Nearly 700 people have contacted a helpline set up for people concerned they may have been fitted with a faulty cataract lens implant in Plymouth.
The Royal Eye Infirmary is following up 294 calls to the helpline
Last month, manufacturers Bausch and Lomb issued a national recall after reports that some lenses became cloudy.
Plymouth's Royal Eye Infirmary estimated that around 200 of the 5,000 patients given the lens over a three-year period might need further surgery.
Plymouth Hospitals Trust set up a helpline for worried patients to ring.
The Trust said 692 people had contacted the helpline and they were following up 294 of the calls which reported symptoms that could be associated with the Hydroview lens, or where people sounded as though they needed reassurance.
The trust is uncertain whether these cases are linked with the faulty lens, so there are no figures available for the number of people who need treatment as a result.
The problem with the Hydroview lens implant was made public in September. It can potentially turn opaque over time, leading to cloudy vision.
The problem developed because of the way the lens was packaged, affecting a small batch.
The affected patients were all given the lens between December 1997 and May 2001.
The Hospitals Trust helpline number is 0845 600 8086.