A 58-year-old woman from Delhi presents to the emergency department with acute onset severe eye pain, blurred vision, and nausea for the past 6 hours. On examination, the right eye shows mid-dilated pupil, corneal edema, conjunctival injection, and intraocular pressure (IOP) of 58 mmHg. Gonioscopy reveals appositional angle closure. The left eye is anatomically predisposed but currently asymptomatic with normal IOP. What is the most appropriate immediate next step in management?