BCLA CLEAR Presbyopia: Management with contact lenses and spectacles.

This paper seeks to outline the history, market situation, clinical management and product performance related to the correction of presbyopia with both contact lenses and spectacles. The history of the development of various optical forms of presbyopic correction are reviewed, and an overview is presented of the current market status of contact lenses and spectacles. Clinical considerations in the fitting and aftercare of presbyopic contact lens and spectacle lens wearers are presented, with general recommendations for best practice.

Short-Term Fit Assessment of a Novel Daily Disposable, Toric, Silicone Hydrogel Contact Lens.

Purpose: The development of new contact lens materials and designs are necessary to minimise patient dropout. A lens material with water surface technology was recently developed to incorporate toric design. The on-eye stability of a toric contact lens is critical to a successful toric lens fitting.

In vitro assessment of the biocompatibility of chemically treated silicone materials with human lens epithelial cells.

Cytotoxicity testing is a regulatory requirement for safety testing of new ocular implants. In vitro toxicity tests determine whether toxic chemicals are present on a material surface or leach out of the material matrix. A method of evaluating the cytotoxicity of ocular implants was developed using fluorescent viability dyes.

Clinical Comparison of a Silicone Hydrogel and a Conventional Hydrogel Daily Disposable Contact Lens.

Purpose: To compare the subjective performances of verofilcon A daily disposable silicone hydrogel contact lenses (CLs) and etafilcon A hydrogel CLs.

Methods: Successful wearers of spherical soft CLs for distance correction were prospectively randomized to wear verofilcon A or etafilcon A lenses for 1 week and crossed over to the alternative lenses. The primary study objective was a comparison of distance visual acuity (VA).

Determining the Toxicity of UV Radiation and Chemicals on Primary and Immortalized Human Corneal Epithelial Cells.

This article describes the methods of measuring the toxicity of ultraviolet (UV) radiation and ocular toxins on primary (pHCEC) and immortalized (iHCEC) human corneal epithelial cell cultures. Cells were exposed to UV radiation and toxic doses of benzalkonium chloride (BAK), hydrogen peroxide (H2O2), and sodium dodecyl sulfate (SDS). Metabolic activity was measured using a metabolic assay.

Activity of Deposited Lysozyme on Contemporary Soft Contact Lenses Exposed to Differing Lens Care Systems.

Purpose: The amount of protein deposition on soft contact lenses and to what extent the proteins are denatured may have an impact on comfortable wearing times of contact lenses. The purpose of this study was to evaluate the effects of two lens care systems on total protein and the quantity and activity of lysozyme deposited on worn senofilcon A, silicone hydrogel contact lenses.

Participants And Methods: Thirty symptomatic soft contact lens wearers were enrolled into a 4-week prospective, randomized, bilateral eye, daily-wear, crossover, double-masked study.

Optimization of goblet cell density quantification methods.

The purpose of this study was to develop a standardized, accurate and efficient method for estimating conjunctival goblet cell density (GCD) via optimizing sample storage conditions and quantification methods. Conjunctival impression cytology (CIC) membranes were collected from both eyes of 32 participants and were randomized to two storage durations (2-3 weeks, 6-7 weeks) and two storage container types (microcentrifuge tube, flat histology cassette). The CIC membranes were stained and subdivided into 25 areas (5 mm × 5 mm) for imaging and the GCs were counted under 200X magnification using three different methods: (1) full CIC membrane GC count of the 25 images with cell-counting software ("full"; reference method), (2) partial membrane GC count of 9 images with cell-counting software ("partial"), and (3) manual counting of the 25 images ("manual").

In vitro Evaluation of the Location of Cholesteryl Ester Deposits on Monthly Replacement Silicone Hydrogel Contact Lens Materials.

Purpose: The deposition profile of cholesteryl ester on the surface and throughout the matrix of silicone hydrogel contact lens (CL) materials was determined under conditions that mimic a daily wear regimen.

Methods: In this in vitro study, four SiHy CL materials (senofilcon C, lotrafilcon B, comfilcon A and samfilcon A) were incubated in an artificial tear solution (ATS) for up to 30 days. CL incubation was alternated between the ATS (16 hours) and a multipurpose care regimen (8 hours).

Nanoscale Characteristics of Ocular Lipid Thin Films Using Kelvin Probe Force Microscopy.

Purpose: To describe the use of Kelvin probe force microscopy (KPFM) to investigate the electrical surface potential of human meibum and to demonstrate successful use of this instrument on both human meibum and a meibum model system (six-lipid stock [6LS]) to elucidate nanoscale surface chemistry and self-assembly characteristics.

Materials And Methods: 6LS and meibum were analyzed in this study. Mica-supported thin films were created using the Langmuir-Blodgett trough.

The Effect of Antimicrobial Peptides on the Viability of Human Corneal Epithelial Cells.

Antimicrobial peptides are polypeptides composed of less than 100 amino acids and are a class of antibiotics with strong activity against some infectious bacteria. This study examined the safety of four chosen antimicrobial peptides using primary human corneal epithelial cells (HCEC) and explored their potential therapeutic use. The efficacy of the peptides was also studied by evaluating the minimum inhibitory concentrations (MIC) against Gram-negative and Gram-positive bacteria.

Lipid deposition on contact lenses in symptomatic and asymptomatic contact lens wearers.

Purpose: Lipid deposition on contact lenses (CL) has traditionally been believed to reduce comfort during CL wear. The purpose of this study was to quantify lipid deposition on CL in a group of symptomatic and asymptomatic adapted CL wearers.

Methods: This was a single-masked, randomized clinical trial.

Effect of Artificial Tear Formulations on the Metabolic Activity of Human Corneal Epithelial Cells after Exposure to Desiccation.

Artificial lipid-containing tear formulations are developed to reduce tear evaporation by the restoration of a deficient tear lipid layer. Artificial tear formulations that prevent cell desiccation will result in ocular surface protection and the maintenance of cell metabolic activity. During dehydration, cells undergo the process of loss of metabolic activity and subsequently cell death.

Kinetic Deposition of Polar and Non-polar Lipids on Silicone Hydrogel Contact Lenses.

: This study investigated kinetic lipid uptake to four silicone hydrogel (SiHy) lenses over a period of four weeks, using an radiolabel method. : Four contemporary monthly replacement SiHy lenses (lotrafilcon B, senofilcon C, comfilcon A, samfilcon A) were incubated in three different solutions: 1) An artificial tear solution (ATS) containing C-labeled phosphatidylcholine (PC), 2) an ATS containing C-cholesteryl oleate (CO) and 3) an ATS containing four C-radiolabeled lipids (PC, phosphatidylethanolamine, CO, and cholesterol (total lipid)). After 16 hours, lipids were extracted twice from the lenses with chloroform:methanol and the radioactive counts determined the lipid quantities to simulate 1 day of wear.

Adhesion of , , , to contact lenses under the influence of an artificial tear solution.

Corneal infection is a devastating sight-threatening complication that is associated with contact lens (CL) wear, commonly caused by . Lately, , , and have been associated with corneal infection. This study investigated the adhesion of these emerging pathogens to CLs, under the influence of an artificial tear solution (ATS) containing a variety of components commonly found in human tears.

Cytomorphological assessment of the lid margin in relation to symptoms, contact lens wear and lid wiper epitheliopathy.

Purpose: Lid wiper epitheliopathy (LWE) is insufficiently understood from a cytological perspective. This study explored the relationship between lid margin cytomorphology, LWE, contact lens wear, and lens-related symptoms.

Methods: Habitual, symptomatic (n = 20) and asymptomatic (n = 20) soft, rigid gas permeable (n = 18) and non-contact lens wearers (n = 19) were enrolled.

Localization of full-length recombinant human proteoglycan-4 in commercial contact lenses using confocal microscopy.

The aim of this study was to determine the sorption location of full-length recombinant human proteoglycan 4 (rhPRG4) tagged with fluorescein isothiocyanate (FITC) to four silicone hydrogel contact lenses [balafilcon A (PureVision, Bausch + Lomb), senofilcon A (Acuvue Oasys, Johnson & Johnson), comfilcon A (Biofinity, CooperVision), lotrafilcon B (Air Optix, Alcon)] and one conventional hydrogel lens [etafilcon A (Acuvue 2, Johnson & Johnson)], using confocal laser scanning microscopy (CLSM). Lenses ( = 3 each) were incubated under two conditions: (1) FITC-rhPRG4 solution at 300 μg/mL and (2) phosphate-buffered saline, for 1 h at 37 °C in darkness with gentle shaking. The central 4 mm of each lens was removed and viewed with the Zeiss 510 CLSM using an argon laser at 488 nm (FITC excitation 495 nm, emission 521 nm).

Uptake and Release of Polyvinyl Alcohol from Hydrogel Daily Disposable Contact Lenses.

Significance: Polyvinyl alcohol is a wetting agent that could reduce the symptoms of dry eye and contact lens discomfort. Currently, only one lens type, nelfilcon A (DAILIES AquaComfort Plus), releases polyvinyl alcohol. The concept of releasing this agent from contact lenses could be applied to other lens materials.

Novel in vitro method to determine pre-lens tear break-up time of hydrogel and silicone hydrogel contact lenses.

Purpose: To develop an in vitro model to determine pre-lens non-invasive break-up time (NIBUT) and to subsequently use this method to compare the NIBUT over contemporary daily disposable (DD) contact lenses (CL).

Methods: Three silicone hydrogel (SH) and two conventional hydrogel (CH) DD CLs were incubated in an artificial tear solution (ATS). A model blink cell (MBC) was utilised to mimic intermittent air exposure.

Analysis of polyvinyl alcohol release from commercially available daily disposable contact lenses using an in vitro eye model.

The purpose of this work was to determine the release of polyvinyl alcohol (PVA) from etafilcon A, omafilcon A, and nelfilcon A daily disposable hydrogel contact lenses using a novel in vitro model. PVA is an ocular lubricant that can be found in multiple formulations of artificial tears. Nelfilcon A innately contains PVA, so only the release of PVA from this lens was evaluated.

Efficacy of Contact Lens Care Solutions in Removing Cholesterol Deposits From Silicone Hydrogel Contact Lenses.

Purpose: To determine the efficacy of multipurpose solutions (MPSs) on the removal of cholesterol deposits from silicone hydrogel (SH) contact lens materials using an in vitro model.

Materials And Methods: Five SH lens materials: senofilcon A, comfilcon A, balafilcon A, lotrafilcon A, and lotrafilcon B were removed from the blister pack (n=4 for each lens type), incubated for 7 days at 37°C in an artificial tear solution containing C radiolabeled cholesterol. Thereafter, lenses were stored in a preserved saline solution control (Sensitive Eyes Saline Plus) or cleaned with 1 of the 5 MPSs incorporating different preservatives (POLYQUAD/ALDOX, polyquaternium-1/alexidine, polyquaternium-1/PHMB, and 2 based on PHMB alone) using a rub and rinse technique, according to the manufacturer's recommendations, and stored in the MPS for a minimum of 6 hr.

Determination of the release of PEG and HPMC from nelfilcon A daily disposable contact lenses using a novel in vitro eye model.

The traditional method to measure release of components from CLs is a vial containing a static volume of PBS (phosphate buffered saline). However, this model does not simulate physiologically relevant tear volume and natural tear flow, air exposure, and mechanical rubbing. These factors can significantly impact release kinetics.

Surface versus bulk activity of lysozyme deposited on hydrogel contact lens materials in vitro.

Purpose: To determine and compare the levels of surface versus bulk active lysozyme deposited on several commercially available hydrogel contact lens materials.

Methods: Hydrogel contact lens materials [polymacon, omafilcon A, nelfilcon A, nesofilcon A, ocufilcon and etafilcon A with polyvinylpyrrolidone (PVP)] were incubated in an artificial tear solution for 16 h. Total activity was determined using a standard turbidity assay.

The Effect of Denatured Lysozyme on Human Corneal Epithelial Cells.

Purpose: During contact lens wear, the amount of lysozyme deposited on contact lenses varies depending on the lens material. The binding of lysozyme to some contact lens materials may result in a conformational change that denatures the protein to an inactive form. This investigation evaluated the effect that denatured lysozyme has on human corneal epithelial cells (HCECs) by measuring cell viability and the release of inflammatory cytokines.

Differential Deposition of Fluorescently Tagged Cholesterol on Commercial Contact Lenses Using a Novel In Vitro Eye Model.

Purpose: We evaluate the differences in lipid uptake and penetration in daily disposable (DD) contact lenses (CL) using a conventional "in-vial" method compared to a novel in vitro eye model.

Methods: The penetration of fluorescently labelled 22-(N-(7-Nitrobenz-2-Oxa-1,3-Diazol-4-yl)Amino)-23,24-Bisnor-5-Cholen-3beta-Ol (NBD)-cholesterol on three silicone hydrogel (SH) and four conventional hydrogel (CH) DD CLs were investigated. CLs were incubated for 4 and 12 hours in a vial, containing 3.