What Happens to Your Eyes on a Long Flight?

By Alison Daoud, Australian Optometrist and Dermii Co-founder

Why plane cabins are so hard on your eyes

Cabin air is drawn from outside the aircraft at cruising altitude, where it's extremely cold and holds almost no moisture, then compressed and warmed before being circulated through the cabin. That process strips out most of the humidity the air originally had, which is why cabin humidity is so much lower than anywhere on the ground, including a dry heated room in winter.

Add several hours of continuous exposure, rather than the occasional dry patch you'd get walking between air-conditioned buildings, and the cumulative evaporative loss on your tear film is significant. Your eyes are working overtime to hold onto moisture in air that's actively taking it away, for as long as you're in the air.

The screen problem, twice over

Most flights now come with a personal entertainment screen built into the seat in front of you, and most passengers add a phone, tablet, or laptop on top of that. Screen-focused blink rate drops to around 5 to 7 blinks a minute compared to a normal 12 to 15, so hours of in-flight viewing compound the humidity problem rather than sitting alongside it.

It's the same mechanism that causes the afternoon slump at a desk, just intensified by cabin air and stretched over a much longer, uninterrupted stretch of time.

Why it's worse on long-haul than short domestic flights

A one-hour domestic hop rarely causes noticeable eye discomfort, because the exposure time is short. A ten or fourteen-hour long-haul flight is a different story. The evaporative loss and reduced blinking compound hour after hour with no real break, and most people don't think to interrupt their screen time or blink deliberately during a long flight the way they might during a long day at a desk.

By the time you land, many hours have passed with minimal blinking in the driest air you'll encounter all year, and the discomfort on arrival reflects that.

What most people do (and why it only helps a little)

Eye drops are the obvious go-to, and they do help in the moment, adding moisture back to a surface that badly needs it. The trouble is the same as anywhere else: drops address the water layer, not the oil layer that's supposed to be protecting it, so the relief is temporary, especially in air this dry.

Some travellers try to sleep through the flight to avoid the screen-time issue, which helps with blink rate but not with the humidity, since eyes are still exposed to the same dry air whether they're open or closed. Neither approach addresses the lid margin itself, which is where the longer-lasting fix actually sits.

Building a routine around your flight

The most effective approach treats the flight as three separate windows: before, during, and after. Before boarding, do your normal wipe and mist routine so your lid margin starts the flight clean rather than already carrying a day's build-up.

During the flight, on anything longer than a few hours, a mid-flight mist application takes seconds and supports the lid environment without needing water or a mirror. After landing, or during the flight if you're trying to sleep, the Self-Warming Eye Mask gives fifteen to twenty minutes of sustained warmth at the lid margin, which both helps release oil that's pooled in the glands and, for many people, doubles as a genuinely relaxing way to settle into sleep on a long flight.

A real example: using the mask to fall asleep in the air

One Dermii customer, Diana, uses the Self-Warming Eye Mask specifically on flights to help her fall asleep, alongside the comfort benefit for her eyes. It's a good illustration of why the mask earns its place in a travel bag beyond the obvious eye-comfort reason: gentle, sustained warmth over closed eyes is a genuinely calming sensation, and getting real rest during a long flight is itself one of the best things you can do for how your eyes, and the rest of you, feel on arrival.

What to pack

The individually wrapped Lid Love wipes travel well and don't need water, which makes the before-flight and after-landing steps easy in an airport bathroom or on the plane itself. The Miracle Mist's 30ml size clears standard carry-on liquid limits, so a mid-flight application is realistic without checking a bag. The Self-Warming Eye Mask needs no water, batteries, or microwave, just your own body heat and about fifteen minutes, which makes it one of the easiest genuinely comfort-boosting things to pack for a long flight.

The Lid Lover Starter Bundle covers all three steps in a travel-friendly format.

When to see your optometrist

If eye discomfort after flying is severe, doesn't ease within a day or two of landing, or comes with vision changes, real pain, or unusual redness, please see your eye care professional. Cabin air affects almost everyone to some degree, but persistent symptoms after you're back on the ground and rehydrated deserve a proper look.

Frequently asked questions