Many contact lens wearers fail to use fresh contact lens solution each time they store their contacts, choosing instead to “top off” existing multipurpose solution in their lens case. Some lens wearers also fail to recap their storage cases, which causes some of the solution to evaporate, affecting its concentration.
Because non-compliance with proper lens care is a significant factor in contact lens-related eye infections — including fungal eye infections and Acanthamoeba keratitis — researchers at Abbott Medical Optics recently investigated the impact of partial evaporation of popular multipurpose contact lens solutions on their disinfecting effectiveness.
Solutions were partially evaporated under a stream of air to two to four times their normal concentration, and then compared with non-evaporated solutions in effectiveness at killing fungal (Fusarium solani and Candida albicans) and Acanthamoeba microorganisms associated with contact lens-related eye infections.
The study data revealed that, after partial evaporation:
- ReNu with MoistureLoc (Bausch + Lomb) lost 75 to 99 percent of its ability to kill Fusarium fungi, 90 to 100 percent of its effectiveness against Candida fungi, and 29 to 33 percent of its effectiveness against Acanthamoeba microorganisms.
- Opti-Free Replenish (Alcon) lost 72 to 90 percent of its disinfecting efficacy against Fusarium and Candida fungi, and 10 to 61 percent of its effectiveness against Acanthamoeba.
- ReNu MultiPlus (Bausch + Lomb) lost 79 percent of its effectiveness against Candida fungi (when the solution was evaporated to four times its normal concentration).
- AQuify Multi-Purpose (Ciba Vision) lost 34.5 percent of its effectiveness against Candida fungi (4x concentration).
- Biotrue (Bausch + Lomb) lost 48 percent of its effectiveness against Candida fungi (4x concentration).
- Complete RevitaLens (Abbott Medical Optics) showed no loss in disinfecting effectiveness for the microorganisms tested.
The study authors concluded that partial evaporation of many multipurpose contact lens solutions can significantly affect their disinfecting ability. Of the solutions tested, only Complete RevitaLens (Abbott Medical Optics) appeared to retain its full antimicrobial effectiveness after partial evaporation.
The study was published online by Contact Lens & Anterior Eye (Journal of the British Contact Lens Association) on March 10.