David de Gea's erratic first season at Manchester United has taken place with the talented but error-prone goalkeeper suffering from an eyesight problem that may necessitate laser surgery at the end of the season.

De Gea, dropped from United's past three matches after making a succession of mistakes, is long-sighted and plays in contact lenses. United employ a full-time optometrist, based at their training ground, and the Spaniard has been recommended for treatment to restore his sight to normal as he tries to cut out the mistakes that have cost him his place as Sir Alex Ferguson's first-choice goalkeeper.

Having worn glasses for most of his life, De Gea was going to have laser surgery last March when he was at Atlético Madrid. At the time, however, the Atlético medical staff told him to wait at least another year because he needed a stable prescription.

United were aware of the issue when they signed him for £18.3m in the summer. De Gea has had regular check-ups since replacing Edwin van der Sar and held off the challenge of Anders Lindegaard until one mistake too many in the 3-2 home defeat against Blackburn Rovers on New Year's Eve.

De Gea has been at fault, to different degrees, for as many as six to nine goals in his first five months in the team and, though there have been times when his goalkeeping has been exceptional, his first season in England has been a difficult one. Whether there is any link to his vision is not clear, but wearers of contact lenses often find their eyesight is strained when watching football under artificial light, and the priority at Old Trafford is to make sure it is not even potentially a factor.

United still have high aspirations that De Gea, at 21, can demonstrate he was worth the money and become a great goalkeeper for the club.

The hope is that he can be booked in for laser treatment in June, when he could take advantage of the summer break to have the four-day period of rest that is advised. He is then expected to be selected for Spain's Olympics squad if, as expected, he misses out on Euro 2012 behind Iker Casillas, José Reina and Victor Valdés.