Prevalence of ocular lesions in cats newly diagnosed with histoplasmosis: 55 cases (2015-2022).

Objective: To describe the prevalence of ocular lesions in cats with newly diagnosed histoplasmosis.

Animals: 55 client-owned domestic cats.

Procedures: As part of this prospective case series, cats diagnosed with histoplasmosis between the years 2015 and 2020 underwent complete ophthalmic examinations by a board-certified veterinary ophthalmologist prior to the initiation of antifungal treatment. Histoplasmosis was diagnosed by consistent clinical findings and identification of Histoplasma yeast on pathology or by the use of a commercially available enzyme immunoassay to detect Histoplasma antigen in urine.

Results: Of the 55 cats, 45 (82%; 95% CI, 72% to 92%) had signs of active anterior, posterior, or panuveitis. The most common lesions were identified in the posterior portion of the globe and included chorioretinitis and partial retinal detachments (44/55 [80%; 95% CI, 69% to 90%] cats).

Clinical Relevance: Detailed ophthalmic examinations should be performed on all cats with diagnosed or suspected histoplasmosis, as ocular involvement and subsequent vision loss are common.