Idiopathic unilateral ocular vasculitis in a young adult: a case report on clinical course and steroid response.

Introduction and importance: Ocular vasculitis is an inflammatory condition affecting intraocular blood vessels, commonly associated with systemic diseases like Behçet's disease, sarcoidosis, and tuberculosis. However, idiopathic isolated ocular vasculitis is rare, particularly in young adults, and presents diagnostic difficulties. Timely recognition is vital to prevent vision loss. Case presentation: We present a 25-year-old male with unilateral, painless, progressive visual blurring and floaters in the left eye. Examination showed anterior uveitis and retinal vasculitis, including perivasculitis, venous sheathing, and subretinal exudates. Extensive systemic evaluation, including autoimmune and infectious screening, was negative. A diagnosis of idiopathic ocular vasculitis was made. The patient received a single posterior sub-Tenon injection of triamcinolone acetonide along with topical anti-inflammatory agents. Significant clinical improvement was observed, with visual acuity improving from 6/18 to 6/9 and resolution of inflammatory signs. Clinical discussion: This case highlights a rare presentation of idiopathic ocular vasculitis involving both anterior and posterior segments, without systemic association. Idiopathic cases are typically diagnosed by exclusion. While systemic corticosteroids are commonly used for vasculitis, localized steroid therapy can be safer and equally effective in isolated ocular cases. The patient's rapid response supports the role of targeted local therapy. Conclusion: Idiopathic ocular vasculitis, though rare, should be considered in patients with intraocular inflammation and no systemic findings. Exclusion of secondary causes and timely localized steroid treatment can preserve vision and prevent complications. Individualized management remains key in such rare presentations. Autoimmune and infectious causes including tuberculosis, syphilis, toxoplasmosis, and connective tissue disorders were excluded through thorough laboratory investigations. The patient was followed up for 6 months, demonstrating complete resolution and no recurrence, strengthening the role of local corticosteroid therapy in idiopathic cases.