In vitro deposition of lysozyme on etafilcon A and balafilcon A hydrogel contact lenses: Effects on adhesion and survival of Pseudomonas aeruginosa and Staphylococcus aureus

Preservation of Human Tear Protein Structure and Function by a Novel Contact Lens Multipurpose Solution Containing Protein-Stabilizing Agents

“…42,43 Although lysozyme function is typically measured by assaying Micrococcus luteus inhibition, this organism is more susceptible to lysozyme-induced lysis than P. aeruginosa and S. aureus, 44 and we therefore focused on these less susceptible yet more clinically relevant organisms. Bacterial stocks were grown by inoculating Luria-Bertani broth with either P. aeruginosa (ATCC strain 9027) or S. aureus (ATCC .…”

Lysozyme transport in p-HEMA hydrogel contact lenses

“…Group I lenses are non-ionic with low water content, group II lenses are non-ionic with high water content, group III lenses are ionic with low water content and group IV lenses are ionic with high water content. It is widely accepted that group IV Etafilcon lenses, i.e., p-HEMA with copolymer methacrylic acid (MA), deposit substantially more lysozyme than all other hydrogel lens materials [1,2,[4][5][6]10,11]. Higher water content and electrostatic interactions between lysozyme and the negatively charged MA likely drive the large uptake of lysozyme by the group IV lenses.…”

“…Numerous studies have shown that that protein transport in hydrogels is a function of several properties including water content, surface charge, protein size and charge, and surface roughness [1][2][3][4][5][6]. Protein deposits on contact lenses originate from tear proteins, and these deposits can cause a number of problems including discomfort, reduced visual acuity, dryness, and reduced lens' life.…”

“…Protein deposits on contact lenses originate from tear proteins, and these deposits can cause a number of problems including discomfort, reduced visual acuity, dryness, and reduced lens' life. Additionally, protein deposits may facilitate bacterial adhesion and subsequent infections of the eye, as well as inflammation and adverse immunological response [1][2][3][4][5]7]. Lysozyme is the most abundant protein in tear fluid [7] with normal levels ranging from 0.6 to 2.6 mg/ml [7] thereby comprising about 20-40% of tear proteins [8].…”

A Solid-Phase Assay for the Quantitation of Total Protein Eluted from Balafilcon, Lotrafilcon, and Etafilcon Contact Lenses

“…[1][2][3][4][5][6][7][8][9] The quantity of protein depositing on hydrogel lens materials varies with the lens material, water content, surface charge, [10][11][12][13][14] and characteristics of depositing proteins, such as molecular weight and overall net charge. [15][16][17] Food and Drug Administration (FDA) group IV conventional hydrogel (CH) contact lens materials, which are high water and high surface charge, deposit the most protein, with typically 500-1500 µg per lens, 8,9,11,18,19 whereas groups I-III CH lenses deposit substantially less protein, in the region of 10-30 µg per lens.…”