Uveitis is characterized not only by inflammation of the uveal tract but also involves the retina and vitreous either directly or indirectly and is prevalent all over the world. [1] It predominantly affects patients in the working-age group, mainly 20-60 years.[2] The average annual incidence of Uveitis is estimated to be approximately 14–17 per 1,00,000 and increases to a peak in the 20–50 age group, after which it declines. [3-6] Geographically, the prevalence of Uveitis varies worldwide and is estimated to be 730 per 100 000 in India.[7] Uveitis can cause devastating visual loss, and in the developed countries, it's the fifth commonest cause of visual loss.

It accounts for about 10–15% of the cases of total blindness according to WHO definition and up to 20% of legal blindness. [3,1] Uveitis may be induced by infection, autoimmune disease, trauma or malignancy.[2] Standardization of Uveitis Nomenclature (SUN) has divided Uveitis into four types – anterior, intermediate, posterior and panuveitis, according to their anatomical location.[8] The pattern of Uveitis is mainly influenced by many factors, including genetic, ethnic, geographic distribution, environmental factors, diagnostic criteria and referral patterns.[9] The pattern, diagnosis, pathogenesis and presentations of Uveitis vary due to the appearance of newer uveitic entities and even with improved and advanced diagnostic techniques.

However, in approximately 30–40% of newly diagnosed uveitis patients, it's still challenging to reach a definite diagnosis. [10-13] The results of various epidemiological studies on Uveitis in different geographical regions provide relevant clinical and research applications. Several studies have been published on the pattern of Uveitis in various geographic areas from Western and Asian countries that show similarities and differences in epidemiological profiles and aetiologies of Uveitis. [3-7,9-14,16-25] Hence, we plan a study to identify the clinical pattern of Uveitis and evaluation of the etiological factors in the regional institute in Punjab and its surrounding areas.

Study setting: Department of ophthalmology in a regional eye institute of North India

Study duration: Jul 2012 to Jan 2014

The most common (30% cases) age group was 41-50 years and included 28% males and 32.55% females. Uniocular involvement was observed in 68%, whereas 32% of cases showed bilateral involvement. Acute Uveitis was diagnosed in 32% of patients, and chronic Uveitis in 68% of cases. According to anatomical classification, the most common type of Uveitis was anterior Uveitis (83%),

The most common specific diagnosis for anterior Uveitis was ankylosing spondylitis and herpes zoster in 6 patients each (7.23% of anterior uveitis patients), followed by Tuberculosis (3 out of 83 patients). [Table1] In posterior Uveitis, the most common specific diagnosis was Tuberculosis (28.57% of posterior uveitis patients). [Table1] In panuveitis, the particular diagnosis could be established in 4 patients, and in intermediate Uveitis, only one patient was diagnosed having HIV. [ Table1]

Our study provides information about the pattern of Uveitis in a regional eye institute and identifies the uveitic entities typical for this region. Adults are most often affected with Uveitis in both the developed and developing world. [16,18] The previous clinical studies showed mean age between 35 and 45years [16-18], and approximately

In our study, anterior Uveitis (83%) was the predominant anatomical type of Uveitis. It was higher than that reported in other studies. [19-23, Table 2] In contrast, Shirahama et al. [23] reported

In our study, the most frequent entity diagnosed was idiopathic anterior Uveitis (64% of total cases) which was similar to a study conducted in Southern China by Zheng Y et al. [14], who found 65% of anterior uveitis cases to be idiopathic. Our study observed ankylosing spondylitis and Herpes zoster (6% each) as the most common underlying cause for non-infective anterior Uveitis, similar to studies by Dipankar Das et al. [22], who found 23.44% of cases with ankylosing spondylitis and Singh et al. [21] found 8.8% cases with ankylosing spondylitis as the most frequent non-infective cause for

In our study, no aetiological cause for intermediate Uveitis was found. The results were similar to other studies that found that various systemic disorders, including sarcoidosis, TB and multiple sclerosis, are associated with intermediate Uveitis. [16-18] We found sarcoidosis as an infective cause for intermediate Uveitis in 1% of cases. (Table3) The leading cause for posterior Uveitis was also idiopathic (4%) in our study, consistent with studies by R Singh et al. [21] and Zheng Y et al. [24]. In contrast, other studies [19,20,22] found toxoplasmosis as the leading cause.

Das et al. found 40.21% cases of toxoplasmosis as a causative agent in posterior Uveitis. [22, Table 3] Another infective cause for posterior Uveitis was Tuberculosis in 2% of patients in our study (Table 3), comparable to other studies. [19,21,22] The incidence of HIV retinopathy was 1% in our study compared to 0.55% (2 out of 366) cases reported by Biswas et al. [25]. Panuveitis is relatively uncommon in the Western region. [17,18,26] We found no aetiological cause in 33.33% (2 out of 6 cases, Table 1), which was consistent (30 out of 472) with a study conducted in Tunisia.[20] Other infective causes for panuveitis were Tuberculosis, HIV, sarcoidosis and endophthalmitis (1% each) in our study.

Tuberculosis was found to be one of the causative factors in panuveitis in various studies. [19-21,24, Table 3] However, Mercanti et al. [19] and Das D et al. [22] found VKH as a common infective entity in panuveitis, and Khairallah et al. [20] and R Singh [21] found VKH as the second common infective cause for panuveitis. (Table3) Sarcoidosis was also one of the causes for panuveitis in our study and other compared studies in Table 3. [19,21,22]. Our study also found metastatic endophthalmitis as a cause for panuveitis, similar to findings in a study by Zheng Y et al. [24] In.

In our study, the most common cause for Uveitis was idiopathic in all forms of Uveitis which was inconsistent with most of the studies conducted in different parts of the world. [19-22,24] There were differences in respect to the aetiological distribution of Uveitis according to the regional and ethnic variation throughout the world [19-23] and also between secondary, tertiary and regional institutes in India itself. [21,22,25] Small sample size and the referral bias amongst the cases may be limitations in our study, but consistent results with other extensive studies were encouraging.