Postoperative endophthalmitis: incidence, predisposing surgery, clinical course and outcome.

OBJECTIVE: To describe the predisposing surgery, clinical course and final visual outcome for patients with culture-proven and culture-negative postoperative endophthalmitis.

DESIGN: Case series.

SETTING: University-affiliated teaching hospital in Toronto.

PATIENTS: A total of 164 patients with clinically suspected postoperative endophthalmitis admitted between January 1989 and March 1996.

OUTCOME MEASURES: Type of surgery, clinical presentation, culture results, infecting organism, treatment and final visual outcome.

RESULTS: An infectious agent was identified in 99 cases (60%). The organism most commonly isolated was coagulase-negative Staphylococcus (59 cases [60%]). In the culture-proven group cataract extraction was the most common predisposing surgical procedure, accounting for 85 cases (extracapsular cataract extraction [ECCE] in 60 cases and phacoemulsification in 25). The incidence rates of culture-proven endophthalmitis over the study period at our institution were 0.22% for ECCE and 0.30% for phacoemulsification. Of the 99 patients with culture-proven endophthalmitis 94 received intravitreal injections of antibiotics and 52 underwent vitrectomy. Of the 83 patients in this group for whom the final outcome was known, 29 (35%) had a visual acuity of 20/50 or better, and 15 (18%) had a vision of no light perception, with four eyes undergoing enucleation. Infection with organisms of low virulence (coagulase-negative Staphylococcus or Propionibacterium acnes) was associated with higher rates of 20/50 or better visual acuity compared with more virulent organisms (Staphylococcus aureus, streptococcal species and gram-negative bacilli) (46% vs. 10%) (p < 0.05). The culture-negative group had a significantly lower frequency of hypopyon on presentation (55% vs. 85%) and final outcome of no light perception (2% vs. 18%) (p < 0.01) than the culture-proven group.

CONCLUSIONS: Endophthalmitis was most common after cataract surgery. The rates of endophthalmitis after ECCE and phacoemulsification were similar. Postoperative endophthalmitis caused by organisms other than coagulase-negative Staphylococcus or P. acnes carries a poor visual outcome.