SURPRISE, Ariz. -- Tony Pena knew something had to be done about his vision.

The Royals' infielder was having trouble picking up the spin on breaking pitches and tracking the fastball.

"I didn't have the same depth perception," Pena said.

Even out in the infield, he noticed.

"When I was playing shortstop, I couldn't see the catcher's signs," said Pena.

It was about two years ago that doctors had Pena try soft contact lenses. That didn't work very well.

"I would try them but they would just burn my eyes too much," he said.

Last season Pena switched to a pair of glasses with large lenses that looked more like goggles. That helped a bit. But, three days after the season, he underwent Lasik surgery.

Pena won't go so far as to say his vision problems caused the hitting woes that cost him his regular shortstop job last season. He's not looking for excuses and he just doesn't know.

"I think it probably could have had a lot to do with it," said manager Trey Hillman.

Mike Aviles came in from Triple-A Omaha at the end of May when Pena was hitting just .160, and within a week, he took over at shortstop. Now Pena will be hard-pressed to make this year's roster.

But Hillman noticed a positive turn for Pena during an intrasquad game on Sunday.

"I saw him have a real good at-bat," Hillman said. "Two things happened, he didn't swing at a two-strike breaking ball that wasn't too far off the plate, and on the two-strike count, he got a base hit to the right side."

Pena is certain his eyes are better.

"Definitely. I went into winter ball just to see how everything worked out, and it was good," he said.

In 46 games for Aguilas in the Dominican Winter League, Pena batted .275, popped a couple of homers and had 18 RBIs. His on-base percentage was .347.

His improved vision has given him more confidence as the Cactus League schedule is about to begin.

"It has, especially coming out of winter ball where it felt good and I was seeing the ball pretty good, so I'm looking forward to it," Pena said.

Hillman said that Pena will not be buried on the bench during the Cactus League games.

"It's not like, 'OK, Tony had a bad year last year and we're going to sit him over here and play him when we can,'" Hillman said. "He's prioritized to get playing time so we can see what we've got."

Pena could get some extra time early in March while Aviles is away playing for Puerto Rico in the World Baseball Classic.

He finished at .169 last season, after batting .267 as the regular in 2007, so the Royals will be watching to determine just how much the eye surgery has helped.

"I always go back to rule No. 1 and that's trust what the players say, and T.J. said, with this surgery, his depth perception is a lot better," Hillman said. "It's awfully difficult to hit a baseball anyhow, but if your depth perception is screwed up and your vision's a little bit off then that's going to complicate it quite a bit."