• Journal of the Optical Society of Korea
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• v.19 no.2
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• pp.182-187
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• 2015

This paper presents a new graphical method for selecting a pair of optical glasses to simultaneously achromatize and athermalize an imaging lens made of materials in contact. An athermal glass map that plots thermal glass constant versus inverse Abbe number is derived through analysis of optical glasses and plastic materials in visible light. By introducing the equivalent Abbe number and equivalent thermal glass constant, although it is a multi-lens system, we have a simple way to visually identify possible optical materials. Applying this method to design a phone camera lens equipped with quarter inch image sensor having 8-mega pixels, the thermal defocuses over $-20^{\circ}C$ to $+60^{\circ}C$ are reduced to be much less than the depth of focus of the system.

• Journal of Korean Ophthalmic Optics Society
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• v.10 no.4
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• pp.261-266
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• 2005

Quaternary ammonium compounds(QACs) are some of the most commonly used antimicrobials. Antimicrobial polymers have been used as biomedical devices. In this Study, We synthesized new methacrylate monomers including quaternary ammonium moieties for preparation of contact lens, And also, we tested for antimicrobial activities against S. aureus, E. coli and P. aeruginosa. They showed much higher antimicrobial activities against all than the polymers of no including quaternary ammonium.

• Journal of Integrative Natural Science
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• v.11 no.1
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• pp.39-43
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• 2018

Poly(hydroxyethyl methacrylate)-based hydrogels were surface-functionalized with spiropyran (SP) derivatives to obtain photochromic contact lenses. The contact lens reversibly changes from colorless to purple as response to UV light since colorless ring-closed SP state converts to purple ring-opened merocyanine (MC) state under UV light irradiation. The purple contact lens emits red light at 640 nm. Importantly, the presence of SP segments did not significantly affect the equilibrium water content (EWC) of the lens. SP-functionalized hydrogel lenses may find potential applications in developing light-adaptive ophthalmic materials.

• Prospectives of Industrial Chemistry
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• v.18 no.6
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• pp.21-28
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• 2015

콘택트렌즈는 시력 보정의 목적으로 개발되기 시작하여 최근에는 다양한 목적을 위해 이용되고 있다. 특히, 콘택트렌즈를 IT, NT, BT와 융합하여 질병 진단을 목적으로 이용하는데 관심이 높아지고 있다. 본지에서는 콘택트렌즈의 재료와 최근 주목받고 있는 진단용 콘택트렌즈와 소재에 대해 소개하고 앞으로 전망에 대해 논하였다.

• Journal of Korean Ophthalmic Optics Society
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• v.19 no.2
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• pp.153-162
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• 2014

Purpose: This study was assessed to investigate the change of subjective and/or objective symptoms and the light transmittance of lens caused by the use longer than recommended wearing time of daily disposable circle contact lenses (circle lens) in dry eyes. Methods: Three daily disposable circle lenses made of etafilcon A, hilafilcon B, and nelfilcon A were applied on 30 dry eyes with smaller tear volume than normal eyes in their twenties free from any eye diseases by when subjects complained any kind of discomfort. On the first and the last days of lens wearing, subjective discomfort, blinking rate, lens centration on corneal surface and visible light transmittance of lens were recorded at every case and compared. Results: The circle lens wearers complained subjective discomfort and quit the lens wearing when they wore the circle lens longer than 10 hours even though there were some difference according to the lens materials of daily disposable circle lens. However, around 20% of dry eyes could wear the circle lens made of non-ionic materials longer than 40 hours. Dry eyes showed most sensitive feeling of subjective discomfort against the circle lens made of etafilcon A among three different lens materials. On the last day of lens wearing, the representative subjective discomforts were irritation, stiffness, dryness and tiredness. When the subjects wore circle lens more than the recommended time, blinking rate was significantly increased about 20~30% regardless of lens materials when it compared with the values right after lens wearing. On the last day of lens wearing, the vertical direction of lens centration was shifted to pupil center however, its distribution in horizontal direction was wide compared with the distribution right after lens wearing. Especially, the centration of etafilcon A lens was unstable. Furthermore, the visible light transmittance of 3 different circle lenses in dry eyes has significantly been reduced around 15% averaged. Conclusions: From these results, it was known that the increase of dryness and stiffness caused by overusage of daily disposable circle lens induced excess irritation and decreased visible light transmittance and caused significant more blinking, which provoked lens decentration. It was also revealed that dry eyes showed sensitive reaction subjectively and objectively against the overusage of circle lens made of high water content/ionic lens material even there were some difference of the degree depending on the individual and the lens material. Thus, this research can be suggested as the basic reference for the education about some unexpected problems and the side effect caused by the wearing of circle lens in dry eyes.

• Journal of Korean Ophthalmic Optics Society
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• v.15 no.4
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• pp.329-337
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• 2010

Purpose: The surfaces and compositions of rigid gas permeable (RGP) contact lenses were analyzed with the consistent methods, and the basic informations for the composition design of lens materials were suggested. Methods: The bulk structures were analyzed by using Fourier infrared spectroscopy (FTIR), the compositions of surface components were observed by using x-ray photoelectron spectroscopy (XPS), the surface morphology and roughness were observed using atomic force microscopy (AFM), and the wettabilities were estimated by the surface wetting angles. The relations and trends of those results were analyzed. Results: The high oxygen permeability RGP lenses showed the trend that the fluorine decreases and the silicon increases. As the silicon and fluorine contents increased, the carbon and oxygen contents of RGP lens materials decreased at a constant ratio. The decreasing ratio of the carbon contents was three times larger than the decreasing ratio of oxygen contents. The composition of the surface treated lens was far from these tendency line. When the silicon contents increased, the rough surface was formed with the cohered particles. When the fluorine contents increased, the rough surface was formed with the deep flaws. The surface roughness increased and then wettabilities decreased as the silicon and fluorine contents increased. For the surface roughness changes, the increasing ratio of the silicon contents was two times larger than the increasing ratio of fluorine contents. The surface of RGP lens materials appeared the hydrophobic character of which the wettabilities decreased when the roughnesses increased. Conclusions: The surfaces and compositions of RGP contact lenses were measured by the same methods. Those results and relationships were compared and analysed. It is considered that these research results will be applied with the basic data for the composition design of lens materials.

• Journal of Korean Clinical Health Science
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• v.3 no.3
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• pp.378-389
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• 2015

Purpose. The actual status of wearing toric soft contact lenses was investigated to learn why it is not used although it is required. Materials and Methods. This study has studied 64 contact lens wearing the local college students, Gyeongsangnam-do who are 20.17(${\pm}0.70$)years old, by measuring their refractive power and over-refractive power with auto refractometer(HRK-8000A, Huvitz, Korea). In addition to that, a survey was done to figure out why they do not wear toric soft contact lenses, the purpose of using toric soft contact lenses, whether they have astigmatism or any knowledge about it, the kinds of contact lens, whether they are willing to buy corrective lenses, and how they are satisfied after purchasing them. Results. 17 students (21.9%) said they experienced light-spread; 9 students (14.1%)said that they have dizziness when they wear contact lens all day long. In the survey to see whether they had astigmatism or not, 37 students (57.8%) said they had it. For the reason they do not wear toric soft contact lenses, 33 students (51.6%) said that "they were prescribed regardless of astigmatism in the optometrist." To the question asking if they are willing to buy toric soft contact lenses according to the existence of astigmatism, 51 students (79.6%) answered they are. 31 students (48.4%) said they heard a description about astigmatism at the time of purchase for contact lens. Conclusion. As the ways for any people who need to correct astigmatism to wear corrective lens, enough education about astigmatism and consistent follow-up management are needed, where the role of optometrist is considered important.

• Journal of Korean Ophthalmic Optics Society
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• v.5 no.2
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• pp.11-14
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• 2000

The soft contact lens was very simple technique in handling, good sensation in fitting, good effect of a beauty, and good attachment state on the cornea in physical movement. So that, the subjects have used the correct of visual acuity. If the contact lens handling have not skill, they have acquired the side effect on eye. To analysis of a study of ultrastructure on soft contact lens surface of incubated P. aeruginosa. We have observed the soft contact lens surface by SEM. We have founded the good technical method. On the method of sample process of manufacture, the best observation of samlpe tissue was $OsO_4$ postfixation and tannic acid treatment. In this case, P. aeruginosa was a rod shape and one cilia in ultrastructure and the identification was very good. But, On the process of manufacture have not used the $OsO_4$ and tannic acid treatment, this tissue sample appeared the foreign body materials and artifacts, and the identification of the P. aeruginosa was very difficult.

• Journal of Korean Ophthalmic Optics Society
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• v.10 no.2
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• pp.91-97
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• 2005

We investigated the question whether protein removing activities of enzyme cleaner - protein remover for soft contact lens - are associated with the material of soft contact lens as well as action time, temperature and pH of enzyme solution. We used a subtilisin cleaner as protein remover and estimated the protein amount remained on soft contact lens after using the subtilisin cleaner under the different conditions. The remained protein in soft contact lens was greatly decreased until treatment for 60min, but no significant differences were found from 60min to 24hr. The cleaning effect of the enzymatic treatment in the range of $15{\sim}30^{\circ}C$ was constant. however, there was a significant decline of the protein removing effect at $10^{\circ}C$ and less. The pH of the solution was also important for the efficacy of the enzymatic treatment. The activity of the enzyme cleaner was highest in pH 8.0 and significantly decreased a pH below 7. The pH dependence was found to be related to the conformational change of subtilisin. Furthermore, significant differences in the protein deposit removing efficacy of the subtilisin cleaner were found among the soft contact lens materials.

• Journal of Biomedical Engineering Research
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• v.37 no.5
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• pp.178-185
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• 2016

Tear is a promising biological fluid for non-invasive health monitoring. It has been studied in the past to be a possible candidate for the diagnosis of certain systemic diseases, such as breast cancer, multiple sclerosis, prostate cancer, and diabetes. However, currently existing methods for collecting and extracting tear from the human eye causes inconsistencies in the biomolecule concentrations of the tear sample due to the irritating nature of the process. In response, we designed and fabricated a microfluidic system embedded soft contact-lens for the purpose of tear sampling. The lens was then tested with artificial tear for its tear sampling capability, and found to be able to find concentration equilibrium within 50 minutes. Additionally, simulation was carried out to further optimize the design so that tear sampling rate matched the natural tear turn-over rate of 1 microliter per minute.