Why indoor environments are hard on dry eyes

The tear film is constantly losing moisture to the surrounding air through evaporation. How quickly that evaporation occurs depends significantly on the humidity, temperature, and airflow of the environment you're in.

Most modern indoor environments — offices, cars, shopping centres, aeroplanes — have low humidity and active airflow from heating or cooling systems. This creates ideal conditions for rapid tear evaporation, destabilising the tear film and triggering or worsening dry eye symptoms.

Air conditioning

Air conditioning reduces temperature and — critically — reduces humidity. Low humidity accelerates tear film evaporation significantly. Air conditioning systems also circulate air, creating airflow across the ocular surface that further increases evaporation.

Patients who work in air-conditioned offices, drive for extended periods, or travel frequently by air often find their symptoms significantly worse in these environments — even when they're otherwise well controlled.

Practical steps

• Position yourself away from direct air conditioning vents where possible
• Use a desktop humidifier in your work environment — even a small increase in local humidity makes a meaningful difference
• Use preservative-free lubricating drops before prolonged exposure to air-conditioned environments rather than waiting until symptoms are already significant
• In cars, avoid directing air vents towards your face — particularly on long journeys

Central heating

Heating systems raise temperature and reduce relative humidity — warm air holds more moisture, so heating dry air reduces its relative humidity further. The result is a dry indoor atmosphere that accelerates tear evaporation, particularly in winter when heating is on for extended periods and windows are closed.

Practical steps

• A humidifier in rooms where you spend significant time — particularly the bedroom — can meaningfully improve overnight and morning eye comfort
• Avoid sitting directly next to radiators for extended periods
• Ventilating rooms briefly when possible helps maintain healthier humidity levels

Open plan offices

Open plan offices combine several problematic factors — air conditioning, screen use, low humidity, and often overhead lighting that increases glare and visual fatigue. Patients who work in open plan environments frequently find their dry eye symptoms are significantly worse on working days than at weekends.

If this pattern sounds familiar, it's worth discussing with us at your assessment — there are practical adaptations that can help.

Aeroplanes

Aircraft cabins are one of the most challenging environments for dry eyes. Cabin humidity is extremely low — typically 10 to 20 percent, compared to a comfortable indoor level of 40 to 60 percent. Combined with recycled air circulation and often several hours of screen use, flying can produce significant ocular surface dryness even in people without pre-existing dry eye.

Practical steps for flying

• Use preservative-free lubricating drops frequently throughout the flight
• Remove contact lenses before flying if possible — or use daily disposables and remove them during the flight
• Stay well hydrated with water rather than alcohol or caffeine
• Use a sleep mask if you sleep on the flight — it protects the ocular surface from airflow and reduces evaporation

Wind and outdoor environments

Cold wind is a significant trigger for dry eye symptoms — particularly in patients with an unstable tear film. Wind accelerates evaporation and stimulates reflex tearing that can paradoxically worsen symptoms.

Wraparound sunglasses provide meaningful protection in windy conditions — reducing airflow across the ocular surface and slowing evaporation. This is discussed further in our Sunglasses & UV Protection page.

The environment as an amplifier

Environmental factors rarely cause dry eye disease on their own. But in patients with underlying MGD or lid disease, a challenging environment tips a borderline tear film into symptomatic breakdown. Treating the underlying condition is what produces lasting improvement — but managing your environment sensibly reduces the daily symptom burden while treatment takes effect.

📍 Openshaw Opticians, Unit 4, 16 Cheapside, Cleckheaton, BD19 5AF 

📞 01274 878214