Ocular histoplasmosis syndrome

Ocular histoplasmosis syndrome (OHS) is a chorioretinal disorder with a distinct fundus appearance that is commonly found in regions endemic for Histoplasma capsulatum. Choroidal neovascularization (CNV) secondary to OHS is considered one of the principal causes of central vision loss among young adults in endemic areas. Although there is no consensus regarding its pathogenesis, evidence points to Histoplasma capsulatum as the most probable etiology. Once considered an intractable hemorrhagic maculopathy, CNVs are now treatable. Extrafoveal CNVs are successfully treated with laser photocoagulation. Subfoveal and juxtafoveal CNVs are managed with anti-vascular endothelial growth factor therapy, photodynamic therapy, or a combination of both. Modern imaging technologies such as spectral-domain optical coherence tomography have improved our diagnostic abilities, making it easier to monitor disease activity and CNV regression. We review the epidemiology, pathogenesis, clinical manifestations, differential diagnosis, and current treatment of this disease.