This study aimed to assess details of therapy required to achieve an intraocular pressure (IOP) of ⩽12 mmHg in patients with severe glaucoma of different etiologies. Patients with a follow-up of at least 1 year, who fulfilled inclusion criteria were selected, and data analyzed with respect to baseline IOP, number of medications, and/or surgeries required to achieve an IOP of ⩽12 mmHg and ⩾6 mmHg. Final IOP, visual field status and medications/surgery required were noted. About 127 eyes of 85 patients met all criteria. There were 48 eyes having primary angle closure glaucoma (PACG), 16 eyes with primary open angle glaucoma (POAG), 17 eyes of juvenile open angle glaucoma (JOAG), and 46 eyes of secondary glaucoma. The mean baseline IOP was 33.14 ± 11.07 mmHg and final IOP 10.25 ± 1.81 mmHg. In the age group >40 years, 29.63% of patients were controlled on medication as compared to 9.09% and 5.71% in the age group of <20 years and 20-40 years (p = 0.007). With a baseline IOP of <25 mmHg, 48.65% required a trabeculectomy, whereas for 25-30, and >30 mmHg, 62.5% and 97.29% respectively, required surgery (p < 0.001).66.67% of patients having mean deviation of -12 to -16 dB (decibels) on Humphrey field analyzer (HFA) underwent surgery to achieve target IOP in comparison to 83.52% who had mean deviation greater than -16 dB (p = 0.036). Only 21.26% of severe glaucoma eyes could be controlled on medications alone. A baseline IOP of >25 mmHg, age <40 years and mean deviation worse than -16 dB, had a higher frequency of trabeculectomies to achieve an IOP of ⩽12 mmHg.