Josh Hamilton returned to the lineup on Monday after missing five games with blurred vision and balance issues.

Rangers officials said that Hamilton saw an optometrist and was diagnosed with ocular keratitis, a drying of the cornea caused by too much caffeine and energy drinks.

Hamilton clubbed his league-leading 43rd home run in the fifth inning against the Athletics.

"It's me we're talking about here," he said. "Guys, it's me -- it's Josh. It's going to be something weird."

Hamilton plans to back off the caffeine, which included chocolate after games and an energy drink before games -- not to mention what he was consuming all day long.

"I was loading up on caffeine, and I'm out there in the bright lights," he said. "I can't control my eyes. They are stuck."