To investigate antimicrobial effectiveness of povidone-iodine (Betadine) in reducing bacterial load of corneal ulcers before patients were given antibiotics.
Patients with corneal ulcers were randomized to Betadine or placebo group. Ulcers were cultured before and after a 10-minute application of 5% Betadine or preservative-free artificial tears. All patients were then treated with standard antibiotic medications. The number of colony-forming units before and after Betadine or placebo was compared.
Eighteen patients were randomized to Betadine and 17 to placebo group. In the Betadine group, 8 (44 %) of 18 ulcers were culture-positive, either before and/or after pretreatment, and in the control group, 9 (53%) of 17 were culture positive. There was No statistical difference in colony-forming units change after Betadine versus artificial tears application was detected (P-value = 0.16, t-test). In Betadine group, 3 (17%) of 18 of patients showed improvement, ie, had fewer colonies after drop application; and in the placebo group, 7 (41%) of 17 showed improvement, (P = 0.15, Fisher exact t test.)
A single application of 5% Betadine did not reduce the bacterial load of corneal ulcers more than just scraping/rinsing alone. This is likely the result of the lack of penetration deep into the corneal stroma and number of organisms present. Other factors may be involved.