Intraocular gas tamponade, widely used in vitreoretinal surgery, can pose risks during air travel and high-altitude mountain trips. Low atmospheric pressure can increase intraocular pressure when the eye’s volume capacity is exceeded, potentially leading to acute glaucoma or central retinal artery occlusion. While the public is generally aware of avoiding air travel with intraocular gas, the dangers of high-altitude travel are less recognized. Here, we describe a case of severe retinal circulation occlusion following high-altitude travel in a patient with intraocular gas tamponade. This case underscores the importance of informing patients with intraocular gas tamponade to avoid high-altitude travel.
A 65-year-old male presented to our emergency department with pain and vision loss in his right eye following a mountain trip to an elevation of 7085 feet above sea level (ASL). He reported no history of systemic disease. Three weeks prior to the mountain trip, he had undergone a vitrectomy with a 15 % perfluoropropane (C3F8) gas tamponade in the right eye for inferior rhegmatogenous retinal detachment ( Fig. 1 A). The trip began at 200 feet ASL, and he ascended to 5415 feet ASL within one hour without experiencing any discomfort. However, as he ascended, he developed a right forehead ache and a feeling of fullness in his right eye. Upon reaching 7085 feet ASL half an hour later, the discomfort worsened. After spending 1.5 h at 7085 feet, he experienced extreme discomfort and vomiting, prompting him to descend. The discomfort resolved upon returning to flat ground, but he noticed complete vision loss in his right eye.
Examination revealed only light perception in the right eye, with an intraocular pressure (IOP) of 10.5 mm Hg. The retina was whitening but remained reattached with 70 % gas still present ( Fig. 1 B). One month after the event, fundus photography and fluorescein angiography showed a pale optic disc, severely attenuated retinal vessels, and diffuse retinal pigment epithelial changes ( Fig. 1 C, D). Oculoplethysmography indicated relatively reduced blood flow in the right ophthalmic artery. Doppler echocardiography was normal, and carotid Doppler revealed only 7 % stenosis in the left common carotid artery. The patient was treated with oral pentoxifylline 400 mg twice daily, but visual acuity remained at no light perception over four months of follow-up.
Intraocular gas tamponade is commonly used in modern vitreoretinal surgery; both air travel and high-altitude mountain trips expose patients with gas-filled eyes to low atmospheric pressure. Once the volume of the globe reaches its maximum capacity, IOP rises, potentially causing acute glaucoma or central retinal artery occlusion. While the public is generally aware of the need to avoid air travel when intraocular gas is present, the risks associated with high-altitude mountain travel are less recognized.
Several studies have examined the rise of IOP in gas-filled eyes during air travel. However, mountain travel involves a slower ascent rate, giving the eye more time to adjust to intraocular gas expansion, resulting in less IOP elevation under similar pressure changes. In contrast, cabin pressure drops from 760 to 564 mm Hg on a commercial flight within about 10 min after takeoff, equivalent to the pressure at 8000 feet ASL. This rapid change can lead to a more significant IOP increase than the gradual ascent experienced during mountain travel. The volume of intraocular gas may also impact the extent of IOP increase during altitude changes. Previous studies have indicated that intraocular gas volumes of less than 10 % may be safe for high-altitude travel in human eyes. However, the safe volume of intraocular gas for high-altitude travel remains a topic of debate.
Furthermore, at high altitudes, the partial oxygen pressure decreases along with atmospheric pressure. According to a previous study, at an altitude of 8000 ft ASL, the partial oxygen pressure drops from 159 mm Hg to 118 mm Hg. In a gas tamponade eye, this reduction in oxygen pressure, combined with elevated IOP, may compromise arterial circulation, potentially leading to retinal hypoxia. Additionally, the decreased partial oxygen pressure can lower the oxygen saturation in the retinal artery, further exacerbating the retina’s hypoxic condition and increasing the risk of retinal damage due to ischemia and hypoxia.
In conclusion, Intraocular gas tamponade with either sulfur hexafluoride (SF6) or perfluoropropane (C3F8) is commonly used in modern vitreoretinal surgery to manage various ocular conditions, such as retinal detachment, diabetic retinopathy, and macular disorders. Given the growing number of patients undergoing vitreoretinal surgery and the increasing popularity of high-altitude travel, the dangers of high-altitude travel should also be carefully considered.
Consent for publication
Written informed consent was obtained from the patient for publication of this case report and any accompanying images.
Financial Support
None.
Additional Contributions
We thank the patient for providing permission to share his information.
Conflict of interest
No author has any conflicts of interest to declare.
References
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