Hypochlorous Acid 0.01% vs Povidone-Iodine 5% for Ocular Antisepsis

An alternative ocular antiseptic is needed for patients who do not tolerate povidone-iodine (PI). The purpose of this study is to compare the antimicrobial effect of hypochlorous acid (HA) 0.01% with PI 5% applied topically to the ocular surface.

Swabs of the inferior conjunctiva and posterior lower eyelid margin of 40 patients were taken from both eyes and plated onto blood agar plates. One eye was treated with HA and the other with PI, and swabs were taken after 1-minute exposure. The eye treated with PI was rinsed with sterile saline and another swab was taken. Colony-forming units (CFUs) were recorded after 2 days. Patients rated the level of irritation after treatment in each eye.

HA and PI both gave significant reduction in CFUs from baseline (P < .001 for HA and P = .002 for PI). The mean reduction in logCFU ± 95% CI was 0.850 ± 0.387 or greater for HA and 0.749 ± 0.385 or greater for PI; this was equivalent to a mean reduction of 7.1-fold or greater or 86% or greater (95% CI, 66%-94%) for HA and 5.6-fold or greater or 82% or greater (95% CI, 57%-93%) for PI. CFUs increased in 17 eyes after saline rinse. PI caused substantial irritation in 31 of the 40 participants, whereas no individuals had any irritation from topical HA.

Both HA and PI were effective in reducing ocular bacterial load. Unlike PI, HA was not irritating to the eye. Saline rinse after topical PI may increase bacterial counts in some individuals.