According to ABC News, yes:
But now, as American astronauts spend more and more time in space, they've noticed they're returning to Earth with a surprising malady: They cannot focus their eyes properly after they come home, and for some the problem seems permanent.
A fifth of the astronauts tested showed a flattening of the rear of the eyeball, affecting their ability to focus their eyes. A third showed expansion of the space surrounding the optic nerve that's normally filled with cerebral spinal fluid.
Also according to CNN:
In the past few years, about half of the astronauts aboard the international space station have developed an increasing pressure inside their heads, an intracranial pressure that reshapes their optic nerve, causing a significant shift in the eyesight of male astronauts. Doctors call it papilledema.
Interestingly, only male passengers seem to have been affected:
Female space travelers have not been affected.
Barratt is one of 10 male astronauts, all older than 45, who have not recovered. Barratt returned from a six-month stint aboard the station in October 2009 and has experienced a profound change in his sight.
He used to be nearsighted. But now, the space veteran says he’s eagle-eyed at long distance but needs glasses for reading. There is no treatment and no answers as to why female space flyers are not affected.
Also Aviation Week:
Nineteen ISS astronauts have developed symptoms of impaired vision since the ailment was first recognized in 2005, according to Dr. Christian Otto, a Universities Space Research Association remote medicine specialist who serves as the principal investigator for the NASA-sponsored Prospective Observational Study of Ocular Health.
The study, ultimately involving a dozen closely followed international astronauts, will search for a link between the blurred vision and the long observed shift of fluid from the lower torso to the chests and heads of fliers as they adjust to weightlessness. The fluid shift now appears to affect the eyes as well as the cardiovascular and central nervous systems.
With this in mind, I think we can say that the reduced gravity affects astronaut's vision - not the lack of objects for them to focus on.