• Journal of Korean Ophthalmic Optics Society
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• 제20권4호
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• pp.425-435
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• 2015

Purpose: This study analyzed the names of optical shops currently used in Korea and is to investigate the optical shop names that customers prefer. Methods: We used the 351 names of optical shop all over the country as a sample, and surveyed 296 people aged between 20s~30s in Seoul and Gyeonggi provinces to collect the data. Results: The most used names are currently English names (54.4%) and names of with 2 syllables (30.5%) and 3 syllables (32.5%). For more than 4 syllables, the names included Eye (26.0%) and Glasses (24.3%) are being used a lot. For the name awareness, Korean names (63.0%) was the highest and followed by 1syllable (34.5%) and 5 syllables (20.9%). Conclusions: For the improvement of optical shop awareness, Korean name with 1 to 3 syllables and words related glasses are recommended.

• The Transactions of the Korean Institute of Electrical Engineers C
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• 제48권1호
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• pp.12-17
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• 1999

$MgIn_2Se_4 and MgIn_2Se_4 : Ni^{2+}$ single crystals were grown in the rhombohedral structure by the chemical transport reaction (C.T.R.) method using iodine as a transport agent. The optical absorption measured near the fundamental band edge showed that the optical energy band structure of these compounds had a direct band gap. The fundamental absorption band edge of these single crystals shift to a shorter wavelength region by decreasing temperature and the temperature dependence of the optical energy gaps in these compounds satisfy Varshni equation. The impurity optical absorption peaks due to nickel are observed in $MgIn_2Se_4 and MgIn_2Se_4 : Ni^{2+}$ single crystal. These impurity optical absorption peaks can be attributed to the electronic transitions between the split energy levels of $Ni_{2+}$ ions located at $T_d$ symmetry site of $MgIn_2Se_4$ host lattice. In the hotoluminescence spectrum of the single crystal at 10 K, a blue emission with a peak at 687nm and a green emission with a peak at 815nm for the $MgIn_2Se_4$ single crystal were observed.

• Journal of Korean Ophthalmic Optics Society
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• 제19권1호
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• pp.1-8
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• 2014

Purpose: To observe changes of coatings and lens materials with varying temperature to understand effect of temperature on plastic lens. Methods: In this study, three lenses of different refractive indices (2 of thiourethane oriented lenses, an allyl diglycol carbonate oriented lens) were exposed to high temperature (50, 80, and 100 degree) for 5 hours and changes of individual coating (anti-refractive coating, hard coating, and water repellent coating) were measured. Results: As a result, high-refractive index lenses did not exhibit significant variation of hardness. However, hardness of mid-refractive index lens were decreased when exposed to high temperature and destructions of hard coating layer was inferred. Surface contact angles of lens were decreased with increasing temperature and water repellent coating layer were damaged at higher than 80 degree. Conclusions: Multi including water repellent coatings on all three lenses with different refractive indices were damaged when exposed to at or higher than 80 degree. The degree of changes in mechanical and physical properties were depended on polymer material type.

• Journal of the Korea Academia-Industrial cooperation Society
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• 제10권11호
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• pp.3427-3433
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• 2009

This paper attempted to suggest the standards of light transmittance based on the analysis of the changes in contrast sensitivity of photopic condition according to the light transmittance of tinted lenses. The subjects of the experiment were 24 male and 13 female adults with normal ocular functions. They were asked to wear four tinted lenses (gray, brown, red, and green) in turn. The light transmittance of the lenses were 80~90%, 60~80%, 43~60%, and 30~43%, respectively. Contrast sensitivities were measured by using F.A.C.T. chart. The results showed that contrast sensitivities were decreased in proportion to the decrease of the light transmittance, and visual sensitivity of brown lenses were the highest and that of red lenses were the lowest. The results of the experiments suggested that the light transmittance should be over 38% for brown, gray and green lenses, and over 52% for red lenses. Accordingly the appropriate light transmittance should be considered when tinted lenses are selected for the purpose of eye protection in everyday life.

• Journal of Korean Ophthalmic Optics Society
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• 제11권1호
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• pp.71-75
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• 2006

The aim of this study was to analyze the surface ultrastructure of RGP contact lenses post-use The RGP contact lenses, to investigate, were selected after one month, six months and one year of wear by the subjects. The anterior and posterior surfaces of these RGP contact lenses were inspected by a scanning electron microscope. The results were the following: 1. After one month of RGP contact lens use the anterior and posterior surfaces appeared clean and clear as originally. 2. After six months the anterior surface had several scars, dips, cracks and scratches. Upon the posterior surface appeared several foreign bodies and microorganisms. 3. After one year there was large scale damage and many foreign bodies were observed. Therefore, extended use of RGP contact lenses has shown increasing physical damage and extensive foreign body accumulation upon the ultrastructure of the lens surface.

• Journal of Korean Ophthalmic Optics Society
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• 제11권2호
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• pp.85-89
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• 2006

To research of the improved mechanical properties of materials for spectacle lens cutting, SiC and TiC were used as the main powder. Also, $Al_2O_3$ and $Y_2O_3$ was included as a sintering additive. The weight ratio of the alumina($Al_2O_3$) to yttria($Y_2O_3$) was set to 1:1. The materials for spectacle lens cutting were fabricated by hot-pressing at $1810^{\circ}C$ for 1h and subsequently annealed at $1860^{\circ}C$ for 3, 6 and 12h to initiated grain growth. The longer annealing time is, the bigger the grain size is. The microstructures were observed by scanning electron microscopy (SEM). The SEM images were quantitatively analyzed by image analysis (Image-Pro Plus, Media Cybernetics, Maryland, U.S.A.). Crack deflection by elongated SiC grains was most frequently observed as the dominant toughening mechanism. Crack deflection was generally observed for elongated SiC grains with aspect ratio(AR) > 2.5 and grain thickness < $2.3{\mu}m$. Crack bridging was also observed as one of the operating toughness mechanism.

• Journal of Korean Ophthalmic Optics Society
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• 제20권2호
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• pp.229-235
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• 2015

Purpose: This study was undertaken to study on visual function before and after prescription of vertical prism. Methods: 80 subjects (10-30ages) who had been precribed vertical prism and 1 year after they were represcribed vertical prism. Results: Phoria (p=0.000), supra vergence (p=0.000), NPC (p=0.003), NPA (right eye) (p=0.005), NPA(left eye) (p=0.000) showed a significant change. Conclusion: Vertical prism prescription was reduced during revisit. Supra vergence, NPC, NPA(right eye), NPA(left eye) showed a significant change. Binocular Accommodative lag was not associated with vertical prism prescription and binocular vision findings.

• Journal of Korean Ophthalmic Optics Society
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• 제17권4호
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• pp.321-334
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• 2012

Purpose: In this study, the distribution and differences in refractive powers on trial case lenses were investigated. Methods: We measured refractive powers at optical center and periphery using 4 trial case lens sets. According to international standards, the distribution and uniformity in refractive powers were investigated. Results: The lens shapes were different in different kinds of trial case lenses and some of lenses were out of tolerance according international standards. In some cases, the power differences were found between front and back side as well as between optical center and peripheral regions and also the cylindrical power on spherical lens and spherical power on the cylindrical lens were measured. Conclusions: Trial case lens are used to assess the refractive error, therefore, more precise control of the manufacturing process for trial case lenses and more thorough quality control will be required to offer an accurate vision test. More careful attention in using trial case lens is also required.

• Journal of Korean Ophthalmic Optics Society
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• 제17권4호
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• pp.469-476
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• 2012

Purpose: The purpose of this study is to investigate the changes of asphericity according to diameter and direction of the cornea. Methods: The changes of asphericity according to diameter and direction of cornea is measured by using Pentacam(Oculus Co., Germany), as targeting 57 adults (average $27.0{\pm}4.8$, 20 men, 37 women) without any ophthalmic diseases, which may be effective in eyesight, and refractive surgery. Results: As diameter increases in every direction based on the corneal vertex, asphericity has attentively increased (p<0.05), and the size of asphericity in each direction from every measured diameter showed as superior > nasal > inferior > temporal. In group comparison by nearsightness and astigmatism level, asphericity measured high when nearsightness and astigmatism levels were higher, and this appears to be statistically attentive.(p<0.05). Conclusions: Asphericity of cornea significantly increased according to increase of diameter of cornea, and as measured figure or increased quantity appeared differently in all directions based on corneal vertex, so it helps to understand shape of cornea, and considered that is the part to be considered during manufacturing and fitting of RGP lenses.

• Journal of Korean Ophthalmic Optics Society
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• 제19권4호
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• pp.539-550
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• 2014

Purpose: This research was designed to figure out if there are changes based on types of vergence fixation disparity curve after optical correction and vision training to for people with steep slope of forced vergence fixation disparity curve and symptoms. Methods: For 30 subjects out of 91 subjects, who have steep slopes of fixation disparity curve examined with Wesson Fixation Disparity Card and symptoms about steep slope of fixation disparity curve, proper vision training was offered for 5 weeks. Results: After Vision training for 30 people with the symptoms of type I, II, III, IV for 5 weeks, slope of fixation disparity curve was significantly changed (p=0.013), and the results of binocular vision test and subjective symptoms were also significantly improved. Conclusions: Vision training can not only affect the change of fixation disparity curve, but also relieve the symptoms. Fixation disparity curve has lots of visual function information of the subject and can be suggested as a guideline for prescribing.