Cristiano Ronaldo is one of the most popular soccer players in the world, which is one reason why he, along with fellow international star Lionel Messi, were the targets of laser pointers from fans in recent matches between Real Madrid and Barcelona.

According to Yahoo Sports, the trend of fans using laser pointers has taken hold in Europe and many sports officials and medical professionals are worried about it moving to the United States. Doctors have also expressed concern about long-term damage that it could cause and that injuries can be a result of the fan behavior.

During matches last week both Cristiano Ronaldo and Lionel Messi were targeted by opposing fans using the laser pointers in the hopes of throwing them both off their world-class game. The pointers could be seen on the faces of players and doctors have said that sometimes the pointers can cause blindness.

The report talks about the rare use of laser pointers at American sporting events, including last year at a St. Louis Cardinals' game at Busch Stadium. Dr. Robert Josephburg, an ophthalmologist and retina specialist at the Westchester Medical Center in Valhalla, N.Y., has spoken to government officials about the use of laser pointers and said that permanent damage could come from using the pointers on players.

"I have been stunned at the power of these things," Josephburg said in a telephone interview with Yahoo! Sports on Monday. "We are talking about serious damage even if someone is only exposed to it for a few seconds.

The football stars were luckily not seriously injured, but both were frustrated with the laser pointers. Ronaldo was targeted early in a 3-1 victory in a Spanish Cup clash in Barcelona, although he was able to get through it. Following the move on Ronaldo, Messi was then targeted over the weekend at Santiago Bernabeu stadium.

"If I was a ball player I would be terrified. I only hope Congress acts on this before some real harm is done. The retina is very sensitive and is not made to cope with light of that intensity. If shined for even a few seconds into someone's eyes different symptoms can occur, temporary blindness, blurry vision, spotty vision, the sight may not even fully return," Josephburg said

One of the biggest issues for soccer officials is locating the laser pointers, as it can be very hard to find exactly where it is coming from among many fans. Many pointers have long-range capabilities and although many stadiums prevent people from taking them in, they are small and can easily be concealed.

"If you were in the last row at a football stadium you could aim at someone on the field, easily," added Josephburg.

New pens have longer ranges than older ones and are mainly meant for use in the construction industry and medical profession. Fans can buy them on the internet and the new ones that come with a green light, like the ones used on Messi and Ronaldo, are much stronger than previous models.

In the United States, a 17-year-old boy was arrested at a San Francisco Giants game for using one on pitcher Shane Loux, while the fan at the Cardinals game was spotted by manager Mike Matheny

"You can clearly notice it on telecasts, especially games coming from Spain," said Aidan Magee, a journalist and broadcaster with Sky Sports in the United Kingdom. "It is obviously not ideal when you have anyone being endangered in this way, especially two of the most valuable and precious commodities in soccer like Messi and Ronaldo."

Magee said European officials are taking the laser pointer issue seriously and are taking steps to help players like Ronaldo and Messi in the future.