• Journal of Korean Ophthalmic Optics Society
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• v.15 no.3
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• pp.281-286
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• 2010

Purpose: This research provided basic data for refraction by comparing the corrected diopter of trial lens and phoropter. Methods: We compared the corrected diopter of trial lens and phoropter, and analyzed statistical significance and relations of the spherical lens corrected diopter and cylindrical lens corrected diopter according to the types (trial lens and phoropter) of subjective refractive instruments. Also we analyzed statistical significance and relations between cylindrical lens corrected diopter at the astigmatism and the types (trial lens and phoropter) of subjective refractory instruments. Results: When we measured the corrected diopter of simple myopia, the mean value for corrected diopter was S-2.74D using the trial lens and S-2.65D using the phoropter. So the corrected diopter was 0.09D smaller when measured by phoropter. The degree of astigmatism was measured C-0.81D using the trial lens and C-0.77D using the phoropter which showed that the measured value was 0.04D smaller using the phoropter. On correlation analysis between the refractive instruments (trial lens and phoropter) and the corrected diopter, there was significant (p<0.01) strong correlation between refractory machine and corrected spherical diopter (r=0.996) and the correlation between refractory machine and corrected cylindrical diopter was r=0.986 and was also significant (p<0.01). Conclusions: The use of phoropter than trial lens was more desirable when performing refraction on high myopia (simple refractive error, high astigmatism), and when using trial lens, you should consider the vertex distance and the gap between overlapped lenses before prescription.

• Journal of Korean Ophthalmic Optics Society
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• v.20 no.4
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• pp.501-509
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• 2015

Purpose: To evaluate the reliability of refractive power by comparing the marked refractive power in an automatic phoropter and actually measured spherical/cylindrical refractive power. Methods: Actual refractive power of minus spherical lens and cylindrical lens in an automatic phoropter was measured by a manual lensmeter and compared with the accuracy of marked refractive power. Furthermore, combined refractive power and spherical equivalent refractive power of two overlapped lenses were compared and evaluated with the refractive power of trial lens. Results: An error of 0.125 D and more against the marked degree was observed in 70.6% of spherical refractive power of spherical lens which is built in phoropter, and the higher error was shown with increasing refractive power. Single cylindrical refractive power of cylindrical lens is almost equivalent to the marked degree. Combined spherical refractive power was equivalent to spherical refractive power of single lens when spherical lens and cylindrical lens were overlapped in a phoropter. Thus, there was no change in spherical refractive power by lens overlapping. However, there was a great difference, which suggest the effect induced by overlapping between cylindrical refractive power and the marked degree when spherical lens and cylindrical lens were overlapped. Spherical equivalent refractive power measured by using a phoropter was lower than that estimated by trial glasses frame and marked degree. The difference was bigger with higher refractive power. Conclusions: When assessment of visual acuity is made by using an automatic phoropter for high myopes or myopic astigmatism, some difference against the marked degree may be produced and they may be overcorrected which suggests that improvement is required.

• Journal of the Korean Society for Precision Engineering
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• v.28 no.3
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• pp.370-376
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• 2011

Recently, the application range of plastic gears is widely expanding by the development of engineering plastics with good mechanical properties. Plastic gears have excellent performances such as light weight, water resistance and vibration absorbing ability for metallic gears. In this study, the optimization of injection molding process was done for the large disk type plastic gears of auto phoropter. Design Of Experiment (Taguchi method) was adopted to find a tendency of molding conditions that influence the flatness of disk type gear. Four main factors for molding conditions were selected based on injection temperature, filling time, packing pressure and mold temperature. Also, Filling, packing and cooling analyses were carried out to evaluate Z directional deflection of large disk type gear by using the simulation software (Moldflow) based on the DOE. From the results, it was found that the injection temperature and packing pressure are the most sensitive parameters for the Z directional deflection of large disk type gears.

• Journal of Korean Ophthalmic Optics Society
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• v.9 no.1
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• pp.1-9
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• 2004

In this study, we presented a research about the development of the phoropter simulation program for education using the 3-D virtual reality in order to study the ophthalmic optics rather efficiently. Especially, by putting the facility such as the refractive error analysis of the eyeball in the cyber tutor inside, we have made the learner to learn and confirm the present situation of refractive correction through refractive power of principal meridians. By organizing the system which induces the active involvement of the learner and showing the result of the execution to the learner intuitively, the implementation of the more efficient education-environment can be possible. Consequently, it is expected that this program will be greatly helpful for the optician training as well as the ophthalmic optics education. As a next phase of study, we will develope the development technique of this simulator more and extend the cyber tutor contents more and make the web service version of this program to be provided through the internet network in order to inspire the learning desire of the learner more and more.

• Journal of Korean Ophthalmic Optics Society
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• v.19 no.2
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• pp.231-237
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• 2014

Purpose: This study is research of the conditions which causes difference between the refractive power of the measurement of autorefractometer and the prescription using phoropter. Methods: Autorefractometer (SR-7000) and phoroptor (AV-9000) were used to measure 60 eyes of 30 participants who had no eye diseases and wore the corrective lens due to Ametropia. To prevent the dependence of the prescription value of the refractive power on the testers, two testers measured the refractive power of the eyes of the participants at the same measuring conditions. Results: Statistically, the prescribed values of the refractive power by two testers were not significantly different. Most of the prescribed values of the refractive power were smaller than the refractive power by autorefractometer In case of myopic eyes, the difference between refractive powers by the measurement of autorefractometer and the prescription using phoropter showed the trend of increase as the spherical refractive power became larger. The result was analyzed by the range of the different cylindrical refractive power for the myopic astigmatic eyes. In this case, the difference between refractive powers showed the trend of decrease as the cylindrical refractive power became larger. Conclusions: No difference between the prescribed value by two testers was observed. In case of myopic or myopic astigmatic eyes, the difference between refractive powers by autorefractometer and the prescription were measured to be approximately proportional to the refractive powers of ametropic eyes. As the this difference become larger for the participant who needs the lens of larger refractive power, additional caution is needed in the prescription of the refractive power of the corrective lens.

• Journal of Korean Ophthalmic Optics Society
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• v.19 no.1
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• pp.105-109
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• 2014

Purpose: To compare the change of visual acuity and NIBUT after watching smart-phone in 1 hour under low intensity of illumination. Methods: 50 subjects (male 22, female 28) aged 20's years old ($20.7{\pm}2.4$ years) who do not have eye disease and have a good eye condition were participated for this study. Objective refraction, corrected distance visual acuity and NIBUT were measured before and after watching smart-phone (Galaxy 2, Samsung, KOREA) under low intensity of illumination (0 lx.) Objective refraction was carried out using auto-chart project (CP-1000, Dongyang, Korea), phoropter (VT-20, Dongyang, Korea) and auto refractor-keratometer (MRK-3100, Huvitz, Korea). Results: Refractive error was changed from $-3.20{\pm}2.00$ D to $-3.38{\pm}2.00$ D (p=0.006) and corrected distance visual acuity was changed from $0.93{\pm}0.08$ to $0.91{\pm}0.10$ (p=0.000) and NIBUT was changed from $10.48{\pm}7.00$ seconds to $10.29{\pm}6.47$ seconds (p=0.761) before and after watching smart-phone under low intensity of illumination. Conclusions: Continuous watching smart-phone under low intensity of illumination lead to temporal change of distance visual acuity and suitable rest may reduce the influence of distance visual acuity and tear safety.

• The Journal of Korea Robotics Society
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• v.5 no.4
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• pp.359-366
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• 2010

This study proposes the design method for the robot rotation arm which the end effector that is connected in end of the arm keeps parallel motion even though the robot arm rotates. So far, most robot arm rotates together the end effector when the arm rotates. For this, this study proposes the mechanism that the arm is linked to each 4 parallel link so that rotation is possible by 4 pins, and the rotation arm connects 2 joints of diagonal line direction to a link in each 4 joint for rotation, and designs so that can change length of the link. For verification of design, this study targeted that develop the rotation arm for medical examination that use in ophthalmology. It is important that a medical robot offers comport to patient and design compactly so that medical examination and treatment space may can be defined enough. It is designed so that all drive elements may be positioned on interior of the arm and optimization of design for main parts was carried out in this study for this. The robot arm which is developed in this study manufactured to use by medical phoropter arm, and got good result by an experiment. The robot rotation arm which is proposed in this study is judged to contribute very effectively in case use of a medical robot arm for medical examination and treatment, also the robot arm which the end effector that is connected in the end of the arm needs to keep parallel motion. And, the robot arm which is developed in this study made an application as license.

• Journal of Korean Ophthalmic Optics Society
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• v.10 no.4
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• pp.375-380
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• 2005

To assess convergence and accommodation at a short distance, 92 selected subjects without any ocular diseases by apperatuses of visual chart(Shinnippon CT30) and phoropter(Shinnippon VT 10) at a short distance(40 cm) were tested upon MEM retinoscopy(Welch Allyn, USA). BELL retinoscopy(Welch Allyn, USA), binocular accommodative facility (${\pm}2.00$ D flipper. Bernell Co., USA), vergence facility(prism flipper, Bernell Co., USA). There were such test results as MEM retinoscopy(R/L)($+1.05{\pm}0.87/1.02{\pm}0.80$ D). BELL retinoscopy ($17.89{\pm}12.12/17.94{\pm}11.72cm$), binocular accommodative facility (R/G)($7.69{\pm}6.48cpm$). binocular accommodative facility(polaroid)($11.76{\pm}5.22cpm$), monocular accommodative facility(R/L) ($13.9{\pm}6.27/13.8{\pm}5.96cpm$), vergence facility($13.5{\pm}6.40cpm$).

• Journal of Korean Ophthalmic Optics Society
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• v.10 no.4
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• pp.381-389
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• 2005

To Analysis of Correlation of Visual Function Findings, by assessing convergence and accommodation, 92 selected objects without any ocular diseases by apperatuses of visual chart(Shinnippon CT30) and phoropter(Shinnippon VT10) at a shan distance(40 cm) were tested upon MEM retinoscopy(Welch Allyn, USA), BELL retinoscopy(Welch Allyn, USA), binocular accommodative facility (${\pm}2.00$ D nipper, Bernell Co., USA), vergence facility(prism nipper, Bernell Co., USA). The results showed as follows. MEM retinoscopy(accommodative lag) showed the same result of a right eye and left eye. Bell retinoscopy(accommodative lag) showed higher correlations between right and left eye than MEM. The lower accommodative lag meant the higher accommodative facility. The binocular accommodative facility(polaroid) was higher than binocular accommodative facility(red-green). Correlations of accommodative facility between right and left eye were higher, and as the higher monocular accommodative facility also meant the higher binocular accommodative facility, monocular and binocular accommodative facilities were relative to vergence facility, These findings can be used as a clinical guide by curing patients' visual function.

• Journal of Korean Ophthalmic Optics Society
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• v.10 no.2
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• pp.103-110
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• 2005

Binocular vision had a short history in Korea. As there were many near works in these days, the needs about comparative study have been increased. There was related to both refractive error and binocular anomalies, but it is difficult to applying for binocular vision expected findings in itself due to the fact that Korean differ from foreigner. Objects were 100 adults in 18-36 years old ages, The test was Von Gaefe method and used aparatus was phoropter(Shinnippon VT10)and visual chart(Shinnippon CT30). According to interview results was that symptom in near works were headaches 28.0%, blinking 27.3%, red eye 25.1%, eyepain 15.6%, watering 15.3%, itch 12.2%, photophobia 8.5% and eye strain 7.4%. A people who have above ${\pm}0.50$ D refractive error in total objectives (100-male 45/female 55) were classified into ametropia. There was a results such as emmetropia (12.0%), ametropia(88.0%), exophoria(32.0%), esophoria(12.0%). Far negative relative convergence were that in case of high 43.0%, in case of low 7.0%. Far positive relative convergence were that in case of high 15.0%, in case of low 38.0%. Near phoria was exophoria(32.0%), esophoria(12.0%). Near negative relative convergence were that in case of high 23.0%, in case of low 38.0%. Far positive relative convergence were that in case of high 29.0%, in case of low 23.0%. Near negative relative accommodation were that in case of high 10.0%, in case of low 14,0%, Far positive relative convergence were that in case of high 69.0%, in case of low 12.0%. Results were different from expected findings, and especially positive relative accommodation was very high, However, We suggest that the expected findings in Korea for several subjects must study in binocular function.