perfusion area (PA), choroidal vessel volume (CVV), and choroidal vascularity index (CVI) in all quadrants of the macula. All metrics were analyzed by generalized estimating equations (GEE).

Compared with baseline data, all participants who worked at high altitude for more than one year showed no change in visual acuity (P > 0.05) and a decreased in ReT, Outer ReT, GCIPLT and VD in all quadrants (P > 0.05). In addition, Inner ReT and RNFLT show an upward trend (P > 0.05). PA was significantly increased in the overall retina, Inner retina, superficial capillary plexus (SCP), and middle capillary plexus (ICP) (P < 0.05).

The systemic adaptive changes due to high altitude exposure may cause varying degrees of structural and functional changes in the fundus. The current findings require large-scale longitudinal studies to obtain more definitive data on this topic.

Optical coherence tomography-angiography

High altitude

Retinal thickness

Vessel flow density

Perfusion area

Fundus

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