Effect of contact lens surface properties on comfort, tear stability and ocular physiology

Vidal-Rohr, Maria; Wolffsohn, James S.; Davies, Leon N.; Cerviño, Alejandro

doi:10.1016/j.clae.2017.09.009

Cited by 67 publications

(62 citation statements)

References 40 publications

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“…There have been some articles that have talked specifically about materials for contact lenses, which provided important insights at the time [32,33]. Other sources have discussed general bioavailable materials [34,35] and the properties of CL brands [33], with a lot of modern research being concerned about drug delivery using CLs [27,36,37,38]. This review brings together research specifically about the latest development of CL materials, and touches on details from a materials science perspective.…”

Section: Introductionmentioning

confidence: 99%

Contact Lens Materials: A Materials Science Perspective

2019

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More is demanded from ophthalmic treatments using contact lenses, which are currently used by over 125 million people around the world. Improving the material of contact lenses (CLs) is a now rapidly evolving discipline. These materials are developing alongside the advances made in related biomaterials for applications such as drug delivery. Contact lens materials are typically based on polymer- or silicone-hydrogel, with additional manufacturing technologies employed to produce the final lens. These processes are simply not enough to meet the increasing demands from CLs and the ever-increasing number of contact lens (CL) users. This review provides an advanced perspective on contact lens materials, with an emphasis on materials science employed in developing new CLs. The future trends for CL materials are to graft, incapsulate, or modify the classic CL material structure to provide new or improved functionality. In this paper, we discuss some of the fundamental material properties, present an outlook from related emerging biomaterials, and provide viewpoints of precision manufacturing in CL development.

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Section: Introductionmentioning

confidence: 99%

Contact Lens Materials: A Materials Science Perspective

2019

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“…in the SiHy core to the design of sophisticated CL surfaces with high water holding properties. The SiHy studied are chosen to present these distinct approaches [7][8][9] : narafilcon A (NarA), senofilcon A (SenA), stenfilcon A (StenA) and delefilcon A (DelA). NarA and SenA are SiHy materials with 48% and 38% water content, respectively, and no surface coating; polyvinylpyrrolidone based internal wetting agent is utilized instead.…”

Section: Introductionmentioning

confidence: 99%

“…Thus although no previous studies are reported in this regard, it can be expected that wettability may influence SiHy lubricity. 8,10,11 Secondly, the studies are commonly performed with fresh hydrated samples just removed from the blister solution, which neglects the alterations occurring in the CL due to accumulation of desiccation stress in the course of daily wear. 8 Therefore, the aim of the current study is to probe simultaneously the changes that occur in the water content, the wettability and the coefficient of friction (CoF) of these four diverse silicone hydrogels in the course of blink-like desiccation (10 s)/rehydration (1 s) cycling and to analyze the relationship between these properties at a time scale matching the duration of extended daily wear of the CL (0 i.e.…”

Section: Introductionmentioning

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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“…Instead, it is the higher coefficient of friction (CoF) in contact lens compared to an ocular surface without contact lens that may be a major contributor for the difference in LWE. 57,58 CoF is defined as the relationship of friction between two interfacing surfaces, with contact lens CoF determined by material, as well as deposits that develop during wear. 13 The importance of contact lens CoF is highlighted by studies that suggest that its increase may be associated with increased contact lens discomfort and corneal staining.…”

Section: 13mentioning

confidence: 99%

“…13 The importance of contact lens CoF is highlighted by studies that suggest that its increase may be associated with increased contact lens discomfort and corneal staining. 13,57,58 It has also been found that LWE can develop shortly after individuals start wearing contact lenses. 43 It is therefore conceivable that a regular and smooth surface (either contact lens or cornea) that comes in contact with the lid wiper is a prerequisite for a healthy lid wiper.…”

Section: 13mentioning

confidence: 99%

The Relationship of Lid Wiper Epitheliopathy to Ocular Surface Signs and Symptoms

Yeh

Leung

et al. 2018

Invest. Ophthalmol. Vis. Sci.

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PURPOSE. There has been interest in determining whether lid wiper epitheliopathy (LWE) plays a key role in causing ocular discomfort. Conflicting reports have made it difficult to discern whether LWE is more prevalent in certain populations, what characteristics are associated with its severity, and what its role is in symptomology. This cross-sectional study on a large and diverse population attempts to answer these questions.METHODS. Subjects were asked to complete questionnaires related to dry eye and to ocular discomfort. A comprehensive set of ocular surface parameters were assessed, including LWE length and width, tear-film lipid layer thickness, fluorescein tear breakup time (FTBUT), lidparallel conjunctival folds (LIPCOF), and corneal staining. RESULTS.A total of 287 subjects participated in the study. LWE was observed in 45% of the study cohort and was twice as prevalent in Asians than non-Asians (P < 0.005). LWE was more likely to present in contact lens wearers than non-contact lens wearers (P ¼ 0.03). Decreased FTBUT was associated with increased LWE length and width (P < 0.005 and P ¼ 0.01, respectively), although only a small effect size was noted. Presence of LIPCOF was linked with a 0.25-grade increase in LWE width (P ¼ 0.01). Only LWE width was associated with greater symptoms in contact lens wearers.CONCLUSIONS. LWE was associated with decreased tear-film stability, contact lens wear, lid anatomy, and LIPCOF. LWE was not associated with symptoms in non-contact lens wearers. LWE width was associated with greater symptoms in contact lens wearers but was only clinically significant with moderate to severe LWE width.

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Effect of contact lens surface properties on comfort, tear stability and ocular physiology

Abstract: As previously hypothesised, enhancing the physical surface properties of a soft contact lens improves subjectively rated wearer comfort, which, in turn, should result in reduced contact lens discontinuation.

Cited by 67 publications

References 40 publications

Contact Lens Materials: A Materials Science Perspective

Contact Lens Materials: A Materials Science Perspective

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

The Relationship of Lid Wiper Epitheliopathy to Ocular Surface Signs and Symptoms

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