Liverpool chief executive Rick Parry has moved to try to ease concerns over Mohamed Sissoko after a Portuguese medic suggested his vision could be severely compromised.

Sissoko flew back from Portugal yesterday following an overnight stay in hospital after a kick in the head by Brazilian midfielder Beto in 1-0 Champions League defeat to Benfica forced him off in the first half.

The Mali international suffered damage to the retina in his right eye and is currently being cared for by specialists in London.

Parry said it was too early to say what the extent of the problem was even though Joao Paco, clinical director of the hospital which treated Sissoko in Lisbon, said his vision could be compromised by up to 80 per cent.

"We don’t want to sound too pessimistic because it’s too early to tell," Parry told the club’s website. "What Momo needs right now is our support and the best care he can get.

"His right eye is closed down and it’s been difficult to assess the damage because of the swelling and bleeding.

"However, it’s too early to jump to conclusions. Obviously this is a very traumatic time for Momo and the club is in constant contact with his family and representatives. It’s a very nasty injury.

"He’s now in London being treated by the best specialists in the country."

The 21-year-old Sissoko, complaining of blurred vision, was left behind in Lisbon on Tuesday night while the team returned home.

Paco had earlier said: "The prognosis is guarded but vision is going to be compromised on the right side, it may be 80 or 20 per cent, but we can’t say yet.

"He suffered trauma with bruising to the eye but there was no apparent destruction of the structure."