A man from Stonely has raised concerns about the service at Hinchingbrooke Hospital’s glaucoma clinic.
John McCafferty, aged 67, is a 'high risk' patient and says in the last three months, the "normally excellent" service has deteriorated and is causing a huge level of frustration for patients.
Mr McCafferty has had several appointments cancelled, sometimes on the day and after he has arrived at the hospital, and been told he will need to go elsewhere for his eye treatment.
He says his biggest frustration is not knowing what is happening.
"No communication has been provided to patients," he said.
"Appointments are not being made or are being cancelled. Staff appear to have been instructed not to comment. Even for high risk patients, phone calls to chase missing appointments are met with 'I am sorry, there is nothing I can offer you'."
Mr McCafferty has been a patient at the clinic for 15 years and has undergone five eye operations and several procedures and believes the problems are due to a lack of qualified consultants and also some IT issues.
"Administration systems and staff appear to be under pressure," he said.
He has been told that the migration of IT systems between Peterborough City and Hinchingbrooke has been a "disaster".
"I was told the outpatients recording system was experiencing a busy and difficult time during implementation of a new hospital system. "Problems now seem to be flowing back through the system with local opticians and doctors being contacted by frustrated patients.
"I believe this situation requires urgent investigation as many thousands of patients are likely to be seriously adversely affected."
In a statement, Dr Kanchan Rege, medical director at North West Anglia NHS Foundation Trust, which runs Hinchingbrooke Hospital, said: "The glaucoma clinic currently has vacancies for permanent roles that we are actively trying to fill. We currently have two locum consultants in post and another starting shortly while we recruit to these roles.
"We would like to reassure patients that the service is not closing, we have a short-term solution in place which means patients are being seen and a long-term solution has been identified."