A 59-year-old woman was seen by an ophthalmologist for blurred vision, ocular pain, headache, and nausea. She was diagnosed with acute primary angle closure (APAC) and successfully treated with medications. Using ultrasound biomicroscopy (UBM), engorged episcleral vein was observed and small uveal effusion was diagnosed after laser peripheral iridotomy (LPI). The uveal effusion disappeared and was again diagnosed by UBM together with anterior segment inflammation with ocular pain. Iritis caused by LPI after APAC might be a cause of uveal effusion in this specific case.