ABSTRACT: Importance:Preoperative testing for cataract surgery epitomizes low-value care and still occurs frequently, even at one of the nation's largest safety-net health systems. Objective:To evaluate a multipronged intervention to reduce low-value preoperative care for patients undergoing cataract surgery and analyze costs from various fiscal perspectives. Design, Setting, and Participants:This study took place at 2 academic safety-net medical centers, Los Angeles County and University of Southern California (LAC-USC) (intervention, n?=?469) and Harbor-UCLA (University of California, Los Angeles) (control, n?=?585), from April 13, 2015, through April 12, 2016, with 12 additional months (April 13, 2016, through April 13, 2017) to assess sustainability (intervention, n?=?1002; control, n?=?511). To compare pre- and postintervention vs control group utilization and cost changes, logistic regression assessing time-by-group interactions was used. Interventions:Using plan-do-study-act cycles, a quality improvement nurse reviewed medical records and engaged the anesthesiology and ophthalmology chiefs with data on overuse; all 3 educated staff and trainees on reducing routine preoperative care. Main Outcomes and Measures:Percentage of patients undergoing cataract surgery with preoperative medical visits, chest x-rays, laboratory tests, and electrocardiograms. Costs were estimated from LAC-USC's financially capitated perspective, and costs were simulated from fee-for-service (FFS) health system and societal perspectives. Results:Of 1054 patients, 546 (51.8%) were female (mean [SD] age, 60.6 [11.1] years). Preoperative visits decreased from 93% to 24% in the intervention group and increased from 89% to 91% in the control group (between-group difference, -71%; 95% CI, -80% to -62%). Chest x-rays decreased from 90% to 24% in the intervention group and increased from 75% to 83% in the control group (between-group difference, -75%; 95% CI, -86% to -65%). Laboratory tests decreased from 92% to 37% in the intervention group and decreased from 98% to 97% in the control group (between-group difference, -56%; 95% CI, -64% to -48%). Electrocardiograms decreased from 95% to 29% in the intervention group and increased from 86% to 94% in the control group (between-group difference, -74%; 95% CI, -83% to -65%). During 12-month follow-up, visits increased in the intervention group to 67%, but chest x-rays (12%), laboratory tests (28%), and electrocardiograms (11%) remained low (P?