Epidemiological insights into Childhood vernal keratoconjunctivitis in India: Unravelling clinical presentation and environmental influences - The EPIC VKC study - Fourth report of the ICMR EYE SEE study group.

Purpose: To study the epidemiology and clinical presentation of allergic eye diseases (AEDs) and Vernal Keratoconjunctivitis (VKC).

Methods: A cross-sectional- cum-cohort study was conducted in rural and urban areas in different geographical locations (plains, hilly, high-altitude and coastal) in India. Children (5-15 years) were included, information on exposure to environmental factors gathered, participants screened for AED and VKC on torch light, followed by a comprehensive eye examination. Cases were compared with controls. Physical environmental parameters (ultraviolet A/UVA flux) were also measured.

Results: In all, 8231 participants were screened, 410 had AED (56 % males, mean age 13.7 ± 4.5 years) and 92 had VKC (66.3 % males, mean age 14.5 ± 4.4 years). The likelihood of AED was higher for ages 11-16 years (OR 1.51, p < 0.03, urban areas (OR 1.44, p = 0.049), poor socioeconomic status (OR 1.5, p = 0.007), exposure to smoke of incense sticks (OR 1.88, p = 0.001), bright sunlight (OR 3.56, p < 0.0001), dust/pollution exposure (OR 2.49, p = 0.001) and winter season (OR 2.73, p = 0.003). AEDs were less likely in coastal areas (OR 0.14, p < 0.001). Exacerbating influences for VKC were windy weather (OR 4.35, p = 0.01) and spring season (OR 13.45, p = 0.001). VKC prevalence was higher in rural (69.6 %) than urban areas (30.4 %) (p = 0.03); with 11.9 % visual impairment. Palpebral VKC was the commonest type (82.6 %). Maximum UVA mean flux was noted in plains.

Conclusion: The prevalence of AEDs and VKC in the community is 4.98 (95%CI: 4.51-5.45)% and 1.11 (95%CI: 0.89-1.34)%, respectively. AEDs have association with pollution or dust exposure and winter season. Palpebral VKC is the commonest clinical form of VKC.