BOSTON -- The Massachusetts Eye and Ear Infirmary is offering a word of caution for the nation's 30 million contact lens wearers. Be very careful how you clean your lenses.

NewsCenter 5s Heather Unruh reported Wednesday that one local man ended up with amoebas in his eye that nearly cost him his vision.

"It got to the point I couldn't keep my eye opened. It was becoming very sensitive to light," James Carney said.

A year and a half ago, the Sharon resident was just starting to enjoy his retirement when his right eye suddenly became very red and painful while on vacation in Florida.

A contact lens wearer, he didn't know that he had contracted a very rare and extremely serious organism called acanthamoeba. Parasites had invaded his eye.

Carney said, "I probably had several hundred thousand if not a million of them (parasites) in my cornea, the colored part of my eye."

After three major surgeries at Massachusetts Eye and Ear Infirmary, including two cornea transplants, Carney's vision in his right eye is still blurry. Doctors said they think this rare but extremely serious condition resulted when infected water got on his contact lens.

"It's caused by an organism that's found everywhere in water and air filters, things like that," said Dr. Kathryn Colby of Massachusetts Eye and Ear. She said the Centers for Disease Control have investigated 138 cases of this outbreak in recent times, but it's not new.

"When this organism was first epidemic in the late 1970s and early 1980s, it was traced to people using homemade saline for contact lenses," she said.

And for the most part, Colby said it is contact lens wearers who are vulnerable because so-called multi-purpose contact lens cleaning solutions are not doing a good enough job.

The safest, easiest and most comfortable way to wear contact lenses according to Colby is to wear daily disposable ones. She said to open up a fresh package in the morning and throw it away at the end of the day.

She also suggested that if you do need to wear the more long-lasting lenses, you should clean them with a hydrogen peroxide solution. It's less convenient, but she said it does a better job at keeping parasites out of your eyes.