Objectives To identify the risk factors for PolyA development in NIU patients and determine if PolyA may be related to worse visual outcomes.Methods We investigated immune-mediated diseases in a cross-sectional study of 218 consecutive NIU patients. Univariate logistic regression and Kaplan-Meier analysis with Cox regression were performed for losing two lines of vision on the Snellen between patients with PolyA and without PolyA.Results PolyA was present in 45.9% of NIU patients. Median age at diagnosis was 44 (IQR 24–57) years, with a predominance of women (PolyA 71% vs. without PolyA 68%). Uveitis etiology shows a difference between patients with PolyA and without PolyA (autoimmune disease represents 54% PolyA vs. 0.8% without PolyA (P < 0.001)). Clinical features of PolyA uveitis included mainly bilateral, anterior, and non-granulomatous, with insidious onset and a recurrent course. The most common immunomarkers were HLA-B27 and antinuclear antibodies (ANAs), that was also significantly more frequent in PolyA patients (25% vs. 9.3% (P = 0.002)). Risk factors for developing PolyA included ages 30–64, anterior uveitis, positive ANAs, and familial autoimmunity. Kaplan-Meier analysis revealed a statistically significant increased risk of losing two lines of vision on the Snellen chart for visual acuity (HR = 2.51, 95% CI = 1.00-6.29, P = 0.049).Conclusion The development of PolyA in NIU can lead to a more rapid loss of two or more lines of vision. NIU patients aged 30–64 with anterior uveitis, familial autoimmunity, and positive ANAs require frequent follow-up to identify and manage it promptly.