Football, like no other sport, is played by some of the most passionate athletes in the world. Their desire to play for some of the biggest clubs far exceeds our expectations. As fans, we can only enjoy a game that symbolises unity and strength.

When it comes to performing at an elite level, a footballer has to give everything, both physically and mentally. Injuries are part of the game, as the sport is extremely demanding.

Some of these top stars have had serious health problems, but they have still gone onto the football pitch and given an unparalleled performance.

From Petr ?ech, who is still nursing his wounds after the clash with Stephen Hunt in 2006, to David de Gea, who struggled with his oversight and became one of the world's best goalkeepers, it is inspiring to see how these athletes have overcome their shortcomings.

Here are five footballers who played with some of the worst health problems.

5. Edgar Davids - glaucoma

Davids is one of the most famous footballers of his generation and is often considered one of the best defensive midfielders of his time. Louis Van Gaal called him the "pitbull" because of his robust and dominant style of play, but he is also known for being, along with Patrick Vieira and Claude Makelele, one of the most versatile central midfielders of all time.

An important factor is that the former Juventus legend was seen wearing glasses almost the entire time during the game. This was due to a disease called glaucoma, where the optic nerve in the eye is damaged by genetic or other causes, limiting vision. There is no specific cure for this disease and it can only be controlled.

Despite this, Davids has managed to play most of his career without his performance being affected by glaucoma, which shows that he is a strong character.

4. David de Gea - myopia

The Spaniard is one of the best goalkeepers at the moment and has excellent skills as a goalkeeper. The kind of reflexes and awareness that he shows are factors that have helped him develop as a goalkeeper.

His tall stature and leadership qualities make him one of the most influential goalkeepers of his particular generation. The remarkable thing is that De Gea had all these qualities with a condition called myopia. He wore glasses almost all his life.

Interestingly, his start at Manchester United was not quite as expected, as he continued to make a series of mistakes. After further tests by Manchester United's optometrists, De Gea was found to have vision problems.

However, Sir Alex Ferguson didn't want to take any risks and ordered the Spanish goalkeeper to undergo laser surgery in the summer of 2012. Since then, De Gea has only gotten better and has cemented his legacy as one of the world's best goalkeepers.

3. Paul Scholes - Blocked vein in right eye

With 11 Premier League titles, 3 FA Cups, 2 Champions League trophies and 2 UEFA Cups under his belt, Scholes is one of the greatest and most decorated English midfielders of all time.The Manchester United legend played for almost two decades, appearing in over 700 games for the Red Devils and scoring over 150 goals. The biggest surprise is that he played with one eye for part of his career.

"At one stage I saw four balls coming at me, it was confusing. Believe me" - Scholes on his blurred vision.

After consulting several doctors, Scholes was diagnosed with a blocked vein that was causing internal bleeding in his right eye. He underwent an operation that required more than ten sessions because of the tangled nerves in his eye. Scholes returned in 2006 after six months and took part in one of the best seasons in Manchester United's history.

2. Petr ?ech - head injury

We all remember the famous Chelsea v Reading game in 2006, where Cech collided with Reading's Stephen Hunt in the first minute, in a collision so brutal it couldn't be seen on TV.

But that wasn't the end, as the Czech was diagnosed with a grade 3 skull fracture and doctors said he could end his career prematurely. Doctors also described the injury as a significant threat to his life. Many thought this was the end for Chelsea's goalkeeper.

However, after a very successful operation, Cech returned four months later and started playing for Chelsea, wearing the famous rugby-style headgear that has made him one of the most famous players in the world.

The skull fracture has healed, but some damage remains on the surface, which is why Cech still wears a helmet and why a new blow could cause more problems, such as permanent concussion and brain damage.

1. David Beckham - asthma

Beckham, one of the best Manchester United and England strikers in history, is famous for leading his team to the semifinals of the 2002 World Cup with a dramatic last-minute free kick. Since then, he has enjoyed a remarkably illustrious career, playing for clubs such as Real Madrid and AC Milan. A skilled finisher and an intelligent central midfielder, he is considered one of the most influential footballers of the 21st century.

Beckham was one of the best when it came to fitness, but a lesser known fact about the former England captain is that he has asthma. In 2009, Beckham was seen using an inhaler while playing with the LA Galaxy in the MLS Cup final against Real Salt Lake. Simon Oliveira, the midfielder's spokesman, mentioned that Beckham has had the disease since childhood.

"David has suffered from this since childhood, but it has obviously not affected his performance."

Beckham has actually never shown any signs of asthma during his career and his diet plays an important role in controlling the asthma.