Purpose: To evaluate the results of conjunctival culture in patients with nasolacrimal duct obstruction (NLDO) and its changes after successful dacryocystorhinostomy surgery.
Methods: In this prospective study, 71 adult patients with NLDO and 41 age- and sex-matched controls without NLDO were evaluated. The patients were divided in 2 groups based on clinical examination; group A with purulent regurgitation and group B without purulent regurgitation. Dacryocystorhinostomy surgery was performed, and the silicon tube was inserted in patients with upper lacrimal drainage system stenosis and when the lacrimal sac or nasal mucosal flap was inadequate for suitable anastomosis. Before surgery, microbiologic specimens were taken from the conjunctiva. Postoperative conjunctival sampling was continued weekly until the culture became negative or the colony count reached to the range of the control group.
Results: There were 38 and 33 patients in groups A and B, respectively. Silicone tube was inserted for 17 patients (23.9%). The culture was positive for bacterial growth in all cases. The conjunctival culture in the control group was positive in 17 eyes (41.4%). The mean count of colonies in a sample unit was 5274 ± 6300, 1167 ± 1504, and 9.5 ± 1.5 for group A, group B, and controls, respectively. The mean time of normalization of specimens was 3.3 ± 1.3 weeks (range 1-7). Pathogenic bacterial growth, higher colony counts, the presence of silicone tube, and purulent regurgitation were significantly associated with longer normalization time (p = 0.007, p = 0.0001, p = 0.0001, and p = 0.01, respectively).
Conclusions: This study suggests that after successful dacryocystorhinostomy surgery, a waiting period of 7 weeks is enough for conjunctival bacterial cultures to become negative or reach the level of the normal eyes.