DRP has been routine in the eye-health profession for about a decade, but the quality of imaging is improving steadily.
It allows optometrists to easily compare changes over time and potentially catch sight-threatening or even life-threatening conditions early, giving the best chance of successful treatment.
One such creeping condition is glaucoma, which causes damage to the optic nerve resulting in permanent loss of vision; it has been called the silent thief of sight.
The condition is not yet curable but vision can be preserved with early treatment.
About 3 per cent of New Zealand's population have the disease, and 10 per cent among those over age 70.
If you have a family history of glaucoma you are 10 times more likely to get the disease.
Australian optometry chain Specsavers has made DRP standard in all its stores, giving a detailed photograph of the inside of the eye which is made available immediately on an iPad.
Glenyce Anderson, 66, has experienced first-hand just how crucial DRP is after her optometrist identified a melanoma on the back of one of her eyes. Like skin cancer, the melanoma could have killed her.
"I'm extremely relieved it was discovered in time, as I don't want to think about what would have happened had it not been," she says.
"My optometrist referred me to an ophthalmologist straight away and I was able to get treatment immediately."
Tony Han, of Specsavers Mt Maunganui, tested Glenyce's eyes at a routine eye examination and noticed the subtle raised lump at the back of her eye.
"This condition is rare and can be difficult to detect and monitor for progression at its early stage using traditional instruments like an ophthalmoscope, which is a magnifying lens with a light on the end that we shine into people's eyes to see the back of their eye," Han says.
"This is a bit like looking through a keyhole and trying to make out a picture hanging on a wall on the other side.
"The beauty of the digital camera is that we get a sharp colour picture of the retina, which shows us in incredible detail exactly what's happening inside the eye. Having a photo means we can study it closely, keep a permanent record so we can compare images taken at a later date and monitor them for changes - and even share them with specialists if we need to refer people for further treatment.
"This can be sight-saving and potentially lifesaving."
Retinal photographs are stored permanently, allowing optometrists to bring up patients records instantly and track their eye health more efficiently and accurately.
Han says it is important for people to understand the far-reaching benefits of an eye test.
"People often think that an eye examination is just about updating their glasses prescription, but there is so much more to it than that," he says.
"In an eye examination we are also looking out for signs of serious medical conditions such as hypertension and diabetes, as well as sneaky eye conditions like glaucoma that can destroy the peripheral vision gradually before people even notice they have a problem."
