• Journal of Korean Ophthalmic Optics Society
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• v.17 no.1
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• pp.27-35
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• 2012

Purpose: The present study was conducted to compare any difference caused by pigmentation in the centrations and movement patterns on the cornea between circle and soft contact lens with identical material and parameters during lens wearing. Methods: Soft and circle contact lenses with identical material and parameters were applied to twenty eyes with normal tear volume for 3 hrs a day during a total of 5 days and then their lens centrations, the moving distances and rotations by repeat blinking were compared. Results: The lens centration beyond the fitting criteria was shown in initial wears of both soft contact lens and circle contact lens. However, the centration of soft contact lens was changed to the pupil center for being suitable to the fitting criteria with longer wearing time. On the other hand, the decentration of circle contact lens in the horizontal direction was still presented even with longer wearing time. The moving distances of soft contact lens and circle contact lens decreased with the expand of lens wearing but were not significantly different between total wearing period and daily wearing time. The rotation of circle contact lens by repeat blinking was significantly different from that of soft contact lens even when the wearing period was extended. Conclusions: We revealed that the lens centration and movement of circle contact lens on cornea were different from those of regular soft contact lens resulting in bigger difference with the expand of wearing period in the study.

• Journal of the Korean Chemical Society
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• v.64 no.6
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• pp.354-359
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• 2020

This research was conducted to analyze the compatibility of used monomers and produce the high functional contact lens material containing silicone monomers. Silicone monomer (Sil-OH), Trimethylsilylmethacrylate (TSMA) were used as additives for the basic combination of Polyhedral Oligomeric Silsesquioxane (POSS), methyl methacrylate (MMA) and methyl acrylate (MA). And also, the materials were copolymerized with ethylene glycol dimethacrylate (EGDMA) as the cross-linking agent, AIBN (thermal polymerization initiator) as the initiator. It is judged that the fabricated lenses of all combinations are optically excellent and thus used monomers have good compatibility. Measurement of the optical and physical characteristics of the manufactured hydrophilic lens material were varied in each case. Especially TSMA with POSS increases the oxygen permeability and Sil-OH with POSS increases the wettability by the addition of Sil-OH. These materials were considered to have compatibility each other, so it can be used in functional contact lens material.

• Journal of Korean Ophthalmic Optics Society
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• v.20 no.2
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• pp.151-156
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• 2015

Purpose: This study has been compared the degree of corneal edema arising from the material of the lens after wearing the recommended wearing time for the contact lens. Methods: For the study, 43 adults of 77 eyes who did not use drugs and have not any disease participated. Three types of lenses including narafilcon A, HEMA, and silicone hydrogel material regular replaceable lenses were used. Central corneal thickness was measured before and after 8 hours from wearing lenses using Pentacam. The degree of corneal edema was determined by the difference before and after wearing. Results: The average corneal edema of narafilcon A, HEMA material lens, and silicone hydrogel material regular replaceable lens were $2.36{\pm}6.15{\mu}m(Mean{\pm}SD)$, $23.61{\pm}10.71{\mu}m$, $18.25{\pm}8.64{\mu}m$, respectively. The central corneal thickness after wearing narafilcon A was not statistically significant with the central corneal thickness before wearing the lens. Central corneal thickness before and after wearing HEMA material lens and silicone hydrogel material regular replaceable lens were statistically significant. Conclusions: The amount of corneal edema induced by silicone hydrogel material regular replaceable lens was no statistically significant difference to the amount of corneal edema induced by HEMA material lens, but there was significant difference to narafilcon A. Therefore, it is judged to be careful not to exceed the recommended wearing time depending on the composition of the contact lens material.

• Korean Journal of Materials Research
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• v.28 no.8
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• pp.452-458
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• 2018

This research is conducted to create a functional hydrogel ophthalmic lens containing nanoparticles. Carbon nanoparticles and PEGMEMA are used as additives for the basic combination of HEMA, MA, and MMA, and the materials are copolymerized with EGDMA as the cross-linking agent and AIBN as the thermal initiator. The hydrogel lens is produced using a cast-mold method, and the materials are thermally polymerized at $100^{\circ}C$ for an hour. The polymerized lens sample is hydrated in a 0.9 % saline solution for 24 hours before the optical and physical characteristics of the lens are measured. The refractive index, water content, contact angle, light transmittance, and tensile strength are measured to evaluate the physical and optical characteristics of the hydrogel lens. The refractive index, water content, contact angle, UV-B light transmittance, UV-A light transmittance, visible light transmittance, tensile strength and breaking strength of the hydrogel lens polymer are 1.4019~1.4281, 43.05~51.18 %, $31.95{\sim}68.61^{\circ}$, 21.69~58.11 %, 35.59~84.26 %, 45.85~88.06 %, 0.1075~0.1649 kgf and 0.1520~0.2250 kgf, respectively. The results demonstrate an increase in refractive index, tensile strength and breaking strength and a decrease in contact angle and light transmittance. Furthermore, the visible light transmissibility is significantly increased at PEG 10 %. It is clear that this material can be used for high-performance ophthalmic lenses with wettability, ultraviolet ray blocking effect, and tensile strength.

• Journal of Korean Ophthalmic Optics Society
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• v.20 no.2
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• pp.125-131
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• 2015

Purpose: The effect of pigmentation in circle contact lens on lens wearers' tear film stability was investigated in this study. Methods: Non-invasive tear film break-up times of 54 normal eyes before and after lens wearing in twenties and the portion of first tear breakup were measured. The frontal and back surface roughness of circle contact lens was further observed with a scanning electron microscope. The clear lens which was made of hilafilcon B and circle contact lenses which were made of hilafilcon B, polymacon and copolymer of HEMA NVP were tested. Results: Non-invasive tear film breakup time was significantly reduced compared with it before lens wearing. In some case, statistically significant difference in tear film breakup time was also observed between circle contact lenses. The tear file break-up was usually early started in lower than upper portion, and in temporal than nasal portion although there was variation in the lens material. The tear film break-up of circle contact lenses made of hilafilcon B was more commonly observed in peripheral portion(pigmented area) compared with clear contact lens made of same material. Conclusions: The present study revealed that the stability of tear film was affected by wearing circle contact lens and the result seems to be used as the basis for the problem solving that can occur due to the pigmentation when wearing circle contact lens.

• Journal of Korean Ophthalmic Optics Society
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• v.11 no.2
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• pp.143-149
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• 2006

The purpose of this study is synthesizing silicone polymer which is used the material of contact lens and solving the problems of water content and light transmittance for gas permeable contact lens. We used NVP, MMA, HEMA monomer for polymerization and EGDMA as cross linking regent. Also, we polymerized with a several formulation arrangement for the best condition as contact lens. After that. we measured water content and light transmittance by each sample which was polymerized. We polymerized the silicone polymer which is simultaneously pursued by the transparent and water content of the material and measured their physical nature of each sample on this study.

• Journal of Integrative Natural Science
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• v.9 no.4
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• pp.249-254
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• 2016

This study evaluated the physical and optical characteristics of hydrophilic ophthalmic polymer with addition of 2-methacryloyloxyethyl phosphorylcholine in the basic hydrogel ophthalmic lens material, and in particular, the utility of 2-methacryloyloxyethyl phosphorylcholine as an ophthalmic contact lens material for ophthalmologic devices was investigated. In this study 2-methacryloyloxyethyl phosphorylcholine were used as additives. For the preparation of hydrogel lens 2-hydroxyethyl methacrylate, methyl methacrylate, acrylic acid and a cross-linker EGDMA were copolymerized in the presence of AIBN as an initiator. The physical properties of the produced polymers were measured as followings. The refractive index of 1.433~1.393, water content of 35.95~53.16%, contact angle of $70.6{\sim}51.24^{\circ}$, UVB transmittance of 81.2~82.4%, UV-B transmittance of 81.2~82.4% and visible transmittance of 91.4~92.2% were obtained. Also, in case of protein absorption, the measurement showed that absorbance of Reference and MPC-10 sample was 0.2598 and 0.2250 respectively. Based on the results of this study, ophthalmic lens material containing 2-methacryloyloxyethyl phosphorylcholine is expected to be used usefully as a material for high wettability and inhibitor of protein adsorption for ophthalmic hydrogel lens.

• Journal of Korean Ophthalmic Optics Society
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• v.13 no.3
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• pp.45-50
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• 2008

Purpose: A soft contact lens was manufactured by adding naringin known as natural anti-bacterial material to resin solution. With solution eluted from manufactured contact lens, we examined its optical properties, physical and chemical states of naringin in the polymer, and elution properties. Methods: The soft contact lens with naringin was synthesized by bulk polymerization method. IR spectrum and HPLC were used to define the bonding type of naringin itself in the soft contact lens contained naringin, elution process of naringin to the saline solution, and the amount of naringin solution eluted from the lens with elapsed time. Results: Naringin was continuously eluted with constant concentration from the soft contact lens for about a month and the structure ofnaringin which is eluted was as same as before it was added to resin solution. Any change in optical properties such as transmittance couldn't be found. Bonding state and the structure of naringin in contact lens were explained with IR spectrum and HPLC results. Conclusions: In the contact lens with naringin, naringin remained in the contact lens bonding with weak hydrogen bonding and/or van der Waals force between naringin and polymer. Naringin was continuously eluted from the contact lens contained naringin during about 1 month. Even after 1 month, it showed that the concentration of the naringin eluted was approximately 10 ppm in a day. From the results, adding naringin to the soft contact lens resin is very effective method for manufacturing the soft contact lens which has anti-bacterial function for a period of time.

• Journal of Korean Ophthalmic Optics Society
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• v.21 no.2
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• pp.109-117
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• 2016

Purpose: The study was aimed to figure out the effect of materials and pigmentation of soft contact lens on the adherence of Staphylococcus aureus upon soft contact lenses deposited with tear components. Methods: The number of adherent S. aureus on clear and circle soft contact lenses made of etafilcon A, hilafilcon B, nelfilcon A was measured before and after incubation in artificial tear. Furthermore, the denaturalization level of tear protein with time after incubation in artificial tear was estimated by electrophoresis. Results: The adherence of S. aureus was significantly different according to the lens materials. The pattern of bacterial adherence on clear and circle contact lenses was different. That is, the adherent amount of S. aureus was somewhat larger on circle lens made of etafilcon A however, amount on circle lenses made of hilafilcon B and nelfilcon A was 89.3% and 71.3% of the number on clear lenses. When the tear protein was deposited on contact lenses, the number of adherent bacteria decreased and its degree was varied according to the lens material. The degree of decrease was the biggest in clear soft lens made of etafilcon A. Anti-bacterial effect of tear protein decreased with time after deposition of tear protein on soft contact lens and the amount of lysozyme also decreased. The reduction of anti-bacterial effect and quantity of lysozyme was different according to contact lens materials and pigmentation. Conclusions: It was revealed that the adherence of S. aureus depends on contact lens materials and pigmentation, and the specification of lens material affects more on adherence of S.aureus than pigmentation. It was further figured out the denaturalization level of anti-bacterial protein on soft contact lens varies according to lens materials and pigmentation, which produces an effect on the quantity of bacterial adherence.

• Journal of Korean Ophthalmic Optics Society
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• v.17 no.2
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• pp.233-239
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• 2012

Purpose: In the study, the change of protein and lipid deposits on soft contact lens by drinking was investigated. Methods: Fifty male subjects wearing soft contact lens were surveyed whether they felt any discomfort induced by drinking or not. Further, 32 male subjects who has no ocular disease drank 190 mL alcohol. The protein and lipid deposits on soft contact lens (etafilcon A material) of subjects were measured after 4 hours later and compared with those of non-drinking subject. Results: When subjects drink alcohol with soft contact lens on, 58% of subjects answered they experienced the change of lens awareness such as stiffness, blurry sight, dryness and so on. The protein deposit on soft contact lens increased an average of $59.3{\mu}g/lens$ by drinking and the case of more than double in protein deposit was reached in 9 eyes. However, the protein deposited on soft contact lens was lysozyme which was unchanged by drinking. The amounts of cholesterol and methyl oleate after drinking were 85.5% (p=0.25) and 52.6% (p=0.002) of non-drinking's indicating some change of lipid deposit on soft contact lens by drinking. Conclusions: The results showed the composition of protein and lipid deposited on soft contact lens was changed due to drinking. Thus, it is suggested that wearing soft contact lens when drinking might be one of the reasons to feel discomfort.