Initial in Vivo Tear Protein Deposition on Individual Hydrogel Contact Lenses

Leahy, Charles D.; Mandell, Robert B.; Lin, Susan

doi:10.1097/00006324-199007000-00008

Cited by 85 publications

(46 citation statements)

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“…The development of deposits on contact lenses is a well known clinical complication usually resulting in reduction of comfort, vision and increased inflammatory responses [7,18]. Lysozyme, lactoferrin, mucin and albumin have been identified to be the predominant tearfilm proteins coating the surface of hydrogel contact lenses [8,14,15,22]. The appearance of deposits is seen in about 6.8% and rises to 16.6% in patients with dry eye and to 20% in exposure keratitis and trichiasis, if the lenses were worn longer than 2 weeks [5].…”

Section: Daysmentioning

confidence: 99%

“…c+d Enlarged sectors showing the wrinkled structure and the cracks inside the coating received serum eye drops showed a band at 65 kDa, which is approximately the molecular weight of albumin. Because albumin represents 60% of the protein content of serum and is attracted by hydrogel contact lenses [14,15], it is likely that the bands contain albumin, although this hypothesis is awaiting confirmation by additional immunoblotting. The deposit containing BCL showed another light band much lower than 14 kd.…”

Section: Daysmentioning

confidence: 99%

“…The BCL of the patient with conventional therapy and the patient with serum but without deposits both showed two bands at 14 and 18 kDa. These bands could possibly be lysozyme (∼14 kDa) and PMFA (proteins migrating faster than albumin ∼15-20 kDa) [2,14].…”

Section: Daysmentioning

confidence: 99%

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Combination of serum eye drops with hydrogel bandage contact lenses in the treatment of persistent epithelial defects

Schrader¹,

Wedel²,

Moll³

et al. 2006

Graefe's Arch Clin Exp Ophthalmo

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Section: Daysmentioning

confidence: 99%

Section: Daysmentioning

confidence: 99%

See 1 more Smart Citation

Combination of serum eye drops with hydrogel bandage contact lenses in the treatment of persistent epithelial defects

Schrader¹,

Wedel²,

Moll³

et al. 2006

Graefe's Arch Clin Exp Ophthalmo

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show abstract

“…They have been used in a wide variety of applications: as biomaterials in drug release and soft contact lenses [94,103], in agriculture [104] and electrophoresis [105].…”

Section: Hydrogelsmentioning

confidence: 99%

“…To this end, material biocompatibility must be a consideration. Luckily, many examples already exist of hydrogels interfacing with the human body, including soft contacts [94,103], burn dressings [130], cell culture [131], artificial cartilage implants [132,133] and drug delivery [134]. It is the high water content of hydrogels which leads to good biocompatibility; as impurities can easily be washed out before use, the soft and pliable nature of the material reduces mechanical stress on living tissues, and provides low interfacial tension [96].…”

Section: Biocompatibilitymentioning

confidence: 99%

A Bio-inspired Excitable Cardiac Cell Membrane from Electroactive Polymers: Ion Transport Studies

Moored

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The heart is an incredibly efficient biological pump, which contracts as a whole from the coordinated effort of millions of excitable cells called cardiac myocytes. These cells are considered excitable since they possess the ability to respond to a threshold activation signal, but only if sufficient time has passed and they have recovered from their previous excitation. Excitable cells also have the capacity to propagate an activation signal to their neighboring cells, and collectively are referred to as an excitable medium. Numerous examples of excitable media exist in nature, including the heart, forest fires, the intestine, nerves, and certain kinds of chemical reactions. Engineered artificial excitable media, however, have never been developed before.The long-term goal of this project, therefore, is to develop the first such artificial excitable medium from an array of artificial excitable cells, called gel-cells. The conceptual design of the gel-cell consists of a thin electroactive ion-gating membrane (polypyrrole), sandwiched between two layers of hydrated polymer (hydrogel) loaded with different concentrations of potassium chloride (KCl aq ) electrolytes. The voltage controlled artificial membrane initially confines ions to the upper chamber of the gelcell, and releases them upon membrane opening into the lower chamber, a process similar to membrane activation in cardiac myocytes. Potassium sensing electrodes embedded throughout the gel-cell provide feedback on the location and concentration of ions within the gel-cell, becoming markers for its activation. The scope of the research presented here was to construct the biomimetic cell membrane portion of the gel-cell, and study ion transport through its assembly.First, the electrochemical response of polypyrrole (PPy) was characterized via cyclic voltammetry, and its membrane morphology and thickness were observed via scanning electron microscopy. Experimentally obtained membrane thickness values were then compared to model predictions, which were subsequently improved by updating membrane density and structure assumptions. Hydrogel pore size approximations were correlated to equilibrium water content calculations, and KCl aq concentrations were quantified using electrochemical impedance spectroscopy. Time-resolved KCl aq flux experiments were performed on PPy membranes in solution, providing real-time concentration profiles of KCl aq as it passes through the membrane. From the parameter space tested, the optimal membrane preparation and gating potentials were selected which produced the highest flux rates. Time-lapse flux experiments (providing piece-wise concentration profiles for KCl aq ) were then performed on PPy membranes in both solution and hydrogel. Ion transport through two nearly identical membranes produced under different deposition conditions (PPy a and PPy b ) were compared in solution. The slightly denser and thicker membrane (PPy b ) produced nearly an order of magnitude higher flux rates than PPy a , suggesting that an active comp...

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Surface chemical structure for soft contact lenses as a function of polymer processing

Grobe¹,

Valint²,

Ammon³

1996

J. Biomed. Mater. Res.

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The surface chemistry and topography of cast-molded Etafilcon-A and doubled-sided lathed Etafilcon-A soft contact lenses were determined to be significantly different. The variations in surface chemical and morphologic structure between the two lenses were the result of contact lens manufacturing methods. The surface of the cast-molded Etafilcon-A had a consistently less rough surface compared to the doubled sided lathed Etafilcon-A as determined by atomic force microscopy. The surface of the doubled sided lathed Etafilcon-A contained primarily silicone and wax contamination in addition to minute amounts of HEMA. The cast-molded Etafilcon-A had an elemental and chemical content which was consistent with the polymer stoichiometry. Contact angle wettability profiles revealed inherent wettability differences between the two lenses types. The cast-molded Etafilcon-A had an inherently greater water wettability, polarity, and critical surface tension. This means that these two lenses cannot be compared as similar or identical lens materials in terms of surface composition. The manufacturing method used to produce a soft contact lens directly determines the surface elemental and chemical structure as well as the morphology of the finished lens material. These results suggest possible differences in the clinical comfort, spoilage, and lubricity felt during patient wear.

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Initial in Vivo Tear Protein Deposition on Individual Hydrogel Contact Lenses

Cited by 85 publications

References 0 publications

Combination of serum eye drops with hydrogel bandage contact lenses in the treatment of persistent epithelial defects

Combination of serum eye drops with hydrogel bandage contact lenses in the treatment of persistent epithelial defects

A Bio-inspired Excitable Cardiac Cell Membrane from Electroactive Polymers: Ion Transport Studies

Surface chemical structure for soft contact lenses as a function of polymer processing

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