PurposeAssess long-term outcome of combined trabeculotomy-trabeculectomy (CTT) in primary congenital glaucoma (PCG).MethodsData of PCG patients treated with CTT by a single surgeon between 1976 and 1993 were reviewed for reduction in intraocular pressure (IOP), visual acuities, surgical success rates, and need for repeat surgeries at last follow-up (FU). At the last FU, IOP<21 mm Hg without any topical antiglaucoma medication (TAM) was complete success and with 1-2 TAMs was qualified success. IOP reduction ≥30% without any TAM was modified complete success and with 1-2 TAMs was modified qualified success. IOP>21 mm Hg, IOP reduction <30%, or use of >2 TAM at last FU, or need for additional surgery was considered as failure.ResultsTwo hundred thirty eyes of 121 patients had been followed up for 21.5-38 years (mean 28.87±2.77 years). Eyes that were pthisical (3), had immeasurable IOP (2), or IOP<6 mm Hg (3) were excluded from the success analysis. At last FU, mean IOP reduction was 22.71±11.28 mm Hg and TAM score was 1.71 (0-4). Complete success was achieved in 14 (6.3%), modified complete success in 14 (6.3%), qualified success in 148 (66.7%), and modified qualified success in 140 (63.1%). Success probability was 95% till 25 years and 92, 90, 85, 79 and 68% at 26, 27, 28, 29, and 30 years, respectively. Severe visual impairment or functional blindness was found in only 13 (10.7%) patients.ConclusionCTT shows long-term success in PCG patients. All patients must be monitored for IOP control to avoid need for repeat surgeries.