• Journal of the Korean Chemical Society
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• v.56 no.1
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• pp.169-174
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• 2012

• Journal of the Korean Chemical Society
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• v.55 no.2
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• pp.308-312
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• 2011

• Journal of Korean Ophthalmic Optics Society
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• v.1 no.1
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• pp.57-63
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• 1996

The microbial contamination in contact lens care systems and conjunctivas of 40 asymptomatic cosmetic soft contact lens wearers was investigated. Patient ages ranged from 19 to 27(mean:22), most of them have used hydrogel contact lenses for less than 1 year, and the ages of lens cases were 1 weeks ~ 3 months (43 %) or 4~6 months (52%). Twenty-seven patients (67%) chemically disinfected their lenses and 8(20 %) used hydrogen peroxide, and 5 used heat to disinfect. Fourteen patients used commercial non-preserved saline, and 26(65%) were using commercial preserved saline. Sixty-two percent of the patients had bacterial contamination of lens case, and 17% had conjunctival contamination. The bacterial contamination rate was highest in lens cases, followed by unpreserved salines, disinfecting chemicals(non-hydrogen peroxide), and conjunctivas. The fungal contamination rate of cases and conjunctivas was 67% and 15%, respectively, and lens case, unpreserved saline, and conjunctiva seemed more susceptible to contamination. The use of hydrogen peroxide for disinfection rather than chemical disinfection was associated remarkabley with decreased contamination of solution itself, and there was no significant difference in contamination rates between hydrogen peroxide care system and other disinfecting systems. Five of lens cases(13%) and 2 conjunctivas(5%) were contaminated with Pseudomonas aeruginosa, and Candida albicans were isolated from 11cases (27%) and 5 conjunctivas (12%). Of the organisms that were contaminated lens cases and conjunctivas, Pseudomonas aeruginosa, Escherichia coli, Candida albicans, and Aspergillus fumigatus were isolated from lens cases, whereas Pseudomonas aeruginosa, Candida albicans, and Aspergillus fumigatus were recorvered from conjunctivas. Fortunately all of the these tested samples showed 0% of Acanthamoeba in this investigation.

• Journal of Korean Ophthalmic Optics Society
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• v.18 no.3
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• pp.261-270
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• 2013

Purpose: Adsorption properties of lysozyme and albumin according to physiochemical properties of commercial contact lens classified with the FDA categories and a contact lens fabricated in the laboratory were investigated. Methods: The contact lens were prepared using HEMA(2-hydroxyethyl methacrylate) and TRIM(3-(trimethoxysilyl) propyl methacrylate) in a cast mold. Artificial tears containing lysozyme and albumin were prepared. We measured the amounts of protein adsorbed on the each lenses with varying adsorbed time (48 hour) and the pH range (6, 6.8, 7.4, 8.2, 9) of artificial tear. Amount of the proteins absorbed on the contact lenses were measured by using HPLC. Results: Time to reach the equilibrium of protein adsorption for silicone hydrogel lens was taken longer than hydrogel lens. The amount of adsorbed both lysozyme and albumin at equilibrium were greater for the hydrogel lens than the silicone hydrogel lens, and larger for the ionic lens than the non-ionic lens. Lysozyme was more adsorbed on the higher water content of contact lens, whereas albumin was more adsorbed on the lower water content of contact lens. Only lysozyme was adsorbed on the Group IV hydrogel lens of ionic higher water content. The adsorption of protein on contact lens increased with pH of artificial tears as close to the isoelectric point of each protein. Conclusions: The adsorption amount of lysozyme is more affected by the ionic strength of the contact lens surface than the water content of contact lens. Albumin adsorption is more affected by water content than the ionic strength of the contact lens surface. For the adsorption of proteins on the silicone hydrogel lens, the pore size, determined both by the number of Si atoms and the chemical structure of the silicone-containing monomers, as well as the polarity of contact lens should be also considered.

• Journal of the Korean Chemical Society
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• v.61 no.3
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• pp.97-103
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• 2017

In this study, the functional hydrogel ophthalmic lens containing tungsten oxide nanoparticles, 2,4-dihydroxy benzophenone and 2-hydroxy-4-(methacryloyloxy) benzophenone were manufactured. HEMA (2-hydroxyethyl methacrylate), MMA (methyl methacrylate), AA(acrylic acid), the cross-linker EGDMA (ethylene glycol dimethacrylate), the initiator AIBN (azobisisobutyronitrile) and the functional additives including tungsten oxide nanoparticles, 2,4-dihydroxy benzophenone, and 2-hydroxy-4-(methacryloyloxy) benzophenone were used respectively. The measurements of water content and refractive index of the sample was decreased and increased, respectively. And also, the UV transmittance of produced lens containing 2,4-dihydroxy benzophenone, 2-hydroxy-4-(methacryloyloxy) benzophenone and tungsten oxide nanoparticles was measured. Based on the results of this study, it is judged that the performance improvement increased over time when 2-hydroxy-4-(methacryloyloxy) benzophenone was used as an additive, while the use of tungsten oxide nanoparticles influenced on blue-ray-blocking effect of the hydrophilic lens.

• Journal of the Korean Chemical Society
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• v.56 no.2
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• pp.303-308
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• 2012

• Journal of the Korean Chemical Society
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• v.58 no.5
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• pp.490-495
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• 2014

• Journal of Korean Ophthalmic Optics Society
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• v.15 no.4
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• pp.347-353
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• 2010

Purpose: An in vitro study was conducted to compare the lipid cleaning efficacy of care solutions on balafilcon A silicone hydrogel (SiHy) lens. Methods: Lipid spoilation was performed by incubating balafilcon A SiHy lenses in phosphate buffered saline (PBS) containing oleic acid, oleic acid methyl ester and cholesterol. Spoiled contact lenses rinsed with PBS were cleaned with surfactant cleaner, alcohol containing cleaner and multipurpose solution (MPS) respectively and repetitive spoilation and cleaning was conducted up to 14 times. To observe the cleaning effect of ultrasonic wave on the lipid deposit, each spoiled lens was ultrasonicated and then compared with non-sonicated lens. Lipids deposit on the contact lenses was extracted by methanol:chloroform (1:1, v/v) solution. High performance liquid chromatography was used to analyze and quantify lipid deposit extracts. Results: The effectiveness of alcohol containing surfactant cleaner on the lipid deposits was better than that of surfactant cleaner and MPS, and the cleaning efficacy was significantly higher in the ultrasonic wave treated group. Lipid deposits were not removed completely by contact lens care solutions so that lipid deposits increased continuously and cumulatively. Conclusions: The cleaning efficacy of contact lens care solutions was not satisfactory to remove lipid deposits on the SiHy lens that new cleaning products specially designed for SiHy lenses are needed to develop.

• Journal of Korean Ophthalmic Optics Society
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• v.19 no.1
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• pp.111-120
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• 2014

Purpose: This study was to investigate changes in the thickness of cornea, curvature of cornea, and aberration depending on the water contents, materials, and refractive power of contact lens. Methods: The differences in the corneal thickness between pre- and post-wearing the lenses were compared using 5 kinds of lenses. The changes in the corneal thickness, the curvatures of the anterior and posterior cornea, and high order aberration (HOA) before and after wearing the lenses were investigated at the center of the cornea, and the different distance and the direction away from the center of the cornea. For the equipments of measurement, ORB ScanII (Bausch & Lomb Inc, ver 3.14) was used to measure the corneal topography and thickness, and Zywave (Bausch & Lomb Inc, ver 5.20) was used to analyze the high order aberration. Results: Five (S1, S2, S3, T1, T2) of the lens was used for this study, excluding the lens T2 lens has four lenses and the thickness of the corneal shape, but the impact is minimal. In the case of the hydrogel soft contact lenses (T2 lens) with low oxygen permeability, the corneal thickness showed distinct increasing patterns. The high order aberration and coma aberration were most changed in the silicon hydrogel toric lens, while the depth of anterior was most changed in the hydrogel toric lens. Conclusion: Among the 5 kinds of contact lenses with different water contents, materials, and refractive power used for this study, the corneal shape change was small for the lenses with an oxygen permeability (Dk) of more than 28, and the largest for the lenses with a very low oxygen permeability.

• Journal of Korean Ophthalmic Optics Society
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• v.12 no.4
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• pp.43-54
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• 2007

Silicone hydrogel contact lenses developed as a continuous-wear modality are now used as a daily-wear contact lenses. The purpose of this study was to investigate the clinical performance in a group of successful long-term wearers of conventional hydrogel contact lenses when refitted with daily wear $O_2OPTIX$ silicone hydrogel lenses. Sixty-two wearers ($30.7{\pm}19.9$ months of prior lens wear) among sixty-five soft lens wearers refitted with $O_2OPTIX$ silicone hydrogel lenses were participated in this study finally. Subjective symptoms were scored and objective signs were graded using CCLRU scales during the study period. 98% of subjects were successfully refitted with the one base curve of $O_2OPTIX$, and 33.9% of subjects were needed more or less lens powers compared with their habitual lenses. Subjects reported a concurrent reduction in dryness, redness and tiredness compared with their habitual lenses and both subjective and objective evaluations showed that dryness, tiredness, itchiness, bulbar and limbal hyperemia were decreased and significantly decreased particularly for those subjects with greater baseline symptoms (p<0.0001). But corneal staining was increased and was seen in many subjects during the study (p<0.0001). Refitting existing soft contact lens wearers with silicone hydrogel contact lens could result in a decreased in dryness, redness and tiredness, particularly more effective for those subjects with greater baseline of those symptoms. When patients using conventional hydrogel materials switch to a silicone hydrogel material, the potential for increased corneal staining should be considered and over-refraction should be needed to give a best vision.