LOS ANGELES (CBSLA.com/AP) — Health officials warned doctors Tuesday to be on on the lookout for patients reporting unusual vision problems after clusters of syphilis that cause blindness have been reported on the West Coast.

Two possible cases of ocular syphilis are under investigation in Los Angeles County, but “no cluster [of cases] has been locally identified, according to the county Department of Public Health.

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Officials say the sexually transmitted disease mostly occurs among men who have sex with men, the Associated Press reported.

In December and January, health officials in Washington state reported six people diagnosed with ocular syphilis— including two who have gone blind — AIDS Healthcare Foundation (AHF) spokesperson Ged Kenslea.

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Another seven cases of ocular syphilis have been reported in San Francisco, five of which involved men who have sex with men (MSM) and six who were HIV-infected, Kenslea said.

Symptoms of ocular syphilis include blurred vision, eye pain and seeing floating spots.

A recent CDC STD surveillance report found that California’s syphilis rate was second in the U.S. only to Georgia, according to AHF.

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