Abstract
Background:
Uveitis is a common ophthalmic diagnosis in cats, that can lead to discomfort and loss of vision. Identification of non-idiopathic cases facilitates treatment and could reduce morbidity associated with this condition.
Aim:
To evaluate etiologies of non-traumatic uveitis in the UK, to compare diagnostic features between idiopathic cases and those with an established underlying etiology, and to investigate the association of clinical signs and abnormal diagnostic findings with a confirmed etiology.
Methods:
Records of cats diagnosed with uveitis at a UK referral center between August 2009 and April 2018 were retrospectively reviewed, excluding traumatic (and reflex) cases. Cases were categorized based on whether an underlying etiology had been established in cases with a confirmed etiology, idiopathic and inconclusive cases. All cases had a minimum of 12-month follow-up unless an underlying etiology had been established. Population characteristics, clinical signs, diagnostic investigation features and results were reported.
Results:
72 cases of uveitis were included, of which male cats and domestic breeds were overrepresented. An underlying etiology was determined in 23.6% of cases: 9.7% had infectious diseases, 5.6% systemic neoplasia, 4.2% primary ocular neoplasia and 4.2% metabolic disease. Idiopathic uveitis comprised 37.5% of cases, and the remaining 38.9% were inconclusive, of which 35.7% died or were euthanized within the follow-up period. Among the study population no significant age difference was found between cats with idiopathic disease or confirmed etiology. Unilateral disease was reported in 56.9% of cases and was not different across the idiopathic cases and confirmed etiology groups. The most common ophthalmic clinical sign was aqueous flare, followed by keratic precipitates and hypotony. Iris color change (P=0.015) and the presence of an intraocular mass (P=0.025) were associated with an underlying etiology.
Conclusion:
Idiopathic uveitis was found to be the most common diagnosis in this study population. However, a similar proportion of cases had possible underlying etiologies as a high proportion manifested systemic disease within the follow-up time. An underlying etiology could be established only in a quarter of cases. Further studies are required to standardize the investigations required when assessing cats with uveitis to minimize patient morbidity.

Key words: Cat, Eyes, Hypertension, Aqueous flare, Inflammation