Thousands of cataract patients in the South West are to be contacted over a faulty replacement lens.
The Royal Eye Infirmary has to contact 5,000 patients
Officials are now working out the best way of telling patients operated on at Plymouth's Royal Eye Infirmary over a three-year period.
They estimate that about 200 of the patients out of some 5,000 given the lens may need further surgery.
It follows a recall by the manufacturers after reports that some lenses became cloudy.
During a cataract procedure, the patient's own cloudy lens is replaced with a synthetic one. But it has emerged that 5,000 patients will need to be told the replacement they have been given could be faulty.
It follows a recall by the manufacturers after reports that some became cloudy.
The problem developed because of the way the lens was packaged, affecting a small proportion.
Manufacturers Bausch and Lomb said: "Given that the silicone-packaged product was removed from the market almost three years ago, we believe that this percentage will remain small and, over the next year or so, will disappear altogether."
The affected patients were all given the lens between December 1997 and May 2001.
Plymouth Hospitals Trust is trying to determine the best way to contact the patients with the affected lens.
It will then have to try and identify which of the estimated 4% of patients will develop cloudy vision.
The Trust said in a statement: "We'd like to reassure patients that there are no immediate harmful issues with the lens and that any problems will develop slowly and gradually."
A team has been set up to review the situation. It said about 40 patients already had lenses replaced so far.
Plymouth Hospitals Trust has set up a helpline for people to contact them if they are at all worried on: 0845 600 8086.