Why Does Eye Flu Spike Every Monsoon? An Eye Specialist Explains What's Behind It

Every year, as the rains arrive, so does eye flu. Red, itchy, watery eyes seem to spread through offices, schools, and households almost overnight. Why does this pattern repeat so predictably? Monsoon creates the ideal environment for the viruses and bacteria that cause conjunctivitis to spread more easily. Increased humidity, waterlogging, and more time spent in crowded indoor spaces during rain all contribute to faster transmission. Here is what she wants people to understand about this seasonal spike.

What Actually Causes Eye Flu During Monsoon?

Dr Neetu Gagneja Arora, Associate Director and Chief Eye Surgeon at Esskay Ortho & Eye Centre, New Delhi, explains that conjunctivitis during monsoon is usually caused by a highly contagious viral infection, and sometimes by bacteria. It spreads through direct contact with infected discharge, contaminated hands, shared personal items like towels or pillowcases, or contact with surfaces an infected person has touched.

Eye Flu in Monsoon

A 2025 review from Ophthalmology and Therapy finds that heavier rainfall raises rates of conditions like ocular toxoplasmosis, while rising temperatures and humidity are linked to more fungal eye infections and viral reactivations such as herpes zoster ophthalmicus. 

Air pollution also worsens dry eye disease, making the eyes more vulnerable to infection, and these effects hit rural, low-income, and tropical communities hardest.

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How Exactly Does the Weather Play a Role?

According to Dr Arora, several weather-related factors combine to make monsoon the perfect storm for conjunctivitis to spread:

• Humidity allows viruses and bacteria to survive longer on surfaces and in the air
• Waterlogging and dirty water increase exposure to contaminants that can enter the eyes
• People tend to gather more in enclosed, poorly ventilated spaces during heavy rain, increasing close-contact transmission
• Frequent hand-to-eye contact increases during monsoon, often unconsciously, due to wiping rain from the face or adjusting wet clothing and umbrellas

Can Both Eyes Be Affected, or Just One?

It can start in one eye and often spreads to the other within a day or two, according to Dr Arora, since it's easy to transfer the infection from one eye to the other through touching or rubbing.

In some cases, only one eye remains affected, but this isn't the norm. Close contact with the infected eye typically leads to both eyes being involved eventually.

A 2026 Delhi Journal of Ophthalmology review looked at over 3,000 conjunctivitis cases seen at a North Indian eye hospital during the July–August 2023 outbreak. It recorded symptoms and testing patients for the bacteria or viruses behind their infection. The researchers pointed to heavy rain, high humidity, waterlogging, and flooding as the main reasons cases surged so fast that monsoon. 

These conditions bring more dirt and germs into daily contact, while hygiene tends to slip when streets flood and water gets contaminated. Add crowded spaces and easy hand-to-eye spread, and infection moves quickly through a community.

Does Staying Indoors Actually Protect You From Eye Flu?

Staying indoors reduces exposure to contaminated water and crowded public spaces, which does lower risk, according to Dr Arora. However, it isn't a complete solution, since conjunctivitis spreads easily within households too, especially through shared items or close contact with an infected family member.

As she puts it, good hygiene practices remain important even indoors, regardless of how much time is spent outside.

How Can You Prevent Eye Flu During Monsoon?Eye Flu in Monsoon (1)

Dr Arora shares a practical list of prevention steps worth following during the season:

• Wash hands frequently, especially before touching the face or eyes
• Avoid touching or rubbing the eyes, particularly with unwashed hands
• Avoid sharing towels, pillowcases, handkerchiefs, or eye makeup
• Wear glasses instead of contact lenses if there's an outbreak in the household or community
• Avoid close contact with someone who has visible symptoms like redness or discharge
• Clean commonly touched surfaces regularly if someone at home is infected
• Avoid swimming in pools or other shared water sources during an active outbreak

What Is the Best Way to Treat Eye Flu Once It Happens?

Most cases resolve on their own, according to Dr Arora, but there are ways to ease symptoms and support recovery:

• Most viral conjunctivitis resolves on its own within one to two weeks with supportive care
• Cold compresses can help ease discomfort and swelling
• Artificial tears can relieve dryness and irritation
• Avoid touching or rubbing the eyes throughout the infection to prevent spreading it further or delaying healing
• If bacterial infection is confirmed, a doctor may prescribe antibiotic eye drops
• Discontinue contact lens use until the infection has fully cleared

Dr Arora adds an important caution too. See a doctor if symptoms are severe, involve significant pain, vision changes, or don't improve within the expected timeframe, since this could indicate a more serious eye condition needing specific treatment.

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Conclusion

Eye flu spikes every monsoon because the season creates near-perfect conditions for viruses and bacteria. It spreads through humidity, contaminated water, crowded indoor spaces, and increased hand-to-eye contact. Simple hygiene habits, avoiding shared items, and prompt care if symptoms appear can go a long way in reducing your risk during this time of year.