Scientists are hoping a new method for diagnosing eye disease will allow doctors to spot glaucoma early enough to save a patient's sight.

A new method of diagnosing eye disease has been developed by scientists using a technique that involved patients watching episodes of Dad's Army.

By scanning and analysing their eye movements, the researchers were able to identify cases of glaucoma with almost 80 per cent accuracy.

The irreversible condition, caused by progressive damage to the optic nerve, leads to loss of peripheral vision and eventual blindness.

An estimated half a million undiagnosed sufferers are thought to be living with the disease in the UK.

Scientists hope the test will in future allow clinicians to spot cases earlier, allowing treatment to begin while a patient's sight can still be saved.

In a proof-of-principle study involving 44 elderly glaucoma patients and 32 healthy individuals, the system identified 79 per cent of those who had the disease.

"These are early results but we've found we can identify patients with glaucoma by monitoring how people watch TV," lead scientist Professor David Crabb, from City University London, said.

"Once the damage is done it cannot be reversed, so early diagnosis is vital for identifying a disease which will continue to get more prevalent as our population ages."

The participants, who had an average age of 69, watched TV and film clips on a computer, including episodes of an old favourite, Dad's Army.

At the same time, their eye movements were tracked and the information fed into a computer that plotted the saccade patterns on to a grid and was able to spot subtle differences between them.

Certain patterns, only clearly discernible by the computer, correlated with having glaucoma.

"What we've done is use a mathematical technique to find patterns in these grids that allow us to distinguish between the groups," Prof Crabb said.

Copyright AAP 2014.