Overview: Conjunctivitis in Japan
Conjunctivitis (結膜炎, *ketsumakuen*) — commonly known as "pink eye" — is an inflammation of the conjunctiva, the thin transparent membrane covering the white part of the eye and the inner surface of the eyelids. It is one of the most common eye conditions seen at Japanese ophthalmology clinics and affects travelers frequently due to the high-exposure environment of shared spaces, tourist attractions, and Japan's significant allergen load.
For international visitors, three scenarios most commonly lead to conjunctivitis:
- Allergic conjunctivitis from cedar pollen (February–April), grass pollen, or other environmental allergens
- Viral conjunctivitis spread through contact in crowded tourist venues, hotels, or public transport
- Bacterial conjunctivitis from contact lens hygiene issues, contaminated water, or touching eyes with unwashed hands
Japan's ophthalmology (眼科, *ganka*) network is excellent, with eye clinics in every neighborhood and specialists accustomed to seeing patients with a wide range of conditions. Same-day appointments are generally available, and treatment is effective and affordable relative to many Western countries.
Types of Conjunctivitis and Their Characteristics
Type | Cause | Discharge | Contagious? | Treatment |
|---|---|---|---|---|
Viral | Adenovirus, enterovirus | Watery, clear | Highly | Supportive only; may resolve in 1–2 weeks |
Bacterial | Staphylococcus, Streptococcus, Haemophilus | Thick, yellow/green, crusting | Moderately | Antibiotic eye drops |
Allergic | Pollen, dust mites, pet dander | Watery, clear | Not contagious | Antihistamine drops, avoid triggers |
Epidemic keratoconjunctivitis (EKC) | Adenovirus (specific strains) | Watery, then mucopurulent | Very highly | Supportive; specialist care |
Epidemic keratoconjunctivitis (流行性角結膜炎, *ryūkōsei kakuketsumakuen*) — known in Japan as "EKC" — is a particularly severe form of viral conjunctivitis caused by specific adenovirus strains. It can cause corneal involvement and vision changes and is extremely contagious. Japanese schools and workplaces take EKC very seriously; infected individuals are expected to stay home. Travelers who develop rapidly worsening eye redness with pain and light sensitivity should see an ophthalmologist promptly.