Tear Potassium Contributes to Maintenance of Corneal Thickness

Green, Keith; MacKeen, Donald L.; Slagle, Tracey; Cheeks, Lisa

doi:10.1159/000267153

Cited by 18 publications

(7 citation statements)

References 11 publications

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“…In addition, HPG borate rheology was characterized under conditions relevant to ophthalmic applications. For example, human tear films contain large quantities of electrolytes, including sodium (130−140 mM), potassium (22−43 mM), calcium (0.6−0.8 mM), chloride (118−137 mM), and bicarbonate (29−50 mM). Most experiments were conducted in a solution containing 0.1 M NaCl and 0.05 M sodium borate pH buffer (pH 7.8) to simulate physiological conditions.…”

Section: Resultsmentioning

confidence: 99%

Hydroxypropyl Guar−Borate Interactions with Tear Film Mucin and Lysozyme

Kostanski

Ketelson

et al. 2005

Langmuir

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The interactions of hydroxypropyl guar (HPG) with boric acid, lysozyme, and mucin were characterized by rheology, light scattering, electrophoresis, and isothermal titration calorimetry to help understand how HPG interacts with tear film components. Borate binds to guar under pH, temperature, and ionic strength conditions representative of those found in the eye. The HPG-borate complexes behave as anionic polyelectrolytes and thus interact with cationic lysozyme, a major tear film protein, whereas HPG-borate does not appear to bind to mucin, an anionic glycoprotein. The interactions of HPG, borate, lysozyme, and mucin can be explained by two physical interactions: (1) pH-dependent binding of borate to carbohydrates and (2) the electrostatic attraction of oppositely charged macromolecules.

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Section: Resultsmentioning

confidence: 99%

Hydroxypropyl Guar−Borate Interactions with Tear Film Mucin and Lysozyme

Kostanski

Ketelson

et al. 2005

Langmuir

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“…The neutralization process resulted in lower pH but higher osmolality (183.67 ± 1.25 mOsmol L −1 ), which is in the range of the osmolality of artificial tears (from 181 to 354 mOsmol L −1 ) [ 24 , 25 ], but this also allows the inclusion of further additives to the formulation. Ocular lubricants utilized in DED usually contain electrolytes (e.g., bicarbonate, potassium, and other electrolytes), surfactants, and various types of viscosity-increasing agents [ 26 , 27 ].…”

Section: Discussionmentioning

confidence: 99%

Cationic Thiolated Poly(aspartamide) Polymer as a Potential Excipient for Artificial Tear Formulations

Budai-Szűcs

Horvát

Szilágyi

et al. 2016

Journal of Ophthalmology

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Dry eye disease is a relatively common ocular problem, which causes eye discomfort and visual disorders leading to a decrease in the quality of life. The aim of this study was to find a possible excipient for eye drop formulations, which is able to stabilize the tear film. A cationic thiolated polyaspartamide polymer, poly[(N-mercaptoethylaspartamide)-co-(N-(N′,N′-dimethylaminoethyl)aspartamide)] (ThioPASP-DME), was used as a potential vehicle. Besides satisfying the basic requirements, the chemical structure of ThioPASP-DME is similar to those of ocular mucins as it is a protein-like polymer bearing a considerable number of thiol groups. The solution of the polymer is therefore able to mimic the physiological properties of the mucins and it can interact with the mucus layer via disulphide bond formation. The resultant mucoadhesion provides a prolonged residence time and ensures protective effect for the corneal/conjunctival epithelium. ThioPASP-DME also has an antioxidant effect due to the presence of the thiol groups. The applicability of ThioPASP-DME as a potential excipient in eye drops was determined by means of ocular compatibility tests and through examinations of the interactions with the mucosal surface. The results indicate that ThioPASP-DME can serve as a potential eye drop excipient for the therapy of dry eye disease.

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“…Additionally, higher Ca 2+ ion concentrations in tear fluid of children can indicate cystic fibrosis . K + ions play a role in the maintenance of corneal thickness and that K + ion deficiency in the tear film leads to corneal swelling . Ca 2+ and Mg 2+ ion quantification in tears have the potential to determine hypo‐ or hypercalcemia .…”

mentioning

confidence: 99%

Scleral Lens Sensor for Ocular Electrolyte Analysis

et al. 2019

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The quantitative analysis of tear analytes in point‐of‐care settings can enable early diagnosis of ocular diseases. Here, a fluorescent scleral lens sensor is developed to quantitatively measure physiological levels of pH, Na+, K+, Ca2+, Mg2+, and Zn2+ ions. Benzenedicarboxylic acid, a pH probe, displays a sensitivity of 0.12 pH units within pH 7.0–8.0. Crown ether derivatives exhibit selectivity to Na+ and K+ ions within detection ranges of 0–100 and 0–50 mmol L−1, and selectivities of 15.6 and 8.1 mmol L−1, respectively. A 1,2 bis(o‐aminophenoxy)ethane‐N,N,‐N',N'‐tetraacetic‐acid‐based probe allows Ca2+ ion sensing with 0.02–0.05 mmol L−1 sensitivity within 0.50–1.25 mmol L−1 detection range. 5‐Oxazolecarboxylic acid senses Mg2+ ions, exhibiting a sensitivity of 0.10–0.44 mmol L−1 within the range of 0.5–0.8 mmol L−1. The N‐(2‐methoxyphenyl)iminodiacetate Zn2+ ion sensor has a sensitivity of 1 µmol L−1 within the range of 10–20 µmol L−1. The fluorescent sensors are subsequently multiplexed in the concavities of an engraved scleral lens. A handheld ophthalmic readout device comprising light‐emitting diodes (LEDs) and bandpass filters is fabricated to excite as well as read the scleral sensor. A smartphone camera application and an user interface are developed to deliver quantitative measurements with data deconvolution. The ophthalmic system enables the assessment of dry eye severity stages and the differentiation of its subtypes.

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Tear Potassium Contributes to Maintenance of Corneal Thickness

Cited by 18 publications

References 11 publications

Hydroxypropyl Guar−Borate Interactions with Tear Film Mucin and Lysozyme

Hydroxypropyl Guar−Borate Interactions with Tear Film Mucin and Lysozyme

Cationic Thiolated Poly(aspartamide) Polymer as a Potential Excipient for Artificial Tear Formulations

Scleral Lens Sensor for Ocular Electrolyte Analysis

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