BOSTON -- It can start with redness and irritation in the eye -- even conjunctivitis -- but for some, it can turn to a chronic, painful inflammation.

NewsCenter 5's Liz Brunner reported Wednesday that the condition is called uveitis, and a tiny implant, recently FDA approved, is helping some of those with the most severe form of the disease.

Mercedes Lopez was a happy factory machine operator until her left eye became red, painful and her vision started to go.

"I lost my job, depressed. Sometimes, I can't drive anymore. I need people who'll help me. I want to be strong, but it is not enough," Lopez said.

Lopez has uveitis -- inflammation of the uvea. It can be caused by a virus, an injury to the eye, or be a symptom of another disease such as arthritis, gastrointestinal problems or lupus.

Now, a new microtechnology treatment -- a tiny implant -- is giving patients with chronic uveitis hope. Retisert is surgically embedded in the back of the eye, and it delivers tiny amounts of steroid medication over two and a half years.

"It clearly represents an impasse in what we had up until this point for those patients who have inflammation in the back of the eye, where it's tough to get medicine there," Massachusetts Eye Research and Surgery Institute's Dr. Stephen Foster said.

Phase 2 studies showed 80 percent of those who had the device stabilized or improved their vision after 34 weeks, and it reduced the need for other treatments, such as steroid injections, from 63 percent to 5 percent.

But it does have major side effects. Foster said everyone who gets a Retisert will develop a cataract.

"About one-third of the patients who get a Retisert have glaucoma that is significant enough that it cannot be controlled with medicine," Foster said.

But, for the 175,000 people with uveitis, those with the most severe disease now have a new option.

"I believe this could work for me," Lopez said.

The Retisert implant costs about $18,000, but so far, Foster said insurance has picked up most of the cost.