Ocular histoplasmosis syndrome (OHS)

OHS, or Ocular histoplasmosis syndrome, is an eye condition affecting people who have a lung infection known as histoplasmosis. Histoplasmosis, which affects the lungs, can also spread to your eyes, causing vision loss.

Most people who develop histoplasmosis aren’t aware they have the infection. If you live in an area where histoplasmosis affects many people, ensure you consult your eye doctor to get checked for OHS.

Symptoms of OHS

OHS does not usually cause symptoms in the early stages, but over time, the following may occur:

• Blind spots in vision
• Straight lines looking wavy or crooked

Causes of OHS

Histoplasmosis is a lung infection that causes OHS. This lung infection occurs when people breathe in spores from a fungus called Histoplasma capsulatum. This fungus is present in the soil that has bat or bird dropping. Spores from this fungus can enter the air when someone moves the soil around, like while ploughing a field or sweeping chicken droppings.

Experts believe that people develop OHS when the spores spread from their lungs to the eye, and it can leave scars on the back of the eyes. The scars are often harmless, but sometimes, they result in abnormal blood vessels growing in the eye, which causes vision loss.

Can I have OHS?

Anyone can have histoplasmosis and OHS if they have been in an area with histoplasma fungus. Many people who live in areas where histoplasma fungus is present do not know they may have histoplasmosis.

Some groups are more susceptible to histoplasmosis and OHS. They include:

• Adults aged 55 and above
• Babies
• People with a weak immune system, such as people with HIV/AIDs or those taking certain medicines

OHS is not contagious, so you can’t spread it to other people if you have it.

How can my eye doctor diagnose OHS?

Your eye doctor will carry out a dilated eye exam to check if you have OHS. This test looks for:

• Swelling in the retina
• Scars in the back of the eye

If the doctor finds abnormal blood vessels, blood or fluid during your dilated eye exam, they may perform an optical coherence tomography (OCT) to check for abnormal blood vessels and swelling. You may also need another test called fluorescein angiography. This test allows your optician to see pictures of blood vessels in your retina.

Treatment for OHS

Two effective treatments are available for OHS. These are outpatient procedures, so you won’t need to be in the hospital overnight.

• Injections Medicines like anti-VEGF drugs can prevent OHS from becoming worse and improve vision.
• Laser surgery Your eye doctor can use lasers to prevent abnormal blood vessels from OHS from growing, bleeding or leaking.

If you’ve experienced serious vision loss from OHS, consult your doctor about a referral to a low-vision specialist. This specialist can help you learn to live with your vision loss.

You can visit Optimal Vision for an eye exam with our experienced eye doctor. Contact us now at 020 7183 3725 to schedule a routine eye examination.