An eye specialist has voiced concerns about nurses making decisions that "go beyond their training", after a woman was left virtually blind in one eye.
Claire Holmes, 24, from Worcestershire, twice visited the minor injuries unit at Kidderminster hospital in 2008.
Nurses she saw prescribed ointments, but they did not refer her case.
Ophthalmologist Paul Chell said by the time she was referred she had lost 95% of the sight in her eye. The trust has now changed its referral policy.
Miss Holmes wore contact lenses, which some doctors believe can increase the risk of developing a corneal ulcer that destroys vision, as the lenses can scratch the cornea.
Paul Chell, the clinical director of ophthalmology at Kidderminster General Hospital at the time, sent an e-mail to the chief executive John Rostill in which he said the case was indefensible.
The e-mail, obtained by the BBC, claims that Miss Holmes was the second eye patient who had been put at risk in two weeks in September 2008.
Mr Chell wrote: "This had come on top of another risk from another nurse the week before where completely inappropriate decisions had been made on one of my [highly complex] cornea transplant patients.
"I had already written to the nurses pointing out the danger of treating complex eye conditions beyond their skills.
"I am afraid that this is an area of care (not only in Worcestershire) where nurses in general acute care settings are making decisions way beyond any training or skills they possess.
"I have for many years stated that putting nurses in these positions will eventually lead to a wave of litigation."
Miss Holmes, from Hagley, first attended Kidderminster General Hospital on 13 September 2008.
She was told that she had a scratch and was given an ointment. The following day she was in pain, but was told over the phone to continue using the ointment.
Her mother became so worried about her condition that she took her back on 15 September.
Another nurse briefly examined Miss Holmes and prescribed another ointment with instructions to persevere for another 24 hours.
By 17 September there was a discharge from her eye and she could not see out of it.
When Miss Holmes went back to hospital for a third time she was assessed by an ophthalmologist who examined her with a specialist lamp, diagnosed an ulcer and referred her to the Midlands Eye Centre in Birmingham.
"I am angry that the hospital didn't do its job properly," Miss Holmes said.
"You put your trust in the hospital because you think that is the best place to go, which obviously it was not, and they diagnose you wrongly. So because of their mistake I am worse off."
Solicitors acting on Miss Holmes' behalf have obtained substantial, undisclosed, compensation.
Tim Deeming, of Irwin Mitchell, said the firm's expert evidence was that if Miss Holmes had been seen by an ophthalmologist on the first day, she would not have lost her sight.
"The ulcer at that time was on the very top of her eye so she could have been treated and saved all the sight in her eye.
"If she had we would not be here today and Claire would not have suffered the traumatic damage she has."
Earlier this year, the BBC tried using the Freedom of Information Act to find out about eye injuries, but the trust denied there had been any.
Worcestershire Acute Hospitals Trust also denied there had been any communication to a senior manager or any actions taken as a result of concerns.
The trust said it was a misunderstanding. Miss Holmes' case should have generated a serious untoward injury report, but it was never written up.
John Rostill, the trust's chief executive, said he apologised unreservedly for the upset and distress that had been caused by the delay in Miss Holmes' treatment.
"We recognise that Claire should have been referred to an ophthalmologist within 24 hours. Clearly we failed to meet this criteria.
"This incident occurred in 2008 and since then we have reviewed our procedures for patients presenting with an eye problem.
"Patients with eye injuries or conditions are now X-rayed on arrival as routine and processes are in place to transfer, if necessary, to a consultant ophthalmologist 24 hours a day," he said.