A 62-year-old woman from Bangalore with a history of hyperopia and shallow anterior chamber presents with her right eye having been treated for acute angle-closure glaucoma 6 months ago with Nd:YAG laser peripheral iridotomy. She now reports gradual dimming of vision in the left eye over 3 weeks with occasional mild discomfort. Examination of the left eye reveals: visual acuity 6/12, IOP 24 mmHg, anterior chamber depth 2.0 mm, and gonioscopy shows a narrow angle (Shaffer grade 1) with the angle not yet occluded. What is the most appropriate management for the left eye?