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Contact lense industryThe contact lens (CL) industry and market have displayed a high level of dynamism in the past few decades, and have evolved into a rapidly changing field in which science and everyday practice constantly interact, not only through broadening of material and product portfolio, but through innovative therapeutic and diagnostic solutions as well. Stable market growth with numerous rearrangements in different product segments is constantly taking place, mainly stirred by innovative material and optical design. The standardly used hydrogel materials are being rapidly replaced by silicone doped hydrogel materials. The analyses of customer CL usage and satisfaction indicate continued market growth in future, however with many changes in product profile and significant increase in multifocal and daily disposable lenses market share. The main impulse behind the dynamism of CL industry stems from results of scientific and technological improvements, which are enhancing medical field and reminding us that the focal point of sustainable development lies in scientific investigations. Contact lenses in present, past and futureThe technology of materials used in CL production has improved vastly in the past decades starting from glass and moving to polymer based materials (PMMA) with, eventually, major steps being taken in including hydrogel and doped-hydrogel based materials, shifting the functionality of CLs from rigid gas-impermeable (RGP) to soft gas-permeable materials represented by silicone hydrogel materials that are now in use. This chapter will focus on multimodal applied research of rigid gas-permeable contact lenses (CL) that are manufactured from fluorosilicone acrylate based material. Our multimodal research comprises measurement of intermolecular interactions on the basis of optical, mechanical, morphological and magnetic properties of CL material. The role of our research in such a complex system of CL industry was introduction of new diagnostic modalities through improved material characterization. In the course of last decade, scientists have developed different possibilities of "on eye"CL application that are not related to its optical capabilities for which they were invented in the first place -correcting eye's refractive error. Furthermore, improvement in CL material manufacturing, both soft and rigid gas permeable, are mostly directed towards increasing oxygen permeability and wearing comfort. Rarely today, CL producers are dedicated to 15 www.intechopen.com 2 Will-be-set-by-IN-TECH improving CL material properties for the purpose of enhancing the quality of vision, on the contrary, by doping them with silicone, for example, the optical properties become even worse. Apart from it's properties to correct eye's refractive anomaly (dioptric power), the most frequent factors influencing quality of vision while wearing RGP CL are those related to the fact that visible light, on it's way to the eye's "perception area"-the macula, must pass through CL material itself, and all it's characte...

Abstract:Tears provide moisture and supply oxygen and other important nutrients to the cornea, mechanically trap and flush out foreign bodies and chemicals and keep the surface of cornea smooth and optically clear. Additionally, during blinking, tear film lubricates the friction area between lids and ocular surface. Tear film contains an aqueous layer that includes water, bacteriostatics, proteins and salt. Contact lens wearers often suffer from dry eyes. These changes in the tear film are caused by contact lens design, surface, material and applied solution for conditioning. In case of application of gas-permeable contact lens, the multi-factorial problem of tear film stability and therefore, maintaining of lubrication are main goals in the ongoing investigation. This paper focuses on applied research of the response of material's surface roughness quality to retain tear film on the micro and nanolevel by using a gliding-box method for lacunarity analysis. The topology of contact lens surface with tear film as the lubricant was studied from the point of view of the water as primary consistent in its bulk liquid form, as well as confined water film organized into layers in a nanometer-sized channel. Contact lens surface topology observed on micro and nano-scale indicates different lubrication behavior of aqueous tear layer. As opposed to bulk water as a disordered medium in micro scale that flows very readily, nano-water demonstrates the behavior effectively like some phases of liquid crystals.

The aim was to develop new materials that would, after appropriate machining processes, improve the surface roughness and wettability of contact lenses. The samples used in this investigation were standard rigid gas-permeable (RGP) SOLEKO contact lenses, made of poly-MMA-co-siloxy silane methacrylate material (known under the commercial name SP40 TM ), and its modifications by adding three nanomaterials: fullerene C60 (designated as SP40-A), fullerol C60(OH)24 (designated as SP40-B) and methformin hydroxylate fullerene C60(OH)12(OC4N5H10)12 (designated as SP40-C). Both atomic force microscopy (AFM) and magnetic force microscopy (MFM) were used to measure the topography and gradient of the magnetic field of the nanophotonic materials and the reference samples. According to the magnetic properties of all the materials yielded by MFM it can be concluded that adding fullerene and its derivatives certainly reduces the spectrum of the phase shifts angle by almost 50 %, which increases the paramagnetic characteristics of the nanophotonic material. The positive result of nanophotonic materials characterization is the fact that the roughness parameter values for all of these materials, are lower than those for the basic material. A surface lacunarity analysis, based on in-house procedures for determining the lacunarity value of contact lens surfaces, confirms the influence of surface topology on the tear film volume distribution and, consequently, the contact lens' surface lubrication. The presence of carbon nanomaterials, according to the surface roughness parameters, are improved for rigid gas-permeable (RGP) contact lenses made from nanophotonic polymer materials compared to those produced from the basic material. Keywords: fullerenes, polymer materials, surface roughness, atomic force microscopy, magnetic force microscopy Namen je bil razviti nov material, ki bi po ustrezni strojni obdelavi zmanj{al hrapavost povr{ine in omo~ljivost kontaktnih le~. Vzorci, uporabljeni v tej raziskavi so bile standardne toge, za plin prepustne (RGP) SOLEKO kontaktne le~e, narejene iz poli-MMA-ko-siloksi silan metakrilatnega materiala (s komercialnim imenom poznanega SP40 TM ) in njihove modifikacije z dodatkom treh nanomaterialov: fulerena C60 (ozna~enega kot SP40-A), fulerola C60(OH)24 (ozna~enega z SP40-B) in metformin hidroksilat fulerena C60(OH)12(OC4N5H10)12 (ozna~enega z SP40-C). Uporabljeni so bili: mikroskopija na atomsko silo (AFM), mikroskopija na magnetno silo (MFM) za merjenje topografije in gradient magnetnega polja nanofotonskih materialov in referen~nih vzorcev. Skladno z magnetnimi lastnostmi vseh materialov, dobljenih z MFM, je mogo~e zaklju~iti, da dodajanje fulerenov in njegovih izpeljank, mo~no zmanj{a spekter kotov faznega premika za skoraj 50 %, kar pove~a paramagnetne zna~ilnosti nanofotonskih materialov. Pozitivni rezultati karakterizacije nanofotonskih materialov so, da so vrednosti parametra hrapavosti pri vseh teh materialih ni`je kot pri osnovnem materialu. Analiza povr{inske razporeditve praznin, na osnovi...

Fractal analysis was used in previous authors' researches for characterizations of grinded ceramics surface textures by surface profile fractal dimension. In this paper the 'skyscrapers' method was chosen for calculating fractal dimension of surface, using the image processing toolbox, as well as a custom-developed algorithm of Matlab environment. This method entails recording the surface as an image, by using a scanning probe microscope. In the given contact lens case, fractal dimension values confirm changes of the surface roughness during the cleaning and wearing processes. Examination of real surface roughness could provide comparison and functional behavior prediction