Can artificial tears prevent Acanthamoeba keratitis? An in vitro approach

Area of Science:

• Ophthalmology
• Microbiology
• Parasitology

Background:

• Increasing contact lens use correlates with rising Dry Eye Syndrome incidence.
• Contact lens wear and dry eye may increase Acanthamoeba infection risk.
• Artificial tears are a common dry eye treatment, necessitating evaluation of their impact on Acanthamoeba.

Purpose of the Study:

• To assess the impact of three artificial tear formulations on Acanthamoeba genotype T4 viability.
• To compare the efficacy of Optava Fusion™, Oculotect®, and Artelac® Splash against Acanthamoeba.
• To evaluate novel staining methods for Acanthamoeba viability assessment.

Main Methods:

• Acanthamoeba trophozoite viability assessed using Trypan Blue and CTC stains.
• Staining evaluated at multiple time points (2, 4, 6, 8, 24 hours).
• Viability determined by manual light microscopy counts and flow cytometry.

Main Results:

• Optava Fusion™ and Artelac® Splash showed reduced Acanthamoeba viability within 4 hours, with diminishing effect later.
• Oculotect® caused complete Acanthamoeba cell death within 2 hours.
• Flow cytometry confirmed Trypan Blue findings; Artelac® Splash reduced respiration but not membrane integrity.

Conclusions:

• CTC stain with flow cytometry is a useful, complementary method for Acanthamoeba viability assessment.
• Preservative-free Artelac® Splash and Optava Fusion™ (with Purite®) lacked significant amoebicidal activity.
• Oculotect® (with BAK) shows promise for Acanthamoeba keratitis prevention/treatment, warranting in vivo studies.