Introduction While examining a group of rheumatoid arthritis patients receiving intramuscular injections of triamcinolone acetonide, a new steroid for systemic administration, we found a high incidence of posterior subcapsular cataract (PSC) formation. There are conflicting reports in the literature regarding the incidence of PSC formation in patients receiving long term steroid therapy for various diseases.1-10 This varies from 0% to 42% (Table 1). In the control studies reported in the literature8-9 on patients with rheumatoid arthritis who were not treated with corticosteroids the incidence of PSC formation varied from 0% to 3% (Table 2). Presentation of Patients A. A complete ophthalmological examination was performed on each of 58 patients who had previously received intramuscular injections of triamcinolone acetonide. An incidence of 60% PSC formation was found in this group (Table 3). The cataracts were typical of those described by Black et al.6-7 Occurrence of PSC in Triamcinolone