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Dry eyes, redness and discomfort may be more than just a nuisance during bushfire season, with new research showing smoke can cause measurable damage to the eye’s surface.

The ���������¼� Sydney-led study, published in , showed exposure to bushfire smoke can destabilise the tear film — a thin layer of fluid essential for clear vision — cause other surface irritation and damage and even trigger an inflammatory response.

While bushfire smoke is well known to cause respiratory and cardiovascular harms, its impact on vision and eye health have received little attention until now.

In a first-of-its-kind study, researchers from ���������¼� and the University of Tasmania safely exposed people to bushfire smoke in a laboratory, to measure the effect it had on their eyes. 

“We replicated the worst of the Black Summer bushfire season conditions,” said lead author Dr Suki Jaiswal from the ���������¼� School of Optometry and Vision Science.   “Our volunteer research participants were exposed to smoke levels similar to the height of air pollution, which was endured by communities in Canberra in early January 2020.”

Eighteen healthy adult volunteers attended the University of Tasmania’s facility, where they were seated 1.5 metres from a controlled burn of native vegetation for 15 minutes, while wearing protective respirators and fire-retardant overalls to ensure the smoke only affected their eyes, not their respiratory system or skin.

During the experiment, smoke levels were well above international air quality guidelines and averaged above the peak pollution recorded in Canberra during the Black Summer bushfires. However, participants were only exposed for 15 minutes — a much shorter duration than the one to two days of smoke pollution experienced in the capital.

Measuring the impact

Clinical measurements taken before and after exposure revealed significant increases in dryness, discomfort, redness and staining of the cornea. Tear samples, collected from 16 participants, also showed elevated levels of interleukin-1β — a pro-inflammatory molecule linked to tissue damage.

“We found that smoke exposure causes an inflammatory response on the eye surface, which is the underlying mechanism for many common eye conditions like allergic and dry eye disease,” Dr Jaiswal said. 

“This gives us a mechanistic understanding of how the eye responds to smoke particles, and suggests that anti-inflammatory therapies may be useful when patients present with smoke-related eye symptoms.”

Researchers also observed decreased tear film stability, which plays a critical role in protecting and lubricating the eye surface, said senior author Professor Isabelle Jalbert also from the School of Optometry and Vision Science. 

“Our tear film is really complex and important to allow us to see clearly and when it's damaged, for example when we have dry eye, it can become unstable and evaporate more quickly which can have consequences like blurry vision and discomfort.”

The research builds on the findings from a previous field study, which found firefighters experienced eye surface damage after controlled burns, and revealed gaps in eye protection and recovery practices.

Together, the lab and field studies are the first to demonstrate how bushfire smoke affects eye health in both controlled and real-world settings.

Next steps

The researchers say more studies are needed to understand the longer-term impacts of bushfire smoke on eye health, including how the ocular surface recovers over time and whether treatments such as anti-inflammatory eye drops could help manage symptoms.

While this study was limited by its small sample size and short exposure duration, it provides controlled evidence that bushfire smoke can directly affect the eye’s surface — highlighting the need to better integrate eye health into public health messaging during fire events to better protect the public.

The researchers say public health guidelines should be updated to reflect the risks to eye health during major bushfire events, to help protect vulnerable groups and the wider community.

Tips to protect your eyes from smoke

• Stay indoors when air quality is poor and use air purifiers if available, especially if you have dry eye or other sensitivities.

• Use non-preserved artificial tears regularly to flush out smoke particles and relieve dryness.

• Sterile saline can also be used to flush eyes, but tap water should be avoided when possible.  

• Avoid rubbing your eyes, which can worsen irritation and damage the surface.

• Wear wraparound or tight-fitting sunglasses outdoors to shield your eyes from particles.

• Switch to glasses if you wear contact lenses, as smoke can make lenses uncomfortable.

• Apply a cold compress to soothe eye irritation or inflammation.

• See your optometrist if symptoms persist — they may recommend targeted treatment.

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