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  • Syphilis Eye Infections, While Rare, Are on the Rise

    Reviewed By Purnima S Patel, MD
    Jun. 07, 2023

    Syphilis infections, while uncommon, have increased five-fold over the last two decades. This sexually transmitted disease disproportionately affects gay and bisexual men, as well as people infected with HIV.

    The infection can spread through the body, including to the eyes. If treatment is delayed, ocular syphilis can lead to vision loss.

    Don’t hesitate to call your ophthalmologist as soon as you become concerned. “Early diagnosis and treatment can save sight,” says ophthalmologist and Academy member Purnima Patel, MD.

    Syphilis Risk and Prevention

    How can you tell if someone has syphilis?

    Getting tested is the most reliable way to determine if someone has syphilis. It's not possible to tell if someone has syphilis simply by looking at them. Some people are infected with syphilis and don't know it because they have no signs or symptoms. Doctors usually perform a blood test to determine if someone has syphilis.

    How is syphilis spread?

    Syphilis is spread by skin-to-skin contact with a syphilis sore during sexual intercourse. The infection can also be passed from a pregnant woman to her baby during pregnancy or childbirth. You can't catch syphilis by touching objects such as toilet seats, door handles, bathtubs or clothing.

    What's the best way to avoid catching syphilis?

    Abstaining from sexual intercourse — or only having intercourse with a partner who has tested negative for the disease — are the best ways to prevent syphilis. Condoms can reduce your risk of catching the disease, but you can still get infected if you touch a syphilis sore not covered by the condom.

    When Syphilis Infects the Eye

    Symptoms of ocular syphilis

    Syphilis can show up in the eyes even when there are no other symptoms elsewhere in the body. Most often, inflammation of the front, middle or back of the eye is the first clue that someone has syphilis.

    Ocular syphilis can also cause:

    • eye pain
    • red eyes
    • floating spots in the vision
    • increased sensitivity to light
    • blurry vision

    These symptoms can occur at any stage of syphilis — with or without accompanying skin lesions. They can be easy to miss or confuse with another cause. In fact, syphilis is known as the “great imitator” because it can resemble other health conditions.

    In the latent stage of the disease, which can occur months to a year after the initial infection, there are no symptoms at all. As a result, a person can have syphilis for many years and not realize it until they start developing severe health problems. That’s why it’s essential to see an ophthalmologist without delay if you experience any of these red flags.

    “Chronic inflammation in the eye can cause scarring, permanent loss of vision and can lead to glaucoma and cataract formation,” says Dr. Patel.

    How doctors diagnose syphilis eye infections

    Ocular syphilis is diagnosed with a comprehensive eye exam and a blood test that looks for antibodies produced as a result of the disease. If there’s any suspicion that syphilis has spread to the brain, your doctor may have your spinal fluid tested as well.  

    Ocular syphilis can be cured

    The good news is that syphilis can be treated. The antibiotic penicillin is the standard treatment for ocular syphilis and usually cures the disease.

    If you are allergic to penicillin, your doctor will prescribe a different antibiotic. In certain cases, your ophthalmologist may also prescribe oral and/or topical steroids to control inflammation in the eyes.