• Journal of Korean Ophthalmic Optics Society
• /
• v.18 no.4
• /
• pp.365-371
• /
• 2013

Purpose: In this study, we evaluated the physical and thermal properties of the compositions made by blending glass fiber (GF) of different contents into glass fiber polyamide-66, and investigated if the compositions applying to the glasses frame to replace the TR-90, which is polyamide-12 resin used as an injection-type spectacle frame material. Methods: To investigate the characteristics change of polyamide-66 (PA-66) compositions with the change of the content of glass fibers, we produced a composition of the content by using a twin-screw extruder. The mechanical strength of the composition production was measured and coating properties as well as cutting processability were evaluated. We evaluated the applicability of the glasses frame by comparison the results of new compositions with characterizations of traditional TR. Results: For the results of the characterization of Polyamide-66/GF composition, we found that the higher increase of content of the glass fiber, the less mold shrinkage rate, and the mechanical strength was increased. Tensile strength increased from $498kg/cm^2$ for 0 wt% of the content of the glass fibers to $849kg/cm^2$ for 30 wt% of the content of the glass fibers. As a result of a coating evaluation, the strength of coating was 4B in the GF 5wt% and 5B, which was extremely good coating characteristics, in the over than GF 5 wt%. Conclusions: In case that 30 wt% of the glass fiber was blended, the mechanical strength was greatly improved, the hardness was increased, injection temperature increased due to increase of the viscosity, and the flow mark of the product may occur. The paint coating of PA-66 blended with glass fiber was all excellent. With general evaluating physical properties and workability properties it was determined that around 10 wt% of the content of the glass fibers was possible to apply a spectacle frame.

• Journal of Korean Ophthalmic Optics Society
• /
• v.20 no.3
• /
• pp.311-318
• /
• 2015

Purpose: This study was designed to investigate the prevalence rate of refractive error with gender and age presenting visual acuity of primary student in Jeonnam. Methods: Subjective refraction, objective refraction and visual acuity test were examined on 735 primary school children who ages of 8~13 years lived in Jenman. Presenting visual acuity test was using Han's visual acuity chart and objective refraction was carried out using auto-refractometer. Results: The presenting visual acuity was 0.1 worse in the eye of 54(7.3%) students and 49(7.3%) of them wearing the glasses. The rate of the wearing glasses were 79.3% in 0.125~0.25 visual acuity, 64.2% in 0.3~0.5 visual acuity and 61.6% in 0.6~0.8 visual acuity. It was appeared that 269(36.6%) of them were emmetropia, 321(43.7%) of them were myopia and 56(7.6%) of them were hyperopia, and 89(12.1%) of them were astigmatism. The prevalence rate of myopia was the highest and followed by the prevalence rate of astigmatism. The low degree of myopia occupied the most and the medium degree of myopia showed the tendency of increase as the students get olds. The prevalence rate of the hyperopia showed the tendency of decrease as the students get olds. The prevalence rate of with the rule astigmatism were 50.6% students and against the rule astigmatism were 48.3% of students. Conclusions: The present study reveals the considerable prevalence rates, 466(63.4%) of included subjects, of refractive errors among primary students in Jeonnam province. The rate of the wearing glasses were 313(42.6%). The prevalence of myopia increases as the students get older. Therefore students of visual management is considered necessary through the visual acuity test and refractive examination.

• The Korean Journal of Vision Science
• /
• v.20 no.4
• /
• pp.561-568
• /
• 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
• /
• v.20 no.2
• /
• pp.247-253
• /
• 2015

Purpose: The purpose of this study was to compare and analyze the ocular surface and the palpebral conjunctiva of categorized subjects, which were divided into normal eye group and dry eye group, by using a thermal camera. Methods: Subjects were 144 eyes of 72 normal university students, who didn't have any corneal disease, abnormal lacrimal ducts, medical records regarding ocular surgeries, or experience of using contact lens. Subjects were divided into two groups, which were normal eye group and dry eye group, based on the results of TBUT, Schirmer I test, and McMonnies test. After categorizing the subjects, the temperature of the subjects' ocular surface and the palpebral conjunctiva were measured and analyzed by using a thermal camera (Cox CX series, Answer co., Korea). Results: In the normal eye group's Central Ar.1, Nasal Ar.2, Temporal Ar.3, Superior Ar.4, Inferior Ar.5, the measured amount of temperature change on each area was $-0.13{\pm}0.08$, $-0.14{\pm}0.08$, $-0.12{\pm}0.08$, $-0.14{\pm}0.08$, $-0.10{\pm}0.09(^{\circ}C/sec)$. The dry eye group's results were $-0.17{\pm}0.08$, $-0.16{\pm}0.07$, $-0.16{\pm}0.08$, $-0.17{\pm}0.09$, $-0.15{\pm}0.08(^{\circ}C/sec)$. When compared with the normal eye group, the values of Ar.1, Ar.3, Ar.5 were significantly different in the dry eye group(p<0.05). The amount of temperature change, which was observed on the palpebral conjunctiva(Ar.1:central, Ar.2: nasal, Ar.3: temporal) of the normal eyes, measured by thermography, was $34.36{\pm}1.12$, $34.17{\pm}1.10$, $34.07{\pm}1.12^{\circ}C$ on each area. Same values taken from the dry eye group was $33.55{\pm}0.94$, $33.43{\pm}0.97$, $33.51{\pm}1.06^{\circ}C$ on each area. The values of Ar.1, taken from the dry eye group, had a significant difference, compared to the values of the normal eye group(p=0.05). Conclusion: The temperature of the ocular surface decreased faster on the dry eyes, compared to the normal eyes. The temperature measured on the palpebral conjunctiva of the dry eyes were also lower than the normal eyes. The temperature changes on the ocular surface, observed with a thermal camera, were objective values to assess the stability of tear films, and might provide useful data for studies related to dry eye syndrome.

• Journal of Korean Ophthalmic Optics Society
• /
• v.20 no.4
• /
• pp.491-499
• /
• 2015

Purpose: This study was to examine how decline of visual function affects visual perception by assessing visual perception after improving visual function through visual training, and observing the change in the cognitive ability of visual perception. Methods: This study analyzes the visual perceptual evaluation (TVPS_R) of 23 children below age 13($8.75{\pm}1.66$) who have visual abnormalities, and improves visual function after conducting vision training (vision therapy) of the children. Results: Convergence increased from average $3.39{\pm}2.52{\Delta}$ (prism) to $13.87{\pm}6.04{\Delta}$ in the measurement of long-distance disparate points, and from average $5.48{\pm}3.42{\Delta}$ to $18.43{\pm}7.58{\Delta}$ in the measurement of short-distance disparate points. Short-distance diplopia points increased from $25.87{\pm}7.33cm$ to $7.48{\pm}2.87cm$, and as for accommodative insufficiency, short-distance blur points increased from $19.57{\pm}7.16cm$ to $7.09{\pm}1.88cm$. In the visual perceptual evaluation performed before and after improving visual function, 6 items except visual memory showed statistically significant improvement. By order of significant improvement, response gap was highest with $17.74{\pm}16.94$(p=0.000) in visual closure, followed by $15.65{\pm}17.11$(p=0.000) in visual sequential-memory, $13.65{\pm}16.63$(p=0.001) in visual figure-ground, $12.74{\pm}18.41$(p=0.003) in visual form-constancy, $6.48{\pm}10.07$ (p=0.005) in visual discrimination, and $4.17{\pm}9.33$(p=0.043) in visual spatial-relationship. In the visual perception quotient that added up these scores, the response gap was $15.22{\pm}8.66$(p=0.000), showing a more significant result. Conclusions: Vision training enables efficient visual processing and improves visual perceptual ability. It was confirmed that improvement of visual function through visual training not only improves abnormal visual function but also affects visual perception of children such as learning, perception and recognition.

• Journal of Korean Ophthalmic Optics Society
• /
• v.18 no.2
• /
• pp.125-136
• /
• 2013

Purpose: The aim of this study was to investigate the effect of improving read speed with color filter or without color filter to improve reading disorder of teenager who were diagnosed as Meares-Irlen syndrome through survey inspection with Meares-Irlen syndrome visual stress (MISViS) score. Methods: MISViS subjects were selected from screening survey MISViS results given above 2.13 in the clinical criteria scores (MISViS score). Reading speed were measured quickly and efficiently the rate of reading via test in which randomly ordered common words are read aloud during a minute. Each of the subjects were worn a filter of the lowest concentration in each color filter group composed of 15 groups. Results: MISViS score of MISViS group and control group were 2.57 and 0.66, respectively. Results of reading speed with filter and without filter in MISViS group were $102.27{\pm}27.86$ wpm and $118.87{\pm}26.99$ wpm (p=0.001), respectively, as well as were $132.93{\pm}6.88$ wpm and $133.43{\pm}6.64$ wpm (p=0.131) in the normal group. Associated with error changes with filter and without filter between two groups, skipping in MISViS Group were from $0.25{\pm}0.62$ times to 0 times (p=0.191), Errors were from $1.83{\pm}1.69$ times to $0.17{\pm}0.38$ times (p = 0.004) and, repetitions were 0. skipping in control group were 0 times, errors were from $0.21{\pm}0.43$ times to $0.07{\pm}0.27$ times (p=0.336) and, repetitions were from $0.14{\pm}0.36$ times to 0 (p=0.165). The filter of blue series chosen in MISViS group had higher percentage (40%), whereas, subjects in normal group were more likely to prefer the filter of gray color (29%). Conclusions: This study showed that MISViS score have been used as a significant diagnosis for Irlen syndrome screening. This study found that wearing suitable color filter for MISViS patients were useful to improve learning with regard to reading. Unique color filter selection for MISViS subjects must be carefully considered since fit color filter are different personally.

• Journal of Korean Ophthalmic Optics Society
• /
• v.18 no.3
• /
• pp.347-356
• /
• 2013

Purpose: To evaluate the visual acuity and visual performance after implantation of a aspheric multifocal (ReSTOR$^{(R)}$ SN6AD3) intraocular lens (IOL). Methods: Nineteen cataract patients (30 eyes) implanted with an aspheric multifocal IOL (ReSTOR$^{(R)}$ SN6AD3) either unilaterally or bilaterally were participated. Visual acuity (VA) and objective optical performance were evaluated at the time of preoperation, 1 week, 1 month, and 3 month after operation. At 3 month of post-operation, objective visual performance were measured and compared with the 38 eyes of 20 age-matched normal control. Distance VA was measured by using the ETDRS LCD chart and intermediate and near visual acuity were measured using Jaeger chart. Objective visual performance was assessed preoperatively and 1 week, 1 month and 3 month postoperatively using a double-pass system (Optical Quality Analysis System) with a 4-mm pupil diameter, the OSI (objective scatter index), MTF (modulation transfer function) cut off and strehl ratio. At 3 month of post-operation, visual acuity and visual performance compared with age matched normal control. Results: The uncorrected distance VA, OSI, MTF cut off and strehl ratio were significantly improved (p<0.05) until 1 month postoperatively. Visual performance of MTF cut off and strehl ratio after 3 month of operation were significantly improved compared to the normal control (p=0.063, p=0.103 respectively), however, OSI was higher than normal control. Patients implanted with aspheric multifocal IOL were satisfied with distance and near VA however, were unsatisfied with intermediate VA and reported glare and halos. Conclusions: The visual performance reaches to a stable condition in 1 month of implantation of aspheric multifocal IOL and improved to the level of age-mated normal patients. Also patients were satisfied with their quality of vision, however, intermediate VA, glare and halos were reported as complications.

• Journal of Korean Ophthalmic Optics Society
• /
• v.18 no.2
• /
• pp.213-229
• /
• 2013

Purpose: The Nutrient intake during the growth period is a critical factor for the development of the vision. In this study, we have analyzed the nutrient that has a correlation with the decrease of induced visual impairment. In addition, we investigated visual acuity and correlation of the nutrient in the higher-income youth and low-income youth. Methods: We used the Korean National Health and Nutrition Examination Survey 2010 document. The Korean National Health and Nutrition Examination Survey didn't show the clear standard of carbohydrates and fats, so we used the data from the Ministry of Food and Drug Safety standards with each 330 g, 51 g. In order to compare the correlation of nutrients and refraction, Nutrients has been classified macronutrients(energy, dietary fiber, protein, carbohydrate, fat), fat-soluble vitamins (vitamin A), water-soluble vitamins (vitamin C, riboflavin, niacin), trace minerals (iron), minerals (calcium, phosphorus, sodium, potassium) and water. Results: We investigated the correlation between refraction and nutrients on average about 328 subjects belonging to the high-income group. The fat intake was $54.21{\pm}32.60$ g, and it was about 2~10 times less than the recommended daily intake (112-540 g). Refractive power and fat intake showed a statistically significant correlation (O.D:p=0.033, O.S:p=0.029). We investigated the correlation between refraction and nutrients on average about 309 subjects belonging to the lowincome group. The phosphorus showed higher ingested by the $1118.75{\pm}501.98$ mg, and the sodium showed intake more than three times recommended intake by the $3705.24{\pm}2089.42$ mg. In addition, unlike other macro mineral it showed that was a correlation on the refraction by the 0.031. Conclusions: A broad variety of taking nutrition and good eating habits at the time of growth seems to have an effects to the good growth and vision and the senescence inhibition of vision.ave an effect to the good growth, the good vision and the senescence inhibition of vision.

• Journal of Korean Ophthalmic Optics Society
• /
• v.19 no.4
• /
• pp.445-455
• /
• 2014

Purpose: By investigating the characteristics of the students ophthalmic optics under bachelor's degree course in academic credit bank system, this study aimed to utilize this survey as a basic material for the operation and the improvement of academic credit bank system as the continued education for opticians. Methods: A questionnaire survey for the characteristics of the students was conducted on 98 bachelors who registered in the academic credit bank system and an analysis was made out of the result. Results: As the purpose of selecting the academic credit bank system, acquisition of bachelor's degree took the major portion (51.0%); for information route, school or superior at work took the major portion (33.7%); and for educational institution, alma mater took the major portion (31.6%). Family cooperation (72.4%) to the students in the academic credit bank system was higher than workplace cooperation (46.9%) or social cooperation (39.8%). For the time required for the bachelor's degree course in the academic credit bank system, 2 semesters (55.6%) took the major portion, and 38.9% for entering graduate school and 5.6% for university transfer. The result showed a significant difference in the information route for the academic credit bank system (p<.05), selection criteria for educational institution (p<.05) and workplace cooperation (p<.01) depending on the age. It showed a significant difference in the selection purpose for the academic credit bank system (p<.01), average attendance day (p<.05), workplace cooperation (p<.01) and difficulties (p<.01) depending on working place. It showed a significant difference in the selection criteria for educational institution (p<.01) and family cooperation (p<.05) depending on the academic system of their alma mater. It showed a significant difference in the information route (p<.05), the selection criteria for educational institution (p<.01) and workplace cooperation (p<.05). Conclusions: It is necessary for optometrists to study and pay more attention to continuing education, and the operation and support for the academic credit bank system should be made in consideration of the characteristics of students.

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