• The Korean Journal of Vision Science
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• v.20 no.4
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• pp.523-530
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• 2018

Purpose : The purpose of this study was to investigate the difference in the dynamic visual acuity between (DVA) the distance and near and the effect of change of accommodative stimulus on the dynamic visual acuity by the addition of the plus lens. Methods : The study involved 40 male and female adults ($22.84{\pm}2.43$ years old) with over 1.0 of visual acuity and without systemic disease or ocular disease. We compared the distance and near DVA and the change of DVA induced by the addition of the plus lens(+0.50D, +1.00D, +1.50D). Results : The distance DVA and near DVA are $78.86{\pm}19.46deg/sec$ and $76.90{\pm}18.05deg/sec$ respectively. The distance DVA was slightly higher(p=0.04). The higher the distance DVA, the higher the positive correlation with the near DVA and distance DVA, and distance DVA was higher in those who had higher the near DVA(r=0.95, p=0.00, Fig. 4). The near DVA according to the change of accommodative stimulus was $75.95{\pm}18.85deg/sec$ in full correction and the near DVA with +0.50D spherical power was $76.95{\pm}16.45$ but there was no statistically significant differences(p>0.05). However, the near DVA with +1.00D spherical power was $79.02{\pm}13.51deg/sec$ and it was slightly higher. Also, the near DVA with +1.50D spherical power was $84.28{\pm}18.96deg/sec$, there and it was statistically significant difference(p<0.05). Conclusion : There is no difference between distance and near DVA, but near DVA is also excellent if distance DVA is good. The DVA increases as added a plus lens for controlled accommodative stimulation changes.

• The Korean Journal of Vision Science
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• v.20 no.4
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• pp.497-504
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• 2018

Purpose : The purpose of this study was to investigate the temperature changes of the ocular surface before and after cataract surgery using thermography of a thermal imaging camera. Methods : The study included 75 patients (75 eyes) aged from 50 to 79 years who underwent cataract surgery. In the past, those who underwent corneal-related surgery, wearing contact lens, disorder of tear secretion and taking medication for systemic disease were excluded from this study. The temperature changes of the eyeball surface were measured using a thermal imager (Cox CX series, Answer, Korea) following Tear Break Up Time (TBUT) test, Mcmonnies questionnaire and Schirmer's Test in real time, Results : While the temperature of preoperative ocular surface was $35.20{\pm}0.54^{\circ}C$ and that of postoperative temperature was $35.30{\pm}0.53^{\circ}C$, the difference was not significant. The temperature changes in the ocular surface were statistically significant at $-0.12{\pm}0.08{\Delta}$ ($^{\circ}C/sec$) before the surgery and $-0.18{\pm}0.07{\Delta}$ ($^{\circ}C/sec$) after the surgery. In comparison of the age groups, it was shown that the changes in the surface temperature before the surgery were from $-0.19{\pm}0.05{\Delta}$ ($^{\circ}C/sec$) to $-0.14{\pm}0.09{\Delta}$ ($^{\circ}C/sec$) in the 50s group, and from $-0.12{\pm}0.08{\Delta}$ ($^{\circ}C/sec$) to $-0.15{\pm}0.07{\Delta}$ ($^{\circ}C/sec$) in 60s group, and $-0.18{\pm}0.07{\Delta}$ ($^{\circ}C$) to $-0.12{\pm}0.08{\Delta}/sec$) in the 70s group, showing significant changes in the ocular surface temperature at all ages. Conclusion : Following the cataract surgery, all the indicators of dry eye syndrome were decreased, and eye surface temperature changes were significant. The thermography technique of the ocular surface would be expected to be useful for the evaluation of various dry eye syndromes because it is easy to evaluate dry eye syndrome noninvasively and can be quantified.

• The Korean Journal of Vision Science
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• v.20 no.4
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• pp.561-568
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• 2018

Purpose : The size and regular array of the collagen fibers in the corneal stroma have very close correlation with transparency. Simulation was carried out to investigate the change of light transmittance according to the array structure and collagen fiber layer thickness. Methods : The collagen fibers in corneal stroma were arranged in regular hexagonal, hexagonal, square and random shapes with OptiFDTD simulation software, and the light transmittance was analyzed. In square array, the light transmittance according to the density change was confirmed by when the number of collagen fibers in the simulation space was the same and the light transmittance was examined when the number and density of collagen fibers were changed. Results : When the number of collagen fibers is the same, the density becomes smaller and the thickness of the fibrous layer becomes thicker in order of arrangement of square, regular hexagonal, random and hexagonal. As a result of measuring the light transmittance by changing the array structure, the light transmittance measured at the detector at the same position was almost similar regardless of the array structure. In the detectors D0, D1, D2 and D3, the maximum transmittance is shown in square, hexagonal and square, regular hexagonal and regular hexagonal array structure, and the minimum transmittance is hexagonal, random, hexagonal and square, and square array structure. However, the difference between the maximum transmittance and the minimum transmittance was almost the same within 1%. When the number of collagen fibers was the same, the light transmittance of the rectangular array structure decreased with increasing fiber layer thickness. And as the thickness increased, the light transmittance decreased more when the number of collagen fibers decreased. Conclusion : Even though the collagen array structure changed, the light transmittance is almost similar regardless of the arrangement structure. However, as the array structure was changed, the thickness of the collagen fiber layer changed, and as the thickness increased, the light transmittance decreased. In other words, the transparency of the corneal stroma is more closely related to the thickness of the fibrous layer than the array of collagen fibers.

• Journal of Korean Ophthalmic Optics Society
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• v.16 no.4
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• pp.363-373
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• 2011

Purpose: To establish basic data for effective management and quality improvement on clinical practice by investigating the clinical practice satisfaction of ophthalmic optics students and optical shop owners. Methods: A survey was administered for 281 students with experience in clinical practices and 105 optical shop owners regarding satisfaction of ophthalmic optics students and optical shops. And a statistical analysis was performed on the survey results. Results: 92.% (97 shops) of optical shop owners responded that clinical practice was necessary and there was a significant difference (p=0.004) according to gender. 4 weeks was the preferred length of practice period (53.3%) and there was a significant difference according to the size of the optical shops (p=0.000). Clinical practice satisfaction of students was 3.50 ${\pm}$ 0.68 and satisfaction for clinical practice program, clinical practice time and clinical practice shop (3.74 ${\pm}$ 0.80) were the highest and there was a significant difference according to the age of the students (p<0.05). Clinical practice satisfaction for optical shops was 4.08 ${\pm}$ 0.64 which is higher than student satisfaction. Satisfaction for clinical practice program was (4.17 ${\pm}$ 0.54) was the highest. Conclusions: To maximize the effects of clinical practice, a clinical practice program reflecting the satisfaction of students and optical shops is required and further research and attention are required.

• Journal of Korean Ophthalmic Optics Society
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• v.18 no.1
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• pp.67-73
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• 2013

Purpose: Recently, bacterial contamination of equipment and accessories required for vision correction has become a main causal factor in ophthalmic diseases. Thus, We investigated on both the actual condition of bacterial contamination from glasses of vision correction. Methods: Investigation of microorganisms was carried out with a group of 145 glasses wearers, composed of 36 elementary school students, 37 middle school students, 38 high school students, 10 college students, and 32 aged men. Results: Seventeen species of bacteria are detected from glasses of vision correction: B. cereus, B. licheniformis, Bacillus sp., CNS, Enterococcus sp., Escherichia coli, Proteus sp., Pseudomonas sp., Serretia sp., Streptococcus sp., Staphylococcus epidermidis, Staphylococcus aureus, Streptococcus hemolyticus,, Acinetobacter sp., Enterobacter cloacae, GNR, and Pseudomonas aeruginosa. Among 17 species of bacteria, there are some potential causative agents for keratitis, corneal ulcer, Acute dacryocystitis, Orbital cellulitis, Periphlebitis retinae, Marginal blepharitis, and Acute conjunctivitis. Enterobacter cloacae, Pseudomonas aeruginosa and Staphylococcus epidermidis cause keratitis. Pseudomonas sp., and Staphylococcus aureus cause corneal ulcer. Staphylococcus aureus causes acute dacryocystitis, orbital cellulitis, periphlebitis retinae, marginal belpharitis. Streptococcus hemolyticus causes acute conjunctivitis. Conclusions: In summation, it is verified that hazardous, opportunistic and infectious microorganisms exist in glasses for vision correction. Ophthalmic diseases are predicted. Therefore, supplementary research on the development of a cleaning solution to cleanse the infection and of an effective method to remove microorganisms is required.

• Journal of Korean Ophthalmic Optics Society
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• v.10 no.4
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• pp.419-428
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• 2005

The aim of this study was to provide data for the relief of asthenopia during binocular vision by determining the characteristics of ocular function in adults. A total of 260 subjects were between the age of 19-35years. We measured individually the refractive error correction, pupillary distance, optical center distance, phoria, convergence, accommodation and the AC/A as well as the asthenopia during binocular vision using a questionnaire. After analysis of factors affecting asthenopia, we also examined the reductive effect of asthenopia in subjects who had asthenopia using prism. To determine the factors affecting asthenopia during binocular vision, statistic analyses were carried out the multivariate Logistic regression model. The results of this study were as follow. The asthenopia during binocular vision was found 26.9% of subjects. Multivariate logistic regression model was used to determine factors affecting binocular vision of myopia. When the accommodation and convergence were low compared to being high, when subjects had esophoria or there was more exophoria, and when AC/A was lower than the standard, the rate of asthenopia was higher. Therefore the accommodation, convergence and AC/A could be predictive factors for asthenopia. We used prism for subjects who had asthenopia during binocular vision, the results showed that the symptom of asthenopia was eased up to 74.3%.

• Korean Journal of Microbiology
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• v.47 no.2
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• pp.151-157
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• 2011

This study was to examine the quality characteristics and biological activities of the yogurt containing dual fermentation MFCY (Monascus-Fermented Chinese Yam) powder. Six different contents (0, 0.1, 0.3, 0.5, 1.0, and 2.0%, w/v) of MFCY powder were added to raw milk and 5% skim milk followed by fermentation with lactic acid bacteria at $37^{\circ}C$ for 12 h, and then the biological activities of the samples were investigated. Biological activities of the prepared yogurt were evaluated for acid production (pH, titratable acidity), number of viable cells, total polyphenol contents, DPPH radical scavenging activity, reducing power, angiotensin converting enzyme inhibitory effects and GABA contents. In this study, the results show that after fermentation in raw milk and 5% skim milk added with MFCY powder. The yogurt can produced pH, titratable acidity, number of viable cells, total polyphenol contents, DPPH radical scavenging activity and reducing power at 4.12-4.25 (pH), 0.94-0.97% (TA), $7.50{\times}10^9-1.14{\times}10^{10}$ CFU/ml, 161.4-329.9 (TP, mg/L), 54-94% (DPPH), and 1.13-1.53 (R.P), respectively. In addition, the showed ACE inhibitory activity and GABA contents was 67.1-87.7% and 304.6-685.4 (mg/L).

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.9
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• pp.3406-3411
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• 2010

Assessment of the accommodative response is an essential part of the optometric examination. This study measured objectively the accommodation responses those were measured by Autorefractor, MEM retinoscopy and Nott dynamic retinoscopy, and investigate the correlation and difference the results. Twenty-seven college students with normal visual acuity aged 19 to 29 years (mean $22.7{\pm}2.43$ years) participated in this study. Their accommodative responses to accommodative demand of 4D (25cm) were measured with Shin-Nippon NVision-K 5001 Autorefractor, MEM retinoscopy and Nott dynamic retinoscopy. The accommodative responses to accommodative demand of 4D were $3.70{\pm}0.25D$ by Shin-Nippon NVision-K 5001 Autorefractor, $3.58{\pm}0.30D$ by MEM retinoscopy and $3.77{\pm}0.29D$ by Nott dynamic retinoscopy, respectively. There were high correlations among the three techniques (p<0.05). MEM retinoscopy was measured $0.19{\pm}0.13D$ lower than Nott dynamic retinoscopy (p<0.05) and it was measured $0.12{\pm}0.24D$ lower than Shin-Nippon NVision-K 5001 Autorefractor (p<0.05). There was no significant difference between Nott dynamic retinoscopy and Shin-Nippon NVision-K 5001 Autorefractor (p>0.05). MEM retinoscopy showed lesser accommodative responses than Nott dynamic retinoscopy and Shin-Nippon NVision-K 5001 Autorefractor. Author suggest that Nott dynamic retinoscopy may use Shin-Nippon NVision-K 5001 Autorefractor interchangeably to evaluate accommodative responses expect MEM retinoscopy.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.11 no.10
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• pp.3789-3793
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• 2010

To investigate accuracy of graduated scale of schematic retinoscope training eye(schematic eye) and induced effect when measured at off-axis from visual axis. Two skilled retinoscopist measured refractive power using retinoscope in random order. Seven schematic eyes from a single manufacturer were recruited and set to mark +4.00 to -6 diopter(+4, +3, +2, +1, 0, -1, -2, -3, -4, -5, -6). After introducing +2.00 diopter trial lens(50cm working lens), neutral distance was measured at 180 degree to estimate accuracy of scale, and refractive power measured at 0, 5, 10, 15 and 20 degree off-axis to see if any error was induced. According to the results measured by two specialists, in six of seven schematic eye, scale setting varied (p<0.05) and measured refractive power at 5, 10, 15 and 20 degree off-axis from visual axis were $-0.13{\pm}0.06$, $-0.29{\pm}0.06$, $-0.58{\pm}0.11$, and $-0.83{\pm}0.16$ diopter respectively. In some schematic eye, scale graduated on the schematic eye and scale measured by retinoscopy could be different and if retinoscopy is performed off-axis from visual axis, any measuring error can be caused.

• Journal of Korean Ophthalmic Optics Society
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• v.9 no.2
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• pp.361-370
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• 2004

The purpose of this study was to evaluate the outcome and Factors that influence the quantity of Phoria in the low correction and perfect correction. Also the coincidence with the opticenter and the pupillary distance was a principal factor that influence the quantity of Phoria. Thereupon, this study is attributed to promote the perfect Phoria test. The subjects for this study were 120 persons(240 eye) in myopic refractive errors. ISP/WIN program was used for the data analysis. The collected data was analyzed by descriptive statistics and Spearman's correlation coefficient. The results of this study were as follows: 1. The prism pattern was difference between low correction and perfect correction in the Phoria test. The proportion of orthophoria was changed from 10.0% to 12.5%, exophoria was changed from 67.5% to 62.5%, and esophoria was changed from 22.0% to 32.5%, respectively. 2. The average of optical center distance and pupillary distance were 31.70mm and 31.49 mm, respectively. 3. Among the 120 myopic glasses wearers, the distance between optical centers was coincided with the pupillary distance in 37.5%, and discrepant in 62.5%. 4. For the patients who were coincided with the pupillary distance, the proportion of exophoria decreased 53.33%, esophoria increased 20.0%. 5. For the changing of the quantity of Phoria in the low correction, the degree of exophoria decreased 1.11 prism diopters in the perfect correction, esophoria increased 0.39 prism diopters.