OBJECTIVES: To examine the rate of laser iridotomy failure at the University of Cincinnati Glaucoma Service, Cincinnati, Ohio, during the last 10 years and to evaluate the importance of silicone oil pupillary block glaucoma (SOPBG) as a causal factor. METHODS: We retrospectively reviewed the operative records of all 1711 eyes that underwent laser iridotomy for the treatment of pupillary block angle-closure glaucoma between January 1, 1996, and December 31, 2005. The occurrence, etiology, timing, and rate of laser iridotomy failure were assessed with SOPBG cases analyzed separately. RESULTS: Analyses using the chi(2) test demonstrated significantly higher laser iridotomy failure rates for 13 eyes with SOPBG compared with 1698 eyes with non-SOPBG for all 3 timing outcomes (immediate, 15.4% vs 0%; short term, 92.3% vs 2.5%; and long term, 38.5% vs 0.1%; all P < .0001). To achieve long-term patency, SOPBG iridotomy failures required, on average, 2.7 laser iridotomy procedures, 4.1 periocular steroid injections, and 0.7 intracameral tissue plasminogen activator injections. CONCLUSIONS: Eyes with SOPBG require extensive resources to prevent laser iridotomy failure. In managing SOPBG, ophthalmologists should anticipate the need for additional laser treatment and use adjunctive steroids and intracameral tissue plasminogen activator to enhance long-term patency and avert invasive surgical procedures.