"In ophthalmology, many of the conditions we treat are chronic, often with few obvious warning signs, and patients are at risk of losing their vision without regular and timely specialist check-ups."
Patients with macular degeneration could end up with some remaining peripheral vision, but glaucoma could lead to total blindness, he said.
Last year, four Southland patients were revealed to have lost sight, in a report released with the Health Quality and Safety Commission's annual statement on serious and sentinel events.
The commission will publish its latest report next week.
Today, its chief executive, Janice Wilson said: "There has been a notable increase in ophthalmology events reported by Southern and Nelson Marlborough DHBs in the 2015/16 Learning from adverse events report."
"These events include delays in people getting follow-up appointments to see ophthalmologists, and in some cases eye conditions have deteriorated."
No other DHBs have reported high numbers of ophthalmology events, but DHBs vary over what they consider a reportable event.
Wilson said: "The commission encourages reporting of ophthalmology events, and commends DHBs like Southern and Nelson for showing leadership in this.
"This finding is a prompt for other DHBs to look closely at their ophthalmology services to ensure people are being seen in a timely manner, with high-risk patients prioritised."
The senior doctors' union says the problem partly results from state health spending not keeping up with population growth and health cost inflation.
"It is a serious national problem that ophthalmologists warned the Minister of Health about around a year ago," said Ian Powell, executive director of the Association of Salaried Medical Specialists.
"New developments in treating macular degeneration [the use of the medicine Avastin] significantly increased patient demands on public hospital eye services, with a lack of staff to treat many other chronic visual illnesses.
"It has been made worse by the Government's rigid adherence to arbitrary targets. Targets are about the patient's first admission for treatment, not the follow-ups.
"... many of these bad outcomes involve the lack of follow-up treatment because they can't be counted for the target."
Chew appealed to the Government to allow specialists to decide when to see patients, on grounds of medical need, rather than having to see new patients within four months to satisfy the target.
Eye services had increased the number of patients' appointments by measures such as adding weekend and after-hours clinics, training nurse specialists to help with treatments, and by ranking follow-up appointments by patient risk.
But this had proven insufficient and now more money was needed, to hire more staff.
He said that at one hospital where he works, the demand had increased from 50,000 annual "patient contacts" five years ago, to 90,000 now.
The Health Ministry said the average waiting time for opthalmology treatment had reduced from 66 days in December 2014, to 59 days in August 2016.
Health Minister Jonathan Coleman said of the Southern DHB, "They have got to do a lot better."
He said that eye specialists had not specifically raised this issue when they visited him.
When asked on his way into the House if patients' health had been compromised by waiting times, he said: "That needs to be looked at. As I said, demand for ophthalmology processes has increased greatly."
He said a new set of criteria would soon enable better prioritisation of patients based on their clinical needs.
The Southern DHB's interim chief executive, Chris Fleming, told the Otago Daily Times more cases of harm could be identified as the backlog was cleared, particularly at Dunedin Hospital.
"We are on top of it in Southland. The numbers in Dunedin at this stage are still rising,'' he said.
An external investigation team had been engaged to investigate the cases.
Of the 30 patients who suffered harm due to the delays, 21 were in Southland, and nine were in Dunedin.
Last year, In response to Otago Daily Times inquiries, the board disclosed another two cases, in addition to the four Southland sight-loss cases revealed by the commission, making a total of six at that time. It said extra staff had been added in Southland, as well as other measures.
The Otago Daily Times featured the story of Gore man Koby Brown, who, aged 22 at the time, lost the sight in one eye to glaucoma and said he had been told by Southland Hospital staff to be "patient'' about his overdue appointment.
Mr Fleming admitted yesterday the board should have done more at that time.
"To be blunt, we didn't do enough [then].
"Clearly, the numbers speak for the results.
"We're putting this out there publicly now to make sure that we are letting all those 4600 patients know, and that then we are both publicly and privately held to account to make sure we clear this problem.
"We have a plan in place in Invercargill because the issue is more known there, and we're still developing a detailed plan [in Dunedin].''
Mr Fleming had requested an extra ophthalmologist and optometrist be recruited immediately in Dunedin.
In Dunedin, 37 per cent of all ophthalmology appointments are overdue.
In an interview yesterday, Mr Fleming and chief medical officer Dr Nigel Millar emphasised the high demand for a relatively new treatment for macular degeneration called Avastin.
Dr Millar said the service had become "overwhelmed'' because of the success of that treatment.
"It doesn't just affect the patients receiving Avastin, it puts demand on the whole service,'' Dr Millar said.
Avastin demand was cited by the board last year to explain the earlier cluster.
"I think you've heard what [Mr Fleming] said that we can see now we didn't do enough,'' Dr Millar said.
"People believed at the time that it would be enough.
"This is something we sincerely regret and want to apologise to any patients who suffered avoidable harm.''
The board is looking at new ways of managing some ophthalmology patients, which would involve GPs and nurses.
"We're doing some of that [already]. We've got some nurses now doing follow-up for patients with glaucoma,'' Dr Millar said.
The letter to patients, obtained by the Otago Daily Times, tells the patient they are among a large number whose appointments are delayed.
The backlog would be cleared over time, but patients with immediate concern about their vision would be seen urgently.
Affected patients could call 0800 866 000 or contact their GP. They could also call hospital nurses in Dunedin or Invercargill.
Southern GPs were told in an email yesterday about the situation. Cromwell GP Dr Greg White told the ODT he did not know why the DHB had done that.
"It's been a long-term problem, so we're not sure why they have notified us again about them,'' Dr White said.
- With Otago Daily Times
