Over 4 billion airplane journeys were made in 2018 [1], many by passengers who regularly wear contact lenses or commonly apply eyedrops for the treatment of glaucoma or management of dry eye disease. Dry eye, a multifactorial disorder of the ocular surface stemming from a loss of homeostasis of the tear film and leading to inflammation, ocular irritation, mucosal dryness, and foreign body sensation [2, 3], is exacerbated in contact-lens wearers, and particularly in low relative humidity environments such as airplane cabins [4]. In-flight cabins present a unique challenge to patients in need of frequent eye lubrication, as high-altitude air is dehydrated upon passing through the airplane’s turbine [5]. In addition to low humidity within the cabin, barometric pressure is also reduced to increase airflow during flight [5]. The combination of these environmental factors poses an interesting scenario for frequent fliers and ophthalmologists alike.

Recognizing the variability in eyedrop bottles on the market, our objective was to conduct an in-flight experiment to assess the functionality and drop release of six brands of artificial tears: Lacrifilm® (0.5% carmellose sodium—Genom); Optive® (carmellose sodium, glycerol, sodium hyalunorate—Allergan); Hyabak® (0.15% sodium hyaluronate—Laboratoire Théa); Lacrilax® (0.5% carmellose sodium—Cosmed); Systane® UL (hydroxypropyl guar 8A, polyethylene glycol 400—Alcon); and Hylo Comod® (0.1% sodium hyaluronate—Ursapharm). Five unopened bottles of each brand were opened on land as a control; their performance was assessed at a cruising altitude of 10,000 feet during a national flight and again at an altitude of 35,000 feet during an international flight.

Log in or create a free account to read this content

Gain free access to this article, as well as selected content from this journal and more on nature.com

Access through your institution

or

Sign in or create an account
Continue with Google
Continue with ORCiD