Structure–property relationship of delefilcon a lenses

Thekveli, Sibichen; Qiu, Ye; Kapoor, Yash; Liang, W. Y.; Pruitt, John

doi:10.1016/j.clae.2012.08.044

Cited by 14 publications

(14 citation statements)

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“…47 While the manufacturer did not measure the water content of the surface of the delefilcon A lens, the water content was estimated from a film of copolymer applied to a silicon wafer using neutron reflectometry. 48 …”

Section: Discussionmentioning

confidence: 99%

Evaluation of surface water characteristics of novel daily disposable contact lens materials, using refractive index shifts after wear

Schäfer¹,

Steffen²,

Reindel³

et al. 2015

OPTH

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PurposeContact lens wearers today spend much time using digital display devices. Contact lens manufacturers are challenged to develop products that account for longer periods of time where blink rate is reduced and tear-film evaporation rate is increased, affecting both visual acuity and comfort. Two manufacturers recently introduced novel daily disposable contact lenses with high surface water content. The objective of the present study was to compare surface water characteristics before and after initial wear of recently introduced nesofilcon A and delefilcon A high surface water lenses with those of etafilcon A lenses.Patients and methodsTwenty healthy subjects wore each of the three lens types studied in a randomly determined order for 15 minutes. After each wearing, lenses were removed and the surface refractive index (RI) of each lens was immediately measured.ResultsThe mean RI of the unworn delefilcon A lens was 1.34, consistent with water content in excess of 80%. After 15 minutes of wear, the surface RI shifted to 1.43, consistent with its reported 33% bulk water content. In contrast, the mean surface RI of the nesofilcon A lens was 1.38, both initially and after 15 minutes of wear, and that of the etafilcon A lens was 1.41 initially and 1.42 after 15 minutes of wear.ConclusionThe surface of the delefilcon A lens behaves like a high water hydrogel upon insertion but quickly dehydrates to behave like its low-water silicone-hydrogel bulk material with respect to surface water content during wear, while both nesofilcon A and etafilcon A lenses maintain their water content during initial wear. The nesofilcon A lens appears unique among high water lenses in maintaining high surface and bulk water content during wear. This is important because changes in surface RI due to dehydration are reported to lead to visual aberration affecting user experience.

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Section: Discussionmentioning

confidence: 99%

Evaluation of surface water characteristics of novel daily disposable contact lens materials, using refractive index shifts after wear

Schäfer¹,

Steffen²,

Reindel³

et al. 2015

OPTH

View full text Add to dashboard Cite

show abstract

“…pressure over the SiHy with its Young's modulus. 20 For the SiHy studied the modulus varies between 0.025 MPa (DelA) 21 to 0.75 MPa (SenA). 22 This yields pressures in the range of 0.23-5.79 kPa, which agrees with the range (0.3-7 kPa) of upper eyelid pressures over contact lens surface reported for the human eye.…”

Section: Methodsmentioning

confidence: 99%

“…Similarly to linear reciprocating tribometry in the pin-on-disk setup the pressure exerted on the SiHy cannot be measured directly and can only be approximated by the Hertzian model which relates the pressure over the SiHy with its Young’s modulus. 20 For the SiHy studied the modulus varies between 0.025 MPa (DelA) 21 to 0.75 MPa (SenA). 22 This yields pressures in the range of 0.23–5.79 kPa, which agrees with the range (0.3–7 kPa) of upper eyelid pressures over contact lens surface reported for the human eye.…”

Section: Methodsmentioning

confidence: 99%

Relationships between the material properties of silicone hydrogels: Desiccation, wettability and lubricity

et al. 2020

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Silicone hydrogels (SiHy), represent composite matrices composed of hydrophobic gas permeable silicone (Si) rich core and a surface enriched with hydrophilic polymer moieties. Their utilization in contact lens design requires number of SiHy properties (hydration, wettability, lubricity) to be optimized for the challenging conditions at the ocular surface. Typical limitations in literature are that (i) these properties are studied in isolation, monitoring only one parameter but not the rest of them, and (ii) measurements are performed with hydrated samples immediately after removal from storage solutions. Here we study the simultaneous evolution of critical material properties (evaporative loss of water, water contact angle, coefficient of friction) of different SiHy subjected to continuous blink-like desiccation/rehydration cycling. SiHy with wetting agents incorporated in their core (narafilcon A, senofilcon A) were particularly susceptible to extended desiccation. Stenfilcon A, a material with only 3% bulk Si content maintained its performance for 4 h of cycling, and delefilcon A (80% surface water content) resisted extended 8 h of desiccation/rehydration runs. Strong correlation exists between the evolution of SiHy wettability and lubricity at ≥4 h of blink-like cycling. Understanding the interplay between SiHy properties bears insights for knowledge based design of novel ophthalmic materials.

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“…In other words, this lens is made with by a new technology called “three-layer moisture hydrogel”. 23 , 24 The silicone materials are naturally hydrophobic. Therefore, the internal silicone hydrogel is coated with a hydrogel-rich water to improve the wettability of the surface of the lens.…”

Section: Discussionmentioning

confidence: 99%

Adhesion of Pollen Particles to Daily Disposable Soft Contact Lenses

Mimura¹,

Fujishima²,

Uchio³

et al. 2021

OPTO

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Purpose Pollen and proteins attached to soft contact lenses (SCLs) exacerbate allergic conjunctivitis. The material of SCLs may affect the pollen adhesion to the SCLs. The factors associated with the number of pollen particles that are adherent to daily disposable SCL were investigated. Methods Pollen particles were experimentally exposed to the contact lens surface of 12 types of SCLs for 1 hour, and the SCLs were washed and rinsed with a physiological saline (n=10 for each SCL type). A total of 120 contact lenses were used in this study. The pollen particles attached to the SCL were observed and photographed under a microscope. The influence of the materials of the SCLs on the degree of pollen adhesion were investigated. Results The number of residual pollen particles attached to SCLs was in the range from 0–293/area of 200×200 µm. Percentage of pollen adhesion area of the surface of the SCL was in the range from 0.01% to 3.25%. There were significant differences in both the number and adhesion area of pollen particles among the 12 types of SCLs tested ( P <0.0001 and P <0.0001, respectively). The number of pollen particles adhered to SCLs was significantly higher in colored SCLs than clear SCLs (unpaired t -test, p<0.001). The portion of pollen adhesion area was the lowest in the silicone hydrogel SCLs made with delefilcon-A (0.01 ± 0.02%). Conclusion Pollen adhesion in daily disposable SCLs depends on the characteristics and materials of the SCLs and was high in colored SCLs and lowest in delefilcon-A silicone hydrogel SCL. These results suggest that colored SCLs are not preferred during pollen season.

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Structure–property relationship of delefilcon a lenses

Cited by 14 publications

References 0 publications

Evaluation of surface water characteristics of novel daily disposable contact lens materials, using refractive index shifts after wear

Evaluation of surface water characteristics of novel daily disposable contact lens materials, using refractive index shifts after wear

Relationships between the material properties of silicone hydrogels: Desiccation, wettability and lubricity

Adhesion of Pollen Particles to Daily Disposable Soft Contact Lenses

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