As a qualified doctor and an international with 97 caps, Jamie Roberts is better equipped than most to give a player's perspective on the physical toll of a career in rugby union.

When it comes to head injuries, however, he stresses that rugby union - which only turned professional 25 years ago - is still learning.

Earlier this month, a group of former players announced they were taking legal action against the game's authorities for negligence.

Among them were Steve Thompson, a World Cup winner with England in 2003, and former Wales number eight Alix Popham, who had been diagnosed with early signs of dementia and said repeated blows to the head were to blame.

Head injuries are worryingly common for most players in the modern era and Roberts is no different, notably fracturing his skull after a sickening collision with Australia's Stirling Mortlock in 2008.

Since then, Roberts believes there have been important changes to rugby union's concussion protocols and he says he is "proud" to play a sport which continues to review its laws to improve players' safety.

"When I look back over my career, the changes which have been made to look after players have been significant," says the Dragons player, a member of two World Rugby bodies - its players' council and high performance rugby committee.

"It's important these recent events - the players coming out - add to that body of evidence and allow the decision-makers to make the right, informed choices.

"We must remember rugby is relatively young as a professional sport and the evidence around head injuries is relatively limited.

"That scientific evidence will grow over time and no doubt what's happened over the past few weeks is going to add to that body.

"In a year's time, five years' time, 10 years' time, we're going to be in a better place, and the governing bodies are going to be in a better place, to make informed decisions to look after the players as best possible.

"It's desperately sad, the story of those players coming out, but it's important this story is out in the public sphere and that the game is honest about this topic."

Thompson and Popham gave deeply moving accounts of their life-changing brain injuries, which have had a profound effect not only them but on their families and friends.

Others, such as former Dragons centre Adam Hughes, have not had the same diagnosis, but say they still feel the effects of concussions years after retiring.

Although Roberts expects to suffer physically in retirement, he does not believe there is enough evidence for him to worry that he might face similar brain damage later in life.

"When it comes to my knees and shoulders, I know at some point it's going to catch up with me. I'm fully expecting that, like most players," Roberts says.

"What's difficult is around head injuries. It's difficult to even know. We don't really know the full effect of the game on the brain, so it's very difficult to envisage anything.

"I'm not worried because there's not that evidence to inform me that I'll suffer in the future.

"Let's not forget, it's a brutal sport. There are a lot of collisions and a very high risk of injury, and it's important players understand that when they come into the game as young players."

The impact of recent discussions about head injuries in rugby union has been far-reaching, with one of the world's leading experts in the field expressing his view on the matter.

Dr Bennet Omalu is the pathologist who discovered the brain disease chronic traumatic encephalopathy and rocked American football with his research into the brain injuries sustained by players in the National Football League (NFL).

In 2011, a group of former American football players started a class action against the NFL and won a settlement worth about $1bn (£700m).

Dr Omalu told the BBC Scrum V podcast last week that rugby union's governing bodies must reach a settlement with the former players suing for alleged negligence or the sport would be "gradually be removed from mainstream culture".

Asked whether the latest developments could be a watershed moment for rugby union in its attempts to deal with head injuries, Roberts says: "Let's remember the NFL research and everything that happened in the NFL more or less snowballed after a few of the older NFL players passed away, and they were able to view their brains under a microscope.

"I've read it and heard quite a few players mention that, until that first cohort of professional rugby players end up passing and maybe donating their bodies to medical science and allowing the powers that be to view their brain under the microscope, I don't think rugby will fully understand the effect of rugby on brain injuries.

"That might be five years, 10 years, 20 years away. Again, we go back to the point that professional rugby is only 25 years old.

"Until that point, we're talking about clinical evidence, clinical symptoms. The players who have recently come out, their evidence adding to this body of evidence which is allowing the powers that be to make the best-informed decisions to protect the players."