"A light went on . . . I thought: 'Cripes, I have done it'," Dr Duncan Adams said.
An honorary research fellow at the University of Otago, Dr Adams (83) says he is anything but retired.
Keeping abreast of the latest scientific developments, several months ago the St Clair man stumbled across a diagram of an eye and immediately realised the importance of his discovery.
The diagram showed a diabetic eye compared to a normal eye, and "it was one of the most beautiful diagrams I have ever seen".
"I contacted the guy who did the picture but they didn't realise what they had. They just thought I was some hick from New Zealand."
What the diagram showed was the loss of pericytes, a type of cell, in people with type-one diabetes.
"All the information was there, but no-one has come up with the theory."
Dr Adams' theory is a radical shift in the treatment of blindness and "the therapeutic implications are immense".
"It is now very likely that the blindness associated with type-one diabetes is not due to defective control of blood glucose levels," he said.
He advocates a switch from "ineffectual tight glycemic control" to immunotherapy to stop the onset of blindness for type-one diabetics.
Type-one diabetics are encouraged to monitor blood sugar levels to control the onset of blindness.
But, by destroying a patients' immune system with immuno-suppressive chemotherapy, it was possible to eradicate the cells which cause life-threatening blindness, he said.
Following chemotherapy, a patient's immune system could be restored with stem cells taken from the patient's own bone marrow.
"This treatment is available now," he said.
"It means that effective treatment is at last available."
Dr Adams would like to work further on the means to isolate the autoantigen in the retina and selectively destroy the cause of blindness, leaving the rest of the immune system intact.
"This will be the ideal cure, and could be five years away," he said.
His paper, "Autoimmune destruction of pericytes as the cause of diabetic retinopathy", was published in the latest issue of the Clinical Ophthalmology journal.
University of Otago ophthalmology professor Anthony Molteno said Dr Adams' research was "very promising and worth pursuing".
"Diabetes is a huge burden on people and on the health system and it is increasing every day. We are waiting for answers and this looks very good.
University of Otago human nutrition and medicine professor Jim Mann said Dr Adams' theory "sounds fascinating, but I would be interested to see more detailed evidence".
Diabetes New Zealand president Mike Smith (58), of Napier, said diabetics and their families would closely follow the progress of Dr Adams' findings.
Diabetes
• More than 15,000 New Zealanders have type-one diabetes.
• People who do not make any insulin (or very little) have type-one diabetes.
• Diabetes has been the leading cause of blindness in New Zealand.
Source: Diabetes New Zealand
