Role of 0.02% Polyhexamethylene Biguanide and 1% Povidone Iodine in Experimental Aspergillus Keratitis

Purpose: To determine the efficacy of 0.02% polyhexamethylene biguanide and 1% povidone iodine in experimental keratitis.

Methods: Aspergillus fumigatus keratitis was induced by corneal intrastromal injection of spores in 24 healthy rabbits that were randomly divided into four groups of six rabbits each. Drugs used were 5% natamycin (standard antifungal), 0.02% polyhexamethylene biguanide (PHMB) (test drug), 1% povidone iodine (test drug), and 0.5% hydroxypropylmethyl cellulose (HPMC) (control).

Results: The average healing times of the ulcer were 21.5 +/- 3.08 days with 5% natamycin, 27.8 +/- 2.28 days with 0.02% PHMB, 36.4 +/- 2.57 days with 1% povidone iodine, and 38.2 +/- 4.74 days with 0.5% HPMC. While no corneal perforations occurred with natamycin treatment, one perforation was noted with PHMB, three perforations were noted with povidone iodine, and five perforations were noted with controls.

Conclusion: Polyhexamethylene biguanide (0.02%) is a moderately effective drug for experimental Aspergillus keratitis, but 1% povidone iodine is not effective.