Purpose: To compare the results of cultures of the proximal and distal segments of silicone tubes after dacryocystorhinostomy.

Methods: The medical records of patients undergoing a dacryocystorhinostomy and silicone intubation were reviewed. The inclusion criteria were cultures of both distal and proximal stent segments after removal, dye testing, evaluation of the tear meniscus, and notation of the presence or absence of discharge before and after removal. The exclusion criteria included the use of systemic or topical antibiotics within 1 month before tube removal.

Results: Forty-six lacrimal systems in 40 patients were included, with 6 patients having bilateral dacryocystorhinostomies. There were no cases of dacryocystitis at the time of or after tube removal. Four (9%) of the dacryocystorhinostomies failed. Forty-one (89%) of the distal tube segments had positive cultures. The distal tube cultures grew 17 (36%) gram-positive bacteria, 21 (45%) gram-negative bacteria, 7 (15%) skin flora, and 2 (4%) fungi (6 distal segments had mixed cultures). Thirteen (28%) of the proximal tube segments had positive cultures. The proximal tube cultures were 5 (38%) gram-negative bacteria, 4 (31%) gram-positive bacteria, 3 (23%) skin flora, and 1 (8%) acid-fast bacteria. Four (31%) of the proximal tubes with positive cultures grew the same organism as the distal tube segment. Nine (69%) of the proximal tubes with positive cultures grew different organisms than the distal segment. Forty-two (91%) of all the proximal tube cultures were either negative or grew different organisms than the distal segment cultures.

Conclusions: The proximal segment of a silicone tube after a dacryocystorhinostomy may be a “privileged” area. There is usually a lack of growth or the growth of different organisms than those present on the distal tube segments. This may be explained by the protective nature of the tear film. The findings may also help to explain the low incidence of dacryocystitis in spite of the growth of virulent organisms on the distal tube segment after a dacryocystorhinostomy.