Comparative Evaluation of Bacterial Adhesion and Biofilm Formation on Contact Lenses

This study evaluates bacterial adhesion, biofilm formation, and Staphylococcus aureus (S. aureus) (ATCC 25923) colonization on medical and cosmetic contact lenses made from Hilafilcon B and Omafilcon B under simulated ocular conditions. Non-incubated lenses served as controls, and experiments were repeated three times with a variability margin of ±5%, ensuring accuracy and reliability. Results revealed that biofilm growth and bacterial adhesion were influenced by lens material, type, and incubation duration. Cosmetic lenses made from Hilafilcon B exhibited the highest biofilm growth (1.95%) after one day, highlighting their susceptibility to microbial colonization. Conversely, medical lenses made from Hilafilcon B demonstrated the lowest biofilm growth (0.63%) after seven days, indicating potential inhibitory effects on bacterial adaptation. In terms of bacterial adhesion, Omafilcon B showed lower colonization at intermediate periods, with the lowest S. aureus adhesion observed on medical Omafilcon B lenses (64.38%) after 28 days. Antibacterial contact lenses exhibited strong inhibitory effects, with zones of inhibition ranging from 15–20 mm, confirming their effectiveness in reducing microbial colonization. The interaction between lens surface hydrophilicity and bacterial adhesion was a major factor, with ionic materials demonstrating higher biofilm formation due to increased electrostatic attraction. These findings emphasize the critical role of lens material properties, such as water content and ionic charge, in modulating bacterial interactions. The study underscores the importance of selecting appropriate lens materials and implementing advanced hygiene protocols to minimize microbial risks, offering valuable insights for designing safer and more effective contact lenses.