Role of the Water Gradient Structure in Inhibiting Thin Aqueous Layer Break in Silicone Hydrogel-Soft Contact Lens

It is popular to wear the contact lens nowadays. Also, the output value of the contact lens is estimated more than 4 billion NT dollar every year. Because the phenomena of the contact lenses are very complicated, the relevant mechanisms are not well understood. Thus, the security of contact lens needs to be further investigated. In the lubricated mechanism of the contact lens, there is a layer of tear between the contact lens and cornea. The contact lens’ behavior is akin to that of a slider bearing. The lens represents the slider, the eye plays the role of the stationary pad, and the tear film is the lubricant. Hence, hydrodynamics and contact mechanisms of a contact lens are quite a fascinating subject that is relevant to the science of tribology. In the paper, the lubrication mechanisms include the partial hydrodynamic lubrication (contact lens roughness), contact mechanics and Newtonian fluid mechanics have been established. The parameters of roughness, flow factor, tear film geometry, and hydrodynamic pressure distribution are discussed. The developed technology increases the safety of contact lens.

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Performance of Three Multipurpose Disinfecting Solutions with a Silicone Hydrogel Contact Lens

BioMed Research International ◽

10.1155/2015/216932 ◽

2015 ◽

Vol 2015 ◽

pp. 1-13 ◽

Cited By ~ 4

Author(s):

Nery García-Porta ◽

Laura Rico-del-Viejo ◽

Helena Ferreira-Neves ◽

Sofia C. Peixoto-de-Matos ◽

Antonio Queirós ◽

...

Keyword(s):

Contact Lens ◽

Clinical Performance ◽

The Other ◽

Soft Contact ◽

Silicone Hydrogel ◽

Soft Contact Lens ◽

Comfort Rating ◽

Analogue Scales ◽

Lens Wear

Purpose. To evaluate the clinical performance of a silicone hydrogel (Si-Hy) soft contact lens (CL) in combination with three different multipurpose disinfecting solutions (MPDSs).Methods. This was a prospective, randomized, single-masked, crossover, and comparative study in which 31 habitual soft CL wearers were randomly assigned to one of the three MPDSs (Synergi, COMPLETE RevitaLens, and OPTI-FREE PureMoist) for 1 month with a 1-week wash-out period between each exposure. All subjects were successfully refitted with a Si-Hy CL (Biofinity). Subjects were then scheduled for follow-up visits after 1 month of lens wear, being evaluated at 2 and 8 hours after lens insertion. Visual Analogue Scales (VAS) were used to gauge comfort rating.Results. The tarsal conjunctiva showed a significantly different degree of lid redness between the MPDSs at the 2-hour visit (P<0.05, Kruskal-Wallis test), being lower for COMPLETE RevitaLens compared to the other two MPDSs (Mann-WhitneyUtest). Furthermore, a significantly different degree of lid roughness at the 8-hour visit was seen (P<0.05, Kruskal-Wallis test), being higher for Synergi (Mann-WhitneyUtest). The subjective comfort was similar with the three MPDSs.Conclusion.Tarsal conjunctival response should be also considered in the context of the clinical performance of MPDs at the ocular surface.

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