Ocular abnormalities in the Icelandic horse with a focus on equine recurrent uveitis: 112 Icelandic horses living in Denmark and 26 Icelandic horses living in the United States.

Abstract

PURPOSE: To describe the most common ocular abnormalities in the Icelandic horse with focus on equine recurrent uveitis (ERU) and association between ocular abnormalities and summer eczema and coat colors. METHODS: A descriptive cross-sectional study. A complete physical and ophthalmic examination as well as measurement of serum titers for Leptospira serovariants was performed on Icelandic horses from Denmark (DK) and the United States (USA). RESULTS: One hundred and twelve Icelandic horses living in DK and 26 Icelandic horses living in the United States were included in this study (total of 138&#xa0;horses, 274 eyes). The three most common ocular abnormalities were follicular conjunctivitis (55.8%, 153/274 eyes), cataracts (27.4%, 75/274 eyes), and multifocal chorioretinopathy ("bullet holes"; 19%, 52/274 eyes). The prevalence for ERU among Icelandic horses aged "eight years and older" was 8% (6/75&#xa0;horses). The "insidious ERU" type was found in 83% of the ERU cohort (5/6&#xa0;horses), while "classic ERU" was found in 17% (1/6&#xa0;horses). A correlation between ERU and cataracts was found in the population (p&#xa0;<&#xa0;.01). Leptospiral serology results were not associated with ERU in either DK or US-Icelandic horses (p&#xa0;=&#xa0;1.00, p&#xa0;=&#xa0;1.00, respectively). ERU was not associated with summer eczema (p&#xa0;=&#xa0;.49), and no coat colors were associated with the ocular abnormalities found in the Icelandic horse (all p-values&#xa0;>&#xa0;.05). CONCLUSION: Follicular conjunctivitis, cataracts, and multifocal chorioretinopathy were the three most common ocular abnormalities findings. Icelandic horses who were 8&#xa0;years or older had an 8% prevalence for ERU. Summer eczema and coat color were not associated with evidence of ERU or other ocular abnormalities.