Purpose: To investigate the susceptibility of different fungal corneal isolates to commercially available contact lens disinfecting solutions.
Methods: Thirteen filamentous fungal isolates (9 Aspergillus spp, 3 Fusarium spp, 1 Curvularia sp.) recovered from corneal infections were used. The following solutions were tested: Arion Cronos, Complete Revitalens, Dua Elite, Opti-Free Express, Regard, Oxysept Comfort, and Oxysept Comfort without catalase. Suspensions of the different fungal isolates were made in the solutions (10(6) colony-forming units/mL). After 1 h (Arion Cronos only), 6, 8, and 24 h, aliquots of suspension were removed and seeded on Sabouraud agar plates.
Results: After a 6-h exposure, only 3% hydrogen peroxide-based Oxysept Comfort without catalase eradicated all the fungi tested. All the other solutions were partly ineffective at killing some of the fungal isolates, even after a 24-h exposure. The worst performance was given by Regard and Dua Elite, which, after a 6-h exposure, showed growth of 12 and 10 of the 13 fungal strains tested, respectively.
Conclusions: Most contact lens disinfecting solutions may not be sufficiently effective, if contact lens care systems become contaminated with filamentous fungi. In our experiment, only an exposure to 3% hydrogen peroxide without a neutralizer for at least 6 h was always able to kill an inoculum of different fungal strains.