Study finds trends in postop endophthalmitis

Postoperative endophthalmitis in an Asian population develops more often in left eyes, among men, and following phacoemulsification, according to an epidemiologic study of cases over 7 years conducted in Singapore.

Chicago-Postoperative endophthalmitis in an Asian population develops more often in left eyes, among men, and following phacoemulsification. Good visual outcomes were associated with negative vitreous cultures, said Colin S. Tan, MD, at the annual meeting of the American Society of Cataract and Refractive Surgery.

"Endophthalmitis is a potentially devastating condition that can result in severe visual loss," said Dr. Tan, a consultant ophthalmologist at the National Healthcare Group Eye Institute at Tan Tock Seng Hospital, Singapore. "The incidences of postoperative endophthalmitis vary and range from 0.04% to 0.12% in the literature."

Endogenous and postoperative

Dr. Tan and colleagues reviewed the epidemiology of endophthalmitis and compared the clinical features and outcomes of the various types of the disease. Cases from 1999 to 2006 were included. The investigators recorded the patient demographics, type of infection, risk factors, the causative organisms, and treatments, he explained.

"Over the period of the study, 51 cases of endophthalmitis developed, 46 of which were acute and five chronic. Of the acute cases, 16 cases were endogenous and 30 exogenous, the most common of which were postoperative (19 cases); 17 cases developed after phacoemulsification and two cases after extracapsular cataract extraction. When we compared the most common groups, postoperative and endogenous endophthalmitis, we found a higher rate of endophthalmitis in patients who were non-Chinese among those with endogenous disease. The percentage of men was much higher in the group in whom the disease developed postoperatively," Dr. Tan reported.

Among the patients who developed endophthalmitis postoperatively, the left eye was involved twice as often (68.4%) compared with the right eye, he said.

Higher culture-positive results

The endogenous group had a higher percentage of culture-positive results, Dr. Tan said. The presentation of endophthalmitis was later in the endogenous group compared with the postoperative group, a mean of 9.4 versus 1.6 days, respectively.

The incidence of postoperative endophthalmitis was 0.06% over the 8-year period.

"Multivariate analyses showed that men develop endophthalmitis more than women, with an odds ratio of 2:5," Dr. Tan said. "Left eyes had a rate of endophthalmitis that was twice that of right eyes. The mean age of the patients who developed endophthalmitis was slightly higher compared with patients who did not develop endophthalmitis, a difference that trended toward significance."

An evaluation of the cases based on the wound site did not reveal any pattern regarding the development of infection.

Grouping by visual outcome

Considering the visual outcomes, the patients were divided into two groups: 20/40 or better and worse than 20/40.

"We found that the patients who developed endophthalmitis postoperatively had a higher rate of good visual outcomes compared with those in the endogenous group or those who developed the infection after a trauma, which is not unexpected," Dr. Tan said.

The cases that were culture-negative had a high rate of good visual outcomes.

Risk factors found in the literature search compared with those in the study under discussion indicated differences among studies, with no definitive conclusions reached. Other risk factors that were noted in the literature but not in this study include the presence of diabetic retinopathy and posterior capsular rupture.

"In this series of patients, postoperative endophthalmitis developed more commonly in left eyes, in men, and after phacoemulsification," Dr. Tan said. "Poor final visual acuity levels were more common among patients with endogenous infection, post-trauma cases, and in patients with positive vitreous cultures."