Objective To establish risk factors for the occurrence of post traumatic endo phthalmitis, to observe the efficacy of prophylaxis, and to describe the clinica l features of post traumatic endophthalmitis. Design Partially prospective cons ecutive case control study. Participants A total of 250 consecutive patients ad mitted to a single ophthalmic hospital with open globe injuries during a 3 year period were included. Methods Patients with post traumatic endophthalmitis wer e identified prospectively and added to an endophthalmitis database. All open gl obe injuries during the same time period were identified through a retrospective search of inpatient admissions, and their charts were reviewed. Information col lected from all patient files included patient age; gender; injury setting (indo or/outdoor); wound contamination; nature of injury (site on eye, lens involvemen t, retained intraocular foreign body); mechanism of injury (penetration/perforat ion/rupture/ ruptured surgical wound); prophylactic antibiotic administration, i ncluding route and timing; timing of primary repair; lensectomy at the time of p rimary repair; and depot corticosteroid at the time of primary repair. Any assoc iation between these parameters and the subsequent development of endophthalmiti s was investigated. Any association between endophthalmitis and final visual acu ity (VA) and also enucleation was evaluated. Main outcome measure Development of endophthalmitis. Results The frequency of endophthalmitis after open globe inju ry was 6.8%. The following factors were associated with the subsequent developm ent of endophthalmitis by univariate analysis: dirty wound (14.3%vs. 4.1%, P=0 .01), retained intraocular foreign body (13.0%vs. 4.4%, P=0.02), lens capsule breach (12.8%vs. 3.2%, P=0.01), delayed primary repair (≥12 hours) (11.3%vs. 2.9%, P=0.02), and rural address (10.1%vs. 4.3%, P=0.07). Risk f actors identified after multivariate analysis were dirty injury (odds ratio [OR ] , 5.3; 95%confidence interval [CI)], 1.5-18.7), breach of lens capsule (OR, 4. 4; 95%CI, 1.2-15.6), and delay in primary repair (per hour: OR, 1.013; 95%CI, 1.002-1.024). None of the following factors was found to be associated with po st traumatic endophthalmitis: patient age, gender, injury setting, site of inju ry on eye, mechanism of injury, antibiotic administration, lensectomy at the tim e of primary repair, and depot corticosteroid at the time of primary repair. Fin al VA tended to be worse in eyes with endophthalmitis (P=0.08). Endophthalmitis did not significantly influence the frequency of enucleation/evisceration (5.9% vs. 4.3%, P =0.55). Conclusions Delay in primary repair, ruptured lens capsule, and dirty wound were each independently associated with the development of post traumatic endophthalmitis. Patients with ≥2 of these 3 risk factors had a par ticularly high frequency of infection. Objective To establish risk factors for the occurrence of post traumatic endo phthalmitis, to observe the efficacy of prophylaxis, and to describe the clinica l features of post traumatic endophthalmitis. Design Partially prospective cons ecutive case control study. Participants A total of 250 consecutive patients ad mitted to a single ophthalmic hospital with open globe injuries during a 3 year period were included. Methods Patients with post traumatic endophthalmitis wer e identified prospectively and added to an endophthalmitis database. All open gl obe injuries during the same time period were identified through a retrospective search of inpatient admissions, and their charts were reviewed. Information col lected from all patient files included patient age; gender; injury setting (indo or / outdoor); wound contamination; nature of injury (site on eye, lens involvemen t, retained intraocular foreign body); mechanism of injury (penetration / perforat ion / rupture / ruptured surgical wound) ; prophylactic antibiotic administration, i ncluding route and timing; timing of primary repair; lensectomy at the time of p rimary repair; and depot corticosteroid at the time of primary repair. . Any association between endophthalmitis and final visual acuity (VA) and also enucleation was evaluated. Main outcome measure Development of endophthalmitis. Results The frequency of endophthalmitis after open globe inju ry was 6.8%. The following factors were associated with the subsequent developm ent of endophthalmitis by univariate analysis: dirty wound (14.3% vs. 4.1%, P = 0.01), retained intraocular foreign body (13.0% vs 4.4%, P = 0.02) , P = 0.01), delayed primary repair (≥12 hours) (11.3% vs.2.9%, P = 0.02), and rural address (10.1% vs.4.3%, P = 0.07). Risk f actors identified after multivariate analysis were dirty injury (odds ratio [OR], 5.3; 9 5%Confidence interval [CI]], 1.5-18.7), breach of lens capsule (OR, 4.4; 95% CI, 1.2-15.6), and delay in primary repair -1.024). None of the following factors was found to be associated with po st traumatic endophthalmitis: patient age, gender, injury setting, site of inju ry on eye, mechanism of injury, antibiotic administration, lensectomy at the tim e of primary repair , and depot corticosteroid at the time of primary repair. Fin al VA tended to be worse in eyes with endophthalmitis (P = 0.08). Endophthalmitis did not significantly influence the frequency of enucleation / evisceration (5.9% vs. 4.3%, P = 0.55 Conclusions Delay in primary repair, ruptured lens capsule, and dirty wound were each independently associated with the development of post traumatic endophthalmitis. Patients with ≥ 2 of these 3 risk factors had a par ticularly high frequency of infection.