Comparative efficacy of two different regimens of povidone-iodine 5% eye drops instillation in reducing conjunctival bacterial flora - a preliminary report

Abstract

Purpose: To investigate efficacy of 1 or 3 drops of povidone-iodine 5% eye instillation in reducing conjunctival bacterial flora culture positivity.

Methods: A total of 63 patients (n= 63 eyes) were included, and randomly divided to receive 1 (group PVPI; n=32) or 3 (group PVPIplus; n=31) eye-drops. Conjunctival swab was obtained five minutes before and 30 minutes after the first povidone iodine drop was instilled into the conjunctival sac of study eye. Corneal paquimetry was performed before and after procedure using OcuScan Alcon RXP (Alcon, Fortworth, Texas). Conjunctival swabs were incubated aerobically in enriched Thioglycolate liquid medium (meat broth) and in three solid culture media (Agar Chocolate, Trypticase Soy Agar with 5% sheep blood, and Agar Sabouraud).

Results: The proportion of patients that had microorganisms isolated from the conjunctival swab before and after treatment was 14/32 (43%), and 9/32 (28%) for PVPI group, and 8/31 (26%), and 3/32 (10%) for PVPIplus group. A trend towards significant difference was found for the number of positive cultures after treatment between groups (p=0.05). Staphylococcus epidermidis were the microorganisms more frequently isolated in cultures from both groups. Mean corneal thickness increased significantly in 5.7 ± 2.5 μm after treatment in the PVPI group (p=0.033; t-Test), but did not for PVPIplus (-1.2 ± 2.3 μm; P=0.300), and this change was significantly different between-groups (P=0.025). There was no significant difference in keratoconjunctivitis scores between groups.

Conclusions: This preliminary data evaluation indicates a trend towards better conjunctival bacterial flora reduction if 3 instead of 1 PVPI drops are used, without adding additional corneal toxicity. Larger samples are warranted to confirm these preliminary findings.

Keywords: 513 endophthalmitis • 433 bacterial disease • 474 conjunctiva