The one reported by Waikato DHB saw a patient with neovascular glaucoma who went from being able to see a couple of meters to only seeing movement because they were seen six months after their previous appointment instead of the three months it was supposed to be.
The data also showed that at the end of last year there were more than 20,000 people around the country who were overdue for a follow-up ophthalmology appointment.
Counties Manukau had the highest number of patients overdue for appointments with 5649 overdue at the end of November.
Acting chief executive Gloria Johnson said the number of outpatient ophthalmology reviews the hospital did had increased exponentially since 1999 from just over 6000 referrals a year to almost 17 in the 2016/17 financial year.
She said the main reasons were an increase in diabetic patients requiring regular review, the ageing population and improvements in interventions which may save sight but require ongoing follow-up such as the Avastin eye injection for macular degeneration.
There was also a national shortage in the ophthalmology workforce which had made it difficult for many health boards to hire new specialists to keep up with the growing need, she said.
Johnson said the hospital had received more than $220,000 from the Ministry of Health's to get a second pascal and an ophthalmic technician to help monitor and test patients. In June the hospital also opened a new ophthalmology suite with three more clinic rooms and a number of diagnostic rooms.
She said the aim was to clear the backlog of overdue patients by the end of June next year.
A spokeswoman for the Royal Australian and New Zealand College of Ophthalmologists said there was concern about any patient having to wait too long for eye care appointments.
"Some eye diseases, such as macular degeneration or diabetic retinopathy, require regular and ongoing review and treatment. New Zealand hospitals see a huge number of ophthalmic patients each year and it is important that there is adequate supply to meet this demand, particularly as missed appointments can result in adverse outcomes."
She said health boards were now working to refine processes to eliminate problems.
Association of Salaried Medical Specialists executive Director Ian Powell said it was a huge concern so many patients were overdue for appointments.
He said the college had raised concerns about under-resourcing of the department some time ago which was overlooked or misunderstood by the Ministry of Health.
Labour health spokesman David Clark said the number of overdue appointments was unacceptable.
"The scale of the problem is horrific," he said. "New Zealand is a first world country and people have a reasonable expectation they won't go blind waiting for services."
He said more funding was needed to make sure every New Zealander could access affordable, quality healthcare.
Ministry of Health group manager integrated service design Clare Perry said there had been rapidly increasing demand in recent years because of the development of innovative new treatments which require regular monitoring and follow up, an increase in prevalence for some conditions, and an ageing population.
"In order to support DHBs' actions, the Ministry of Health made available $2 million nationally to assist DHB teams to implement or improve care models to best support their local district's eye health."
The Ministry has also established a National Ophthalmology Expert Advisory Group to provide advice on further actions that could be taken.
Number of patients overdue for eye treatment at the end of 2016
Auckland and Waitemata: 4807
Canterbury: 2773
Counties Manukau: 5649
Hutt Valley: 398
MidCentral: 239
Nelson Marlborough: 839
Northland: 209
Southern: 3709
Waikato: 1720
