Leading NHS eye surgeons say the government's introduction of new private mobile clinics will have a "catastrophic" effect on the services they offer.
The centres aim to cut waiting times
The BBC has learned local health planners are being forced into signing contracts for the new diagnostic and treatment centres.
Surgeons claim the units - which the government says will cut waiting times for minor surgery - will drain NHS income by up to half, and limit their ability to treat patients with chronic eye disease.
They also predict the move could mean restricting training and research, the closure of smaller outreach clinics and redundancies.
Health minister Lord Warner said there had been "misconceptions" about the reforms.
The new centres would offer up to 250,000 operations a year, with the aim of taking pressure off local NHS services across the country, according to the Department for Health.
But specialists at Oxford Eye Hospital - a leading UK centre specialising in eye surgery - have warned the viability of their unit will be threatened by the number of procedures private contractors have promised.
John Elston, a consultant surgeon at the hospital, told BBC Radio 4's Today
programme the private scheme was "a serious threat".
"The cataract work subsidises the work in chronic eye disease so it could
well mean that we would lose numbers of our trainees and if we lose staff, then we lose the ability to offer the full range of services," he said.
"You need a critical mass to attract the referrals and to provide the
Mr Elston said the unit was already set to meet government targets on waiting
Primary care trusts (PCTs) - which organise healthcare locally - were given a large amount of autonomy over where they choose to send their patients for treatment.
They are given control of 75% of total health budgets for their region.
But when three Thames Valley PCTs made a joint approach to NHS bosses asking to opt out of the diagnostic and treatment centre for their region, they were refused.
The Department of Health said it would create "insurmountable problems" in the viability of the contracts with the private firm, documents have revealed.
The cost of a cataract operation at one of the new centres, according to documents, would be more than under existing NHS services.
In a speech to NHS chief executives on Thursday, Health Secretary John Reid said: "We want to empower and enable all patients and clinicians to make shared and
sustainable decisions about their health and social care needs."
He added: "The NHS needs more money and autonomy going to the front line."
In response to the comments from Oxford, a spokesman for the Department of Health said final arrangements for the centres had yet to be agreed.
He said: "The diagnostic and treatment centre will be a series of mobile units that can travel across a wide area in order to meet patient need and will therefore be operating in areas beyond the Oxford Eye hospital's catchment area.
"While these units will concentrate on simple cataract procedures the Oxford Eye hospital will continue to provide a wider ranging ophthalmic service for patients."
"There are absolutely no plans to close down the Oxford Eye Hospital as this unit will serve the whole of the Thames Valley.
"The consultants will now be actively discussing how they can work alongside the DTC in order to deliver the best possible ophthalmology services to the Thames Valley region."
Liberal Democrat health spokesman Evan Harris - who brought the story to light - said the government had made it very clear the centres would be for additional capacity and that operations
would not be transferred out of the NHS.
But it had now "reneged" on agreements about cost and the non-involvement of NHS staff, he claimed.
"It's a breach of the promise. It doesn't offer value for money and, as we heard from the surgeons, it destabilises the NHS because the routine stuff,
which is the simple stuff, subsidises the work they do, which they will be left with, which is chronic disease and the simple cases."
Shadow Health Secretary Dr Liam Fox said: "John Reid knows this is bad for patients, completely undermines his own Diabetes National Service Framework, will devastate local eye services and is completely unnecessary."
He accused the NHS of "bullying" local consultants in order to force the change through, adding: "John Reid spent this week going round the UK, telling doctors and nurses how highly he values their services. Given this shocking evidence, what would he do to people he didn't like?"