• Journal of Korean Ophthalmic Optics Society
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• v.15 no.2
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• pp.137-144
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• 2010

Purpose: This study was to evaluate the clinical performance of 1-Day disposable toric soft contact lenses (TSCL) and to compare the visual performance with glasses and TSCL. Methods: In a two-week investigation of 'prism ballast' designed TSCL, occular refractions in 15 (30 eyes) healthy subjects were within the range of -2.75 D TO -8.00 D spherical power and -0.75 DC to -2.25 DC cylinderical power (with-the-rule). Subjects were assessed the clinical performance (orientation, centration, movement, tightness, rotation recovery, symptoms) of TSCL and compared binocular vision and contrast sensitivity with corrected glasses and TSCL at initial and two-week follow-up visits. Results: The prism-ballast design TSCL achieved better orientation, rotation recovery and symptoms over 2 week period. There was no statistically significant difference between spectacles and TSCL with respect to measuring binocular vision and contrast sensitivity. Conclusions: The clinical performance was good with prism-ballast design toric soft contact lenses. Evaluation of binocular vision and contrast sensitivity did not show the differences between spectacles and TSCL correction. This study suggests that TSCL wearers can be achieved similar visual performance for spectacles wearers.

• Journal of Korean Ophthalmic Optics Society
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• v.6 no.1
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• pp.13-29
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• 2001

A mathematical model was proposed to analyze the vibration of diaphragm, such as the contact lenses fitted on the eyes, being subjected to the external sinusoidal pressure. The model incorporates the differential equations and their numerical solution program, based on the wave equations. Turbo-C and graphic software, formulated to describe the dependence of the various parameters involved in the vibration. The model predicts the radial distribution of amplitude, frequency dependence of both average displacement amplitude and the power of diaphragm whose edge is being either simply supported or rigidly clamped in vibration. The effect of variables such as thickness, radius, damping coefficients on the vibration characteristics was illustrated by the computer simulation of the derived program. As the frequency of driving pressure increases above the certain value determined by the boundary conditions and parameters the wave shape or pattern changes from simple arc to belly or loops having double antinode. It seems that the effect of outer antinode progressively increases as the frequency increases. If this kind of phenomena occurs to the contact lens on the cornea in vivo, it may cause an abnormal correction power in the lenses or pull off the eye due the increased rise of outer part of the lens.

• Journal of Korean Ophthalmic Optics Society
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• v.9 no.2
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• pp.371-380
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• 2004

The history of the glasses can say that we began with the development of the typography. Glasses were made for the first time from the skin which they tied. We came to make the rim as the horn tree afterwards or bone. And the snail glasses make the lens as the modification or glass and to put to connect the two to large snail was developed. The rim after he brought lots of style change. The development of the Bridge and eyewear form of the Temple of an entry today began to come out. The development of and various design and material. We reached practical style. development of design concentration new fashion trend lead can make it eyewear company and designer's. A rim of various style through historical development course because we have a present time's rim analysis. We try to try to investigate a method element of the glass design with a final cause form of the design in the viewpoint of the facility.

• Journal of Korean Ophthalmic Optics Society
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• v.1 no.1
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• pp.23-28
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• 1996

Hydrogenated amorphous carbon films were fabricated by low frequency(60Hz) Plasma enhanced Chemical vapor deposition(LF-PECVD) at room temperature. The LF_PECVD has a couple of advantages as follows: cheap, and the employment of low power density makes the damage of samples small. The a-C:H films deposited in this work were highly transparent(99%), highly resistance(109-1011${\Omega}$-cm), and very uniform. The samples were deposited by the decomposition of CH4 and H2 mixing gas in the pressure rate range of 1% to 30%. The deposition rates, optical gap, and hydrogen contents are increased with CH4 contents.

• Journal of Korean Ophthalmic Optics Society
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• v.15 no.3
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• pp.241-245
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• 2010

Purpose: In this work we suggested a grating chart of vision test which could be used to measure the sense of distance and motion of object. Methods: A couple of gratings with periodic structure were fabricated. Through a lens the grating images showing geometrical shapes were projected on a vision test chart in order to form a new grating chart of vision test. In rotating and translating the gratings the examinee perceived the variation of position of gratings by the variation of the sense of distance and motion. Results: The results of the sense of distance and motion measured in rotating and translating the gratings showed the average errors of ~2.98% and ~1.73% at $\theta=15^{\circ}$ respectively compared to calculated values. Conclusions: The grating chart of vision test suggested in this work can be used as a new test chart that lets an examinee perceive a sense of distance and motion of object.

• Journal of Korean Ophthalmic Optics Society
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• v.13 no.1
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• pp.37-42
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• 2008

Purpose: This study is to prepare tintable hard coatings for plastic lenses and to evaluate spectroscopic and surface characteristic for these coatings. Methods: These coatings had been prepared by the sol-gel method using TEOS, MTMS and GPTS. Scanning electron microscopy (SEM), Raman spectroscopy, infrared (IR) spectroscopy and UV/VIS spectroscopy have been used to investigate the optical and structural characteristics of the coatings. Results: Tint ability of this coating was about 2 times higher than general hard coatings. The lenses applied by tintable hard coatings showed excellent adhesion, abrasion resistance, hot water resistance, and chemical resistance. Pencil hardness was 5H and the surface of coatings was smooth and free of cracks. Conclusions: This hard coating system for plastic lenses offered a hard and stable surface that could be tinted.

• Journal of the Korean Chemical Society
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• v.54 no.6
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• pp.761-765
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• 2010

Poly (N,N-dimethylacrylamide) is very useful in various fields due to its remarkable properties, such as water solubility and biocompatibility. This study used N,N-dimethylacrylamide with the cross-linker EGDMA (ethylene glycol dimethacrylate), HEMA (2-hydroxyethyl methacrylate), MMA (methyl methacrylate), NVP (N-vinyl-2-pyrrolidone) and the initiator AIBN (azobisisobutyronitrile) for copolymerization. Measurement of the physical properties of the copolymerized polymer showed that the water content was 36 - 42%, refractive index was 1.433 - 1.426 and visible ray transmittance 90 - 91% while the oxygen permeability showed a distribution between 13.1 and $21.29{\times}10^{-11}(cm^2/sec)$ ($mlO_2/mL{\times}mmHg$). The measurement showed that the increased amount of oxygen permeability of the copolymer measured using the polarographic method range between 11.0% and 80.5%. Based on the results of this study, the produced copolymer is suitable for use as a material to high oxygen permeability hydrogel lenses.

• Journal of Korean Ophthalmic Optics Society
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• v.19 no.4
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• pp.429-434
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• 2014

Purpose: To analyze thermal effect on mechanical properties of domestic commercial polymer-based eyewear frames. Methods: In this study, materials of cellulose acetate, polyamide, epoxy, and polyetherimide were exposed to high or low temperature and were mounted on universal test machine (TO-100-IC) for tensile strength test. Elastic behavior, Young's modulus, maximum displacement, and fatigue were tested with various temperature ($-25^{\circ}C$, $25^{\circ}C$, $60^{\circ}C$). Results: As a result, at room temperature, displacements of materials were changed with increasing impact load. At low temperature ($-25^{\circ}C$), maximum displacements of all specimens were decreased but young's modulus were increased. However, at high temperature, maximum displacements of all specimens were increased but young's modulus were decreased. Conclusions: Degree of displacements due to fatigue behavior was increased following direction of PEI, epoxy, polyamide, acetate. We concluded that commercial polymers used in eyewear frames physical properties were changed differently to exposed temperature.

• Journal of Korean Ophthalmic Optics Society
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• v.16 no.3
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• pp.293-297
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• 2011

Purpose: This study was to know the correlation among refractive error and the dimensions of ocular components on older adults. Methods: The subjects were 95 older age who had no eye diseases. The refractive error, corneal radius, corneal diopter, axial length, anterior chamber depth and lens thickness were measured and analysed. Results: The axial length(AL)/corneal radius(CR) ratio was positively correlated with the corneal diopter, axial length, the anterior chamber depth. Then it was negatively correlated with corneal radius. It was shown that the highest correlation was between the corneal diopter and axial length (r = -0.545, p = 0.000). The spherical equivalent of the refractive error was negatively correlated with the AL/CR ratio. Conclusions: It was shown that the AL/CR ratio was a very important indicator for diagnosing the refractive error of the old age.

• Journal of Korean Ophthalmic Optics Society
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• v.16 no.3
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• pp.283-291
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• 2011

Purpose: To find an empirical fitting curve to represent the relationship between the luminous transmittance and tinted time in tinted lenses using exponential decay curves. Methods: Total ninety tinted lenses were prepared with CR-39 lenses and six different colored dyes. Single, double and triple exponential decay curves were used as trial curves in order to find the empirical fitting curve. Result: The results showed that the best empirical fitting curve was triple exponential decay curves. Conclusions: We propose triple exponential decay curves as proper empirical fitting curves to represent the tinted-time dependence of the luminous transmittance in tinted lenses.