Mark Willcox

The TFOS International Workshop on Contact Lens Discomfort: report of the contact lens interactions with the tear film subcommittee.

Department of Ophthalmology, New Zealand National Eye Centre, University of Auckland, Auckland, New Zealand School of Optometry and Vision Science, University of New South Wales, Sydney, New South Wales, Australia Schepens Eye Research Institute and Massachusetts Eye and Ear, Harvard Medical School, Boston, Massachusetts Optometric Technology Group Research & Consultancy, London, United Kingdom Centre for Contact Lens Research, School of Optometry and Vision Sciences, University of Waterloo, Waterloo, Ontario, Canada Glasgow Caledonian University, Glasgow, United Kingdom University of Miami, Miller School of Medicine Department of Ophthalmology, Bascom Palmer Eye Institute, Miami, Florida Department of Ophthalmology, Kyoto Prefectural University of Medicine, Kyoto, Japan

1α, 25-dihydroxyvitamin D3 inhibits pro-inflammatory cytokine and chemokine expression in human corneal epithelial cells colonized with Pseudomonas aeruginosa

The cytokines IL‐1β, IL‐6 and the chemokine IL‐8 are key mediators of host inflammation. 1α,25‐Dihydroxyvitamin D3 (VD3) has been shown to regulate host immune responses in vivo and in vitro. The purpose of this study was to investigate whether the addition of VD3 to human corneal epithelial cells colonized with Pseudomonas aeruginosa altered the expression of IL‐1β, IL‐6 and IL‐8. An immortalized human corneal epithelial (HCE) cell line was used in this study. After growth to confluency, HCE cells were challenged with P. aeruginosa strain 6294 in the presence or absence of 10−6 mol/L VD3 for 4 h, 8 h and 12 h. Gene expression of IL‐1β, IL‐6 and IL‐8 was detected by reverse transcription‐PCR (RT‐PCR) from total RNA extracted from HCE cells. Protein concentrations of IL‐1β, IL‐6 and IL‐8 in culture supernatants were measured by ELISA. Addition of VD3 to HCE cells colonized with P. aeruginosa significantly inhibited the expression of IL‐1β and IL‐8 mRNA and protein (P < 0.05). Although the expression of IL‐6 mRNA was stimulated at 12 h post‐challenge (P < 0.05), the expression of IL‐6 protein was inhibited at all time points after the addition of VD3. In conclusion, this study demonstrated that VD3 inhibited the P. aeruginosa‐induced expression of IL‐1β, IL‐6 and IL‐8 in HCE cells, suggesting that this vitamin may have the potential to become a novel anti‐inflammatory agent in ocular disease.

The TFOS International Workshop on Contact Lens Discomfort: executive summary.

Contact lens discomfort (CLD) is a frequently experienced problem, with most estimates suggesting that up to half of contact lens wearers experience this problem with some frequency or magnitude. This condition impacts millions of contact lens wearers worldwide. Yet, there is a paucity of consensus and standardization in the scientific and clinical communities on the characterization of the condition, including the definition, classification, epidemiology, pathophysiology, diagnosis, management, influence of contact lens materials, designs and care, and the proper design of clinical trials. The Tear Film & Ocular Surface Society (TFOS), which is a nonprofit organization, has conducted two prior international, consensus building workshops, including the Dry Eye WorkShop (DEWS; available in the public domain at http://www.tearfilm.org/tearfilm-reports-dews-report.php) and the Meibomian Gland Dysfunction Workshop (MGD; available in the public domain at http://www.tearfilm.org/tearfilm-reports-mgdreport.php). To that end, TFOS initiated the process of conducting a similar workshop in January 2012—a process that took approximately 18 months to complete and included 79 experts in the field. These experts participated in one or more topical subcommittees, and were assigned with taking an evidence-based approach at evaluating CLD. Eight topical subcommittees were formed, with each generating a related report, all of which were circulated for presentation, review, and input of the entire workshop membership. The entire workshop originally is being published in this issue of IOVS, in English, with subsequent translations into numerous other languages. All of this information is intended to be available and accessible online, free of charge. This article is intended to serve as an Executive Summary of the eight subcommittee reports, and all information contained here was abstracted from the full reports.

The effect of eye closure on protein and complement deposition on Group IV hydrogel contact lenses: relationship to tear flow dynamics.

PURPOSE This study was designed to determine the effect of overnight eye closure on the rate and composition of protein deposition on high water content ionic matrix soft contact lenses (Group IV SCLs) and to extrapolate from this data information on the probable change in the rate of reflex-type tear secretion associated with eye closure. METHODS Group IV SCLs were temporally sampled after equivalent periods of wear under closed eye (C) or open eye (O) conditions. Lenses were rinsed in saline and the majority of the tightly bound protein extracted at 90 degrees C in 40% urea, containing 1% SDS, 1 mM DTT, 100 mM Tris-HCl (pH 8.00). Residual protein was determined by Coomassie staining of the extracted lenses and densitometric analysis. Extracted protein was quantitated and separated by SDS-PAGE. Gels were either stained with Coomassie blue or reversibly stained with imidazole-zinc and blotted. Blots were PAS stained, or lectin and antibody probed for glycoproteins, secretory IgA (sIgA), IgG, lysozyme and complement C3. Laboratory simulated deposition studies were carried out on unworn lenses exposed to HPLC purified lysozyme. RESULTS The protein in the saline rinse, to a large degree mirrored the composition of tear fluid in which the lens had been residing (O or C). This would suggest that the saline wash consists of residual tear fluid and loosely adherent protein. In contrast, the urea extracts were highly homogeneous consisting primarily of lysozyme and to lesser extent lysozyme dimer. This supports the contention that the Group IV SCL functions in the eye much as cationic exchange resin selectively absorbing lysozyme. C extracts also proved relatively enriched in trace amounts of sIgA, IgG and complement C3 and its breakdown products. High levels of C3 and C3 breakdown products were specifically recovered only in the C worn lens extracts from a subject experiencing unilateral contact lens associated corneal infiltrates from the affected eye. In all subjects, markedly less protein (lysozyme) was recovered in urea extracts of lenses exposed to 7-8 h of closed eye as compared to open eye wear (0.20 +/- .08 versus 0.79 +/- .15 mg/lens (n = 6)). Temporal studies further revealed that deposition was linearly related to duration of wear during the initial phase of conditioning film formation giving rise to rate constants for lysozyme deposition of 2.2 +/- 0.29 (n = 5) and 0.20 +/- 0.06 microgram/min (n = 4) under open and closed eye conditions respectively. With further wear, deposition eventually reached a steady state. Under laboratory conditions, lysozyme was much rapidly and quantitatively removed from solution in a manner following a hyperbolic plot. This suggests that during the initial phase of deposition the rate of deposition is limited by the capacity of the tear fluid to deliver lysozyme to the lens surface under these two extremes of conditions. CONCLUSIONS Eye closure profoundly affects the rate of lysozyme deposition on Group IV hydrogels and the composition of minor biofilm constituents in a manner that could affect biocompatibility. Findings support the contention that eye closure results in a > 90% reduction in the rate of reflex-type tear secretion.

Potential sources of bacteria that are isolated from contact lenses during wear.

Purpose The aim of this paper was to determine the possible contamination sources of contact lenses during wear. Methods Potential sources of the microbiota that colonized hydrogel contact lenses during wear were examined. The microorganisms that colonize contact lenses were grown, identified, and compared to those microorganisms that colonized the lower lid margins, upper bulbar conjunctiva, hands, and contact lens cases of contact lens wearers. In addition, the incidence of contamination of the domestic water supply in the Sydney area was obtained, and this was compared to the incidence of colonization of contact lenses by microorganisms in general and gram-negative bacteria in particular. Results There was a wide diversity of bacteria that were isolated from each site sampled. Coagulase-negative staphylococci and Propionibacterium spp. were the most common isolates from all ocular sites examined, and constituted the normal ocular microbiota. Other bacteria, including members of the families Enterobacteriaceae and Pseudomonadaceae, were isolated infrequently from all sites, but most frequently from contact lens cases. Statistical analysis revealed that there was a correlation between the isolation of bacteria from the contact lens and the lower lid margin (p < 0.001). Analysis of this correlation revealed that this was true for the normal microbiota. A correlation was also noted between the colonization of contact lenses by gram-negative bacteria and contamination of the domestic water supply. Discussion This study has demonstrated that the likely route for the normal ocular microbiota colonizing contact lenses is via the lid margins, whereas colonization by gram-negative bacteria, including potential agents of microbial keratitis, is likely to be from the domestic water supply.

A Comparison of Patient Matched Meibum and Tear Lipidomes

PURPOSE To quantify the molecular lipid composition of patient-matched tear and meibum samples and compare tear and meibum lipid molecular profiles. METHODS Lipids were extracted from tears and meibum by bi-phasic methods using 10:3 tert-butyl methyl ether:methanol, washed with aqueous ammonium acetate, and analyzed by chip-based nanoelectrospray ionization tandem mass spectrometry. Targeted precursor ion and neutral loss scans identified individual molecular lipids and quantification was obtained by comparison to internal standards in each lipid class. RESULTS Two hundred and thirty-six lipid species were identified and quantified from nine lipid classes comprised of cholesterol esters, wax esters, (O-acyl)-ω-hydroxy fatty acids, triacylglycerols, phosphatidylcholine, lysophosphatidylcholine, phosphatidylethanolamine, sphingomyelin, and phosphatidylserine. With the exception of phospholipids, lipid molecular profiles were strikingly similar between tears and meibum. CONCLUSIONS Comparisons between tears and meibum indicate that meibum is likely to supply the majority of lipids in the tear film lipid layer. However, the observed higher mole ratio of phospholipid in tears shows that analysis of meibum alone does not provide a complete understanding of the tear film lipid composition.

The TFOS International Workshop on Contact Lens Discomfort: Report of the Subcommittee on Neurobiology

This report characterizes the neurobiology of the ocular surface and highlights relevant mechanisms that may underpin contact lens-related discomfort. While there is limited evidence for the mechanisms involved in contact lens-related discomfort, neurobiological mechanisms in dry eye disease, the inflammatory pathway, the effect of hyperosmolarity on ocular surface nociceptors, and subsequent sensory processing of ocular pain and discomfort have been at least partly elucidated and are presented herein to provide insight in this new arena. The stimulus to the ocular surface from a contact lens is likely to be complex and multifactorial, including components of osmolarity, solution effects, desiccation, thermal effects, inflammation, friction, and mechanical stimulation. Sensory input will arise from stimulation of the lid margin, palpebral and bulbar conjunctiva, and the cornea.

Effects of eye rubbing on the levels of protease, protease activity and cytokines in tears: relevance in keratoconus.

Proteases, protease activity and inflammatory molecules in tears have been found to be relevant in the pathogenesis of keratoconus. We sought to determine the influence of eye rubbing on protease expression, protease activity and concentration of inflammatory molecules in tears.

The TFOS International Workshop on Contact Lens Discomfort: Report of the contact lens interactions with the ocular surface and adnexa subcommittee

Efron, N., Jones, L., Bron, A. J., Knop, E., Arita, R., Barabino, S., … Markoulli, M. (2013). The TFOS International Workshop on Contact Lens Discomfort: Report of the Contact Lens Interactions With the Ocular Surface and Adnexa Subcommittee. Investigative Opthalmology & Visual Science, 54(11), TFOS98. https://doi.org/10.1167/iovs.13-13187

Broad spectrum antimicrobial activity of melimine covalently bound to contact lenses.

PURPOSE To develop a stable antimicrobial contact lens, which is effective against the International Organization for Standardization (ISO) panel microorganisms, Acanthamoeba castellanii and drug resistant strains of Pseudomonas aeruginosa and Staphylococcus aureus. METHODS Melimine was covalently incorporated into etafilcon A lenses. The amount of peptide present on the lens surface was quantified using amino acid analysis. After coating, the heat stability (121°C), lens surface hydrophobicity (by captive bubble), and in vitro cytotoxicity to mouse L929 cells of the lenses were investigated. Antimicrobial activity against the micro-organisms was evaluated by viable plate count and fluorescence microscopy, measuring the proportion of cell death compared with control lenses with no melimine. RESULTS The most effective concentration was determined to be 152 ± 44 μg lens(-1) melimine on the lens surface. After coating, lenses were relatively hydrophilic and were nontoxic to mammalian cells. The activity remained high after autoclaving (e.g., 3.1, 3.9, 1.2, and 1.0 log inhibition against P. aeruginosa, S. aureus, A. castellanii, and Fusarium solani, respectively). Fluorescence microscopy confirmed significantly reduced (P < 0.001) adhesion of viable bacteria to melimine contact lenses. Viable count confirmed that lenses were active against all the bacteria and fungi from the ISO panel, Acanthamoeba and gave at least 2 log inhibition against all the multidrug resistant S. aureus and P. aeruginosa strains. CONCLUSIONS Melimine may offer excellent potential for development as a broad spectrum antimicrobial coating for contact lenses, showing activity against all the bacterial and fungal ISO panel microorganisms, Acanthamoeba, and antibiotic resistant strains of P. aeruginosa and S. aureus.