But extended-wear lenses must be cleaned after they have been in the eye, and the cost is $90 to $200 a year.

Many users of the extended-wear lenses developed eye irritations, ulcers, infections and allergic reactions.

Several predict a resurgence of the same kinds of complications attributed to the original extended-wear lenses.

Both daily-wear and extended-wear lenses are available for less than half the price of disposables.

Daily-wear lenses last for about a year; extended-wear lenses, about nine months.

The F.D.A. also wrote to more than 60,000 eye care professionals to ask them to tell patients who already use extended-wear lenses of the new caution.

The lawsuit is the second in two weeks to be filed against Bausch & Lomb over its highly promoted extended-wear lens.

Bausch officials say the new lens, called Pure Vision, is safer and more comfortable than any other extended-wear lens on the market.

The agency has paid greater attention since 1983, when extended-wear lenses were linked to serious infections.

The study found that users of extended-wear lenses had a risk 10 to 15 times as great as those who removed them at night.