FORMER infantryman Anthony Provenza can't say for sure when his ears started ringing.
It could have been after the fierce gun battles in Oruzgan province. It could have been the ''immense amount of sound'' when a nearby foot patrol was hit by an improvised explosive device.
Or it could have been when a rocket landed 15 metres away, but failed to detonate.
''It would have killed us instantly,'' the 28-year-old Afghanistan veteran said. ''But just the sound of that rocket incoming was pretty loud.''
Two years on from a nine-month tour of Afghanistan, Mr Provenza is struggling to cope with hearing damage, post-traumatic stress disorder and a chronic back condition.
''I know it is from my service - of course it is,'' Mr Provenza said.
''I had to use my rifle and do my job as we all did. It was very hard on my ears and I do have hearing loss.
''I can't sleep because of the tinnitus and I can't hear people properly.''
He is not alone. Hearing damage - whether tinnitus or permanent hearing loss - is the most commonly accepted condition among soldiers that have served in Afghanistan, rivalled only by post-traumatic stress.
In the 2011 financial year, 276 compensation claims were determined concerning soldiers' loss of hearing. Nearly two-thirds were accepted. Another 228 claims were determined for tinnitus, with 78 per cent approved.
Few soldiers wear hearing protection, fearing it limits their ability to detect danger.
''It's probably one of those unspoken laws,'' said another member who recently returned from Afghanistan. ''Protecting your hearing takes a back seat versus saving your life or saving your mate's life.''
Among former servicemen who fought in Vietnam, the Department of Veterans' Affairs has approved more than 20,000 compensation claims for permanent hearing loss and almost 10,000 claims for tinnitus.
Now, the Defence Department issues headsets with noise-reduction technology designed to allow soldiers to communicate in loud environments, and hearing protection is commonly used in training.
Soldiers' hearing is tested according to their level of exposure, with those operating around extreme noise required to take an audiogram every six months.
However, a member recently returned from Afghanistan told The Age his hearing was tested only once every three years.
Mr Provenza said he was still waiting for compensation from the Veterans' Affairs Department, which initially told him his tinnitus was unrelated to his time in the army.
His lawyer, Greg Isolani, said hearing loss and tinnitus claims are now common among young soldiers who had seen combat.
Mr Provenza still uses medication he was given in Afghanistan to enable him to keep fighting after he injured his back, to quell the shooting pain in his left ear.
Unable to work, he survives on incapacity payments, and has moved back in with his parents. ''I'd rather have my health than any amount of money or any amount of pension,'' he said.