What are the common misunderstandings about coloured contact lenses?
This answer is a draft. It stays unpublished until legal review and source verification are complete.
Coloured contact lenses ("karakon", カラコン) are widely worn by young people in Japan, and Japanese coloured lenses are popular with visitors too. The misunderstanding that "they are fashion items, so just general goods" has caused eye problems, and the rules changed in 2009.
The rules and the numbers
| Item | Content |
|---|---|
| Category | Specially controlled medical device (Class III). Since November 2009, non-corrective fashion lenses are in the same category |
| Sale | Only by shops and online sellers licensed to sell specially controlled medical devices. An approval number (e.g. 2270…) is shown on the product |
| Eye examination | An examination before purchase and regular check-ups are recommended by the government. Many shops sell without a prescription, but fit must be confirmed by an eye doctor (眼科, ganka) |
| Main problems | Corneal scratches, infection (corneal ulcer), allergic conjunctivitis. Severe cases of reduced vision have been reported |
| Enquiries | The National Consumer Affairs Center of Japan continues to receive enquiries about eye injuries from coloured lenses |
- Before the 2009 rules, fashion coloured lenses were sold as general goods, and eye injuries became frequent, which led to regulation.
- Because of the pigment layer, many coloured lenses have low oxygen permeability, and the wearing time on the label (mostly within 8–12 hours a day) must be kept.
- Daily disposables (1-day) must not be reused. Two-week and one-month lenses need daily cleaning and disinfection.
[Verify] Check the month and year the rules took effect against the MHLW notice, and the case reports against National Consumer Affairs Center and Japan Contact Lens Society materials.
Misunderstanding 1｜Without prescription power, there is no effect on the eye
Whether a lens has power has nothing to do with the strain on the eye. Any lens covers the cornea and reduces oxygen, and many coloured lenses let even less oxygen through because of the pigment layer.
Misunderstanding 2｜Cheap lenses without an approval number are the same product
Products without an approval number may not be sold in Japan. With personal imports and flea-market apps, there are reports of pigment leaching out and lens specifications that do not fit.
Misunderstanding 3｜You can buy them without seeing an eye doctor, so there is no need to
"Can buy" and "fits" are different things. A lens whose base curve (BC) and diameter (DIA) do not match damages the cornea. An examination before purchase, then once every 3–6 months, is recommended.
Misunderstanding 4｜Wearing a daily lens for two days saves money
A 1-day lens is designed to be thrown away after one wear, and re-wearing it causes infection. For cost, a two-week lens looked after properly is the safer choice.
Misunderstanding 5｜It is fine to lend them to a friend
It is a direct cause of eye infections. Contact lenses are for one person only. If your eye is red or painful, or your vision is blurred, take the lens out and see an eye doctor.
---
Sources
- Ministry of Health, Labour and Welfare, "Designation of coloured contact lenses not intended for vision correction as specially controlled medical devices" [視力補正を目的としないカラーコンタクトレンズの高度管理医療機器への指定について] (2009)
https://www.mhlw.go.jp/stf/seisakunitsuite/bunya/kenkou_iryou/iyakuhin/index.html
- National Consumer Affairs Center of Japan, "Eye injuries from coloured contact lenses" [カラーコンタクトレンズによる目の障害]
https://www.kokusen.go.jp/
- Japan Contact Lens Society, "Safe use of coloured contact lenses" [カラーコンタクトレンズの安全な使い方]
https://www.clgakkai.jp/
⚠️ Editorial note: the source URLs above were identified by search. Our working environment cannot reach go.jp domains, so the contents have not been checked against the text. Verify every source before publication and record who checked it and when.
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