The 32-year-old Scot shot a four-under-par 68 in Shanghai and is four shots behind early leader Sergio Garcia.
Ramsay was forced to miss events in October due to blurred vision.
"It's just nice to be back playing," he told BBC Sport. "My eye is much better, although I'm still on drops for another couple of weeks."
The Aberdonian returned for last week's Turkish Airlines Open, finishing in a tie for 56th.
But he is well placed this time after a good opening round in China as he looks to finish the season on the good form he showed at the beginning of the year.
"I had a few weeks off and my game feels good," explained the three-time winner on the European Tour.
"I had a thing called anterior uveitis, which was causing inflammation in my left eye. The only thing to treat it is steroids but it stops your eye from focusing, so everything is blurred.
"For a while I really struggled with reading and trying to focus on the ball was really tough; seeing the target was near-impossible.
"It was a strange feeling since my eyes were pretty much 20-20 beforehand.
"I've got nothing to lose over the next two weeks, so I'll go out and try and push for a high finish."
Richie Ramsay is pleased to be over the worst of his eye infection as he ended the first day of the BMW Masters in a share of ninth place.