There has been a rise in the number of fungal infections of the eye among contact lens users in Singapore.
A total of 39 cases were detected, up from the 22 reported previously.
The Health Ministry has also strongly urged those using Bausch and Lomb's ReNu multipurpose solution to stop, until investigations are complete.
Bausch and Lomb's ReNu solution has a strong association with the fungal infection cases, says the Health Ministry.
A total of 35 out of the 39 contact lens wearers infected with the Fusarium solari fungus said they had used the solution.
Four were unsure of the brand they use while at least one use a different brand.
Eye doctors say that the situation is worrying as fungal infections among contact lens users is uncommon.
It is also more difficult to treat, although the fungus itself is not contagious.
Dr Chan Wing Kwong, Head of Refractive Surgery Service at the Singapore National Eye Centre, said: "The reason that we are worried is that fungus is slow to present. In fact due to the biology of the fungi, they grow quite easily in the eye without causing too many symptoms and sometimes it can be days or weeks later before they start to present.