Presumed Ocular Histoplasmosis Syndrome (POHS): Symptoms, Causes, Treatment

What are the symptoms of presumed ocular histoplasmosis syndrome?

Presumed ocular histoplasmosis syndrome (POHS) is a condition caused by the fungal infection Histoplasma capsulatum, typically resulting from a previous histoplasmosis infection. Symptoms of POHS include:

• Visual Disturbances: Blurred vision, loss of vision, or difficulty seeing clearly, often due to changes in the retina.
• Floaters: Seeing small spots or lines floating in the field of vision.
• Central Vision Loss: Difficulty with activities requiring fine detail, like reading or recognizing faces, due to damage to the central part of the retina (macula).
• Scotomas: Dark or empty spots in the central vision.
• Distorted Vision: Straight lines may appear wavy or distorted due to retinal damage.

These symptoms typically arise from changes or damage to the retina and choroid, and they may develop gradually over time. If you experience any of these symptoms, it’s important to consult an eye specialist for proper evaluation and management.

What are the causes of presumed ocular histoplasmosis syndrome?

Presumed ocular histoplasmosis syndrome (POHS) is caused by a fungal infection known as histoplasmosis, which is typically contracted from inhaling spores of the fungus Histoplasma capsulatum. The main causes and contributing factors include:

• Histoplasmosis Infection: The primary cause is a prior infection with Histoplasma capsulatum. This fungus is commonly found in soil contaminated with bird or bat droppings. Although many people with histoplasmosis experience no symptoms or mild flu-like symptoms, the infection can affect the eyes later in life.
• Immune Response: The body’s immune system may react to the fungal infection in the eyes, leading to inflammation and damage to the retina and choroid (the layer of blood vessels beneath the retina).
• Genetic Factors: Some individuals may be genetically predisposed to develop POHS after exposure to the fungus.
• Environmental Exposure: Living in or traveling to areas where histoplasmosis is common can increase the risk of developing POHS.

The exact mechanism of how the infection leads to ocular symptoms is not fully understood, but it is believed that the immune response to the fungus plays a significant role in causing damage to the eye tissues.

What is the treatment for presumed ocular histoplasmosis syndrome?

The treatment for presumed ocular histoplasmosis syndrome (POHS) focuses on managing symptoms and preventing vision loss, as there is no cure for the underlying fungal infection. The main approaches to treatment include:

• Regular Monitoring: Frequent eye exams by an ophthalmologist to monitor the condition and detect any changes in vision or retinal health.
• Anti-VEGF Therapy: Medications that inhibit vascular endothelial growth factor (VEGF) can be used to reduce abnormal blood vessel growth and fluid leakage in the retina. These are administered through injections into the eye and can help manage vision loss.
• Laser Therapy: In some cases, laser treatment may be used to target and destroy abnormal blood vessels or lesions in the retina that are contributing to vision problems.
• Corticosteroids: These may be prescribed to reduce inflammation and swelling in the retina, though their use is generally reserved for specific situations where inflammation is significant.
• Vision Aids: Low vision aids and rehabilitation services can help individuals adapt to vision changes and improve their quality of life.
• Lifestyle Modifications: Protecting the eyes from excessive sunlight and maintaining a healthy diet can support overall eye health.

It’s important for individuals with POHS to work closely with their eye specialist to determine the best treatment plan based on their specific symptoms and condition.