Purpose: To describe the case of a uniocular patient with advanced primary open-angle glaucoma (POAG) and age-related cataract in the right eye and microphthalmic left eye. Methods: A 73-year-old one-eyed man presented with four years of painless, progressive dimness of vision in the right eye. The vision was 6/18 in the right eye, whereas the left eye had no light perception (NLP). In the left eye, severe ptosis and microphthalmos were detected, while the right eye had age-related cataracts, an open anterior chamber angle, intraocular pressure (IOP) of 30 mmHg, and progressive glaucomatous optic neuropathy. The IOP was dropped to 22 mmHg after a topical timolol maleate (0.5%), brimonidine tartrate (0.2%), and brinzolamide (1%). As the patient had mature cataract, advanced glaucomatous optic nerve damage, target IOP was not reached, and adherence issues with antiglaucoma medications (AGM), the decision was made to proceed with cataract extraction combined with augmented trabeculectomy with mitomycin-C (MMC). Results: There were no intraoperative complications. Over one year, the IOP was maintained in the 12–14 mmHg range without AGM. Conclusion: In advanced glaucoma patients, combined phaco-trabeculectomy operations can considerably lower IOP and drug load or compliance concerns with antiglaucoma drugs. This case represented an efficient and safe surgical technique for uniocular advanced POAG, particularly in a developing country like Bangladesh.