Purpose
The study aims to describe and analyze the clinical characteristics and etiologic causes of intermediate uveitis (IU) patients seen by a tertiary eye care center in Singapore over 8 years.
Methods
This was a retrospective analysis of all 66 consecutive cases of IU that presented to the Uveitis clinic, out of a total of 1168 uveitis patients, between 2004-2011. Data collected included demographics, clinical and laboratory findings, and complications. Diagnoses for specific ocular entities or systemic disease associations were based on standardized clinical history, systemic review, complete ophthalmological examination and laboratory investigations. Further ancillary investigations were performed where necessary. Cases were classified as idiopathic when a specific etiology was not identified.
Results
There was a male:female ratio of 1:1.2, and the disease was bilateral in 37 patients (56.1%). The median age of diagnosis was 40 years, with majority of the patients in the age group of 41-60 years (n=24, 36.4%). The majority was Chinese (n=38, 57.6%), followed by Indians (n=12, 18.2%) and Malays (n=11, 16.7%). The ethnicity distribution was dissimilar to our ethnic distribution in Singapore (p<0.001). Most were idiopathic (n=39, 59.1%) in etiology, followed by tuberculosis (TB) (n=10, 15.2%). Ocular complications developed in 21 patients (31.8%), with cystoid macular edema (CME) being the commonest (n=19, 28.8%), followed by severe vitritis (n=6, 9.1%). TB-associated IU was associated with complication of severe vitritis (p <0.001). There was a downward trend for the proportion of IU patients over the total uveitis patients (p=0.021), with Spearman’s rho of -0.786.
Conclusions
Our results suggest a downward trend for the proportion of IU over the total uveitis patients. However, TB-associated IU was of higher prevalence compared to less endemic areas, emphasizing the need for increased TB surveillance. A high index of suspicion for TB-associated IU is required in patients with severe vitritis. Comparisons with other countries revealed disparities in the IU etiologies, indicating possible genetic and geographical differences. Prevalence of autoimmune etiologies of IU is less compared to the western population. Our study showed an increased incidence of IU in the Indian population, suggesting a probable predisposition of the Singapore local Indian population for IU.
Keywords: 463 clinical (human) or epidemiologic studies: prevalence/incidence •
462 clinical (human) or epidemiologic studies: outcomes/complications •
746 uveitis-clinical/animal model