Histoplasmosis is an infection caused by Histoplasma capsulatum, a type of fungus. You can be exposed to this fungus through contact with bird or bat guano or through contact with infected dust or soil. The infection can spread to your eyes, resulting in ocular histoplasmosis syndrome. Here are three things you need to know about ocular histoplasmosis syndrome.
What are the signs of ocular histoplasmosis syndrome?
If you experience ocular histoplasmosis syndrome, you'll notice changes in your vision. These changes may include distorted vision or blank spots in your vision. You may also notice that objects have a different color or different size depending on which eye you're viewing them with.
Why does histoplasmosis spread to the eyes?
In healthy people, histoplasmosis can either be asymptomatic or lead to respiratory symptoms that are reminiscent of influenza. Once the fungus is in the lungs, it can sometimes spread to the blood and travel to other parts of the body. Doctors refer to this as "hematogenous spread." When this happens, any part of your body that receives blood flow can suffer the effects of Histoplasma capsulatum, including your eyes.
When the fungus reaches the eyes, it can lead to choroidal neovascularization (CNV), though why this happens isn't certain. CNV means that new blood vessels form on your choroid, the layer of vascular tissue inside your eye. These new vessels can leak blood into your eye and are responsible for any visual loss you experience.
In some cases, your eyes may not be affected for years or decades after your original histoplasmosis infection, according to the American Academy of Ophthalmology. It's still not known why these eye symptoms take so long to appear. If you've had histoplasmosis in the past, or if you live in an area where histoplasmosis is common, you're at risk and should see your optometrist regularly so that any eye involvement can be diagnosed early.
How is it treated?
Despite the fungal cause of this condition, antifungal medications have no role in its treatment. Your ophthalmologist will treat the complication that is causing your eye symptoms, CNV. The new blood vessels will be coagulated (burnt) with a laser. This prevents blood from leaking out of the vessels and causing further damage to your vision. CNV may recur after this treatment, so your optometrist will need to examine your eyes regularly to make sure that no new blood vessels are growing in the area. If the condition recurs, it can be re-treated with lasers.
If you think you have ocular histoplasmosis syndrome, see your optometrist right away. Click here for more info about this topic.