• Journal of Digital Convergence
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• v.12 no.12
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• pp.485-490
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• 2014

The purpose of this Study investigated corneal power, corneal astigmatism and corneal axis according to spherical equivalent of refractive error. We measured spherical equivalent, corneal power and corneal astigmatism in 100 subjects from January 2014 to July 2014. Measured spherical equivalent of refractive error were $-3.01{\pm}3.79D$, corneal power of $43.79{\pm}1.60D$ and corneal astigmatism of $-1.17{\pm}0.79D$ respectively. Prevalence of spherical equivalent of refractive error were as follows : myopes (61%), emmetropes (22%), hyperopes(17%). Corneal astigmatism of refractive error greater than +0.75D was 63% and prevalence of corneal astigmatism were as follows : with-the-rlue astigmatism (84.13%), against-the-rule astigmatism(9.52%) respectively. Corneal power by spherical equivalent increased from hyperopia to myopia. Between spherical equivalent of refractive error and the mean corneal power was significant correlation(r=-0.25, p=0.01). A correlation were found between corneal power and spherical equivalent of refractive error in adults. They have the highest distribution of prevalence myopia among the refractive error. When the refractive error was increased, we found that corneal power was steeper. It is recognized that this can be refractive error factor and correct visual function is considered.

• Journal of Korean Ophthalmic Optics Society
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• v.11 no.4
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• pp.345-350
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• 2006

The study of the visual acuity and refraction status was performed to the students of primary school using eyeglasses in Kyung Nam region, Korea. Two hundred sixty three subjects with various styles of ametropia were analyzed the visual acuity and refraction examination by the subjective and objective tools. The results of study were as follows; 1) According to the increase of age of subjects, the visual acuity of binocular in naked eyes was decrease. However ametropia was increase. 2) The high frequency of ametropia types in the binocular was simple myopia, and the next order of high frequency was mixed astigmatism, myopic compound astigmatism, simple hyperopia, and hyperopic compound, respectively. 3) On the power of spherical refractive error of ametropia, the high frequency was -1.00 diopter, and the next order of high frequency was -2.00 diopter, +2.00 diopter, -3.00 diopter, and so on, respectively. 4) According to the increase of subjects ages, the changes of dioptric power of myopic spheric power was increase. however the frequency of the boy and girl was similar results, also the dioptric values of refractive status in binocular was similar results. As the results of this study, we conclude that the relationship of the visual acuity and refractive error status in primary students using eyeglasses was improved.

• Journal of Korean Ophthalmic Optics Society
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• v.13 no.4
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• pp.37-42
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• 2008

Purpose: The objective of the study: At present, the spectacles, with its use as a medical aids or a fashion trimming, are recognized as one of the living necessities which can't be separated from human body. One of the features of spectacles is that it must be worn on any part of human body. Such a feature has to be satisfied under the condition an user keeps feeling comfortable with the rim of spectacles worn. In order to ensure meeting this condition, a criterion has to be arranged for the design of the rim of spectacles. In order to manufacture a rim of spectacles which allows an user to secure a comfortable range of vision as well as enhancing the feeling when to be worn, a manufacturing standard has to be established based on optical science. No precise rim of spectacles could be made from the manufacturing method depending on the manufacturer's sensibility. When the rim of spectacles was manufactured according to the incorrect standards, it may cause an user such a fatal result as myopia, hyperopia or astigmatism. Methods: This study focuses on providing a detailed explanation about the design of rim, which is the most important element during designing a rim of spectacles, making use of the optical elements of spectacles, and helping the manufacturers and the people who work in the spectacles-related business understand and recognize what is correct and exact and then leading them to establish a standard in respect to the manufacture and selection of spectacles. Results, Conclusions: Considering the fact there happen many errors in relation with the names of rim stipulated in the provisions of International Standards Organization (ISO), due to wrong interpretation by some of the rim manufacturers, the right interpretation should be given about the bridge which is directly connected to rim, so that the rims of spectacles manufactured in Korea could keep a favorable position in competing with the foreign products of same kinds.

• Journal of Korean Ophthalmic Optics Society
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• v.5 no.2
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• pp.79-85
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• 2000

This study was investigated the refractive state and the analysis of ametropic frequency among schoolchildren who were the three grade in W elementary school in Suwon. Total 488eye (244 persons) were examined by the trial-lens set and the questionary. Through Trial-Lens set verification, several factors related to ametropic frequency were obtained as the following. Among the 244 persons, the students who wear spectacles or need to wear spectacles were 27.3%, among the 27.3% students, the students who have low visual acuity below 0.3 were 6.3%. The ametropia eyes among the total eyes were 27.3%. Among ametropic eyes, myopia and hyperopia were 25.4% and 1.9%. Among the total ametropic errors were low refractive error were 71.4%, and middle refractive error were 28.6%. In ratio myopic frequency, it was statistically related to the refractive errors with the environments factors such as reading distance & habits, T.V watching distance. Among the students belonged to below 0.7 visual acuity, the wear spectacles students were 63.3%. The ratio of anisometropia was 3.4%.

• Journal of the Ergonomics Society of Korea
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• v.34 no.1
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• pp.29-43
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• 2015

Objective: The aim of this study is to develop management guidelines and a procedure for an anthropometric suitability assessment of the main control room (MCR) in nuclear power plants (NPPs). Background: The condition of the MCR should be suitable for the work crews in NPPs. The suitability of the MCR depends closely on the anthropometric dimensions and ergonomic factors of the users. In particular, the MCR workspace design in NPPs is important due to the close relationship with operating crews and their work failures. Many documents and criteria have recommended that anthropometry dimensions and their studies are one of the foremost processes of the MCR design in NPPs. If these factors are not properly considered, users can feel burdened about their work and the human errors that might occur. Method: The procedure for the anthropometric suitability assessment consists of 5 phases: 1) selection of the anthropometric suitability evaluation dimensions, 2) establishment of a measurement method according to the evaluation dimensions, 3) establishment of criteria for suitability evaluation dimensions, 4) establishment of rating scale and improvement methods according to the evaluation dimensions, and 5) assessment of the final grade for evaluation dimensions. The management guidelines for an anthropometric suitability assessment were completed using 10 factors: 1) director, 2) subject, 3) evaluation period, 4) measurement method and criteria, 5) selection of equipment, 6) measurement and evaluation, 7) suitability evaluation, 8) data sharing, 9) data storage, and 10) management according to the suitability grade. Results: We propose a set of 17 anthropometric dimensions for the size, cognition/perception action/behavior, and their relationships with human errors regarding the MCR design variables through a case study. The 17 selected dimensions are height, sitting height, eye height from floor, eye height above seat, arm length, functional reach, extended functional reach, radius reach, visual field, peripheral perception, hyperopia/myopia/astigmatism, color blindness, auditory acuity, finger dexterity, hand function, body angle, and manual muscle test. We proposed criteria on these 17 anthropometric dimensions for a suitability evaluation and suggested an improvement method according to the evaluation dimensions. Conclusion: The results of this study can improve the human performance of the crew in an MCR. These management guidelines and a procedure for an anthropometric suitability assessment will be able to prevent human errors due to inadequate anthropometric dimensions. Application: The proposed set of anthropometric dimensions can be integrated into a managerial index for the anthropometric suitability of the operating crews for more careful countermeasures to human errors in NPPs.

• Journal of Korean Ophthalmic Optics Society
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• v.14 no.3
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• pp.65-73
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• 2009

Purpose: This study was conducted to investigate the changes in distance refractive power and reading addition that occur after wearing corrective glasses for prebyopia. Methods: The subjects aged 42 to 75 years who had no ophthalmologic diseases and did not undergo cataract or retina surgery, had a corrected visual acuity of 20/20 and did not have a previous history of wearing corrective glasses for presbyopia. These subjects were divided into 3 groups: the control, reading spectacles and multifocals wearing group and they were measured for distance refractive power and reading addition at their visit. The maximum follow-up period was 73 months. Results: As for distance refractive power, the power tends to shift to hyperopia depending on age (r=0.486, p<.001) and 50.0% of the subjects increased plus power during this study period. Plus power Increments per year in distance refractive power in the reading spectacle wearing group were significantly different with control and multifocals wearing group (p<.05). On the other hand, the multifocals wearing group's increments were not different with control. Increments in reading addition were also increased in the reading spectacles group than in the control and multifocals wearing groups (p<.05). Conclusions: The age related hyperopic shift could be occurred in the elderly people, routine refraction is mandatory. And reading spectacles could induce an age related hyperopic shift and the additional need for reading addition that the prescription of multifocals may reduce changes in distance refractive power and reading addition.

• Journal of Korean Ophthalmic Optics Society
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• v.3 no.1
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• pp.103-113
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• 1998

Until now, the study of eye refractive error examination for high school students are a few report that in Korea. In particular, there is few report about the visual power for same group during several years. We compared the study of refractive error done this year with that reported three years ago at the same high school. From the these data, the distribution of ammetropia was investigated. The study of refractive error for high school students was also compared with those reported before for the Adults and the middle school student. When the visual power is refered to spherical equivalent, the 36% of the whole students examined above had emmetropia and the other part of them fumed out to be ammetropia which is classify to 60.6% belonged to myopia and 4.4% belonged to hyperpia. The ratio of myopia for this year students is increased in comparision with the students in 1995. The ratio of emmetropia for this year students is 7.4% higher, and the ratio of myopia for this year students is 4% higher, but the ratio of hyperopia is very lower than that for the adults in 1997. In the kind of refractive error, it is classified that a simple myopia is shown to highest ratio as a 28.6% of 1212 eyes examined, a compound myopic astigmatism to the next high ratio as a 22.4%, a simple myopic astigmatism as 14.4%, a simple hyperopic astigmatism as 3.1%, a mixed astigmatism as a 1.7%, a simple astigmatism as 1.2%, a compound hyperopic astigmatism as 1.2%, respectively. The percentage of an astigmatism is a 76.7% of total eyes examined if Cyl-0.25 Dptr is included to an astigmatism. On the other hand, The percentage of an astigmatism is a 45.6% of total eyes examined if Cyl-0.25 Dptr is excluded to an astigmatism. In the kind of astigmatism, the number of students had an astigmatism with the rule is about 4.5 times than that of astigmatism against the rule. From the result of comparision the right eye with the left eye, the right eye of the students had more a myopic refractive error than the left eye, which is same as adults' case, there is no difference in a refractive error between the boy students and the girl students.

• Journal of Korean Ophthalmic Optics Society
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• v.18 no.2
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• pp.143-148
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• 2013

Purpose: The aim of this study was to investigate the distribution of age and gender, types of intraocular lens (IOL), and refractive errors in subjects who had cataract surgery. Methods: 2,217 subjects who had cataract surgery were surveyed at an optometry clinic in Chungbuk from 2010 to 2012. Information about IOL was obtained from case history, reflective and retroillumination images IOL by auto refracto-keratometer. Refractive errors were determined by objective and subjective refraction. Results: The mean age of the subjects was $71.74{\pm}10.62$ years. The number of cataract surgeries increased from 524 persons in 2010 to 888 persons in 2012. Of the subjects surveyed, 52 persons (2.3%) were under the 40 years of age, 144 persons (6.5%) were in 50s, 404 persons (18.2%) were in 60s, 1,132 persons (51.1%) were in 70s, 485 persons (21.9%) were in above 80s. Cataract surgery was significantly prevalent in more female (1,338 persons, 60.4%) than in male (879 persons, 39.6%). Types of IOL were 2,141 persons (96.6%) for monofocal lens, special IOLs such as multifocal, accommodative and toric lens were 76 persons (3.4%). The distribution of refractive errors after cataract operation were 1,588 eyes (38.5%) for simple myopic astigmatism, 327 eyes (7.9%) for simple hyperopic astigmatism, 601 eyes (14.6%) for mixed astigmatism, 1,240 eyes (30.0%) for myopia, 136 eyes (3.3%) for hyperopia, and 234 eyes (5.7%) for emmetropia. The uncorrected and best corrected visual acuity of the subjects were $0.55{\pm}0.25$ and $0.80{\pm}0.23$, respectively. Conclusions: The prevalence of cataract surgery increased with age until 70s years of age, it was more prevalent in men than women over 60s, and frequency of special types of IOL were low. Most cataract surgeries left residual refractive errors. Therefore even after cataract surgery it may need spectacles for better vision at either distance or near.

• Journal of Korean Ophthalmic Optics Society
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• v.5 no.1
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• pp.107-116
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• 2000

This study is of investigation of refraction error, spectacles and contact lenses wearing state, visual acuity test, ophthalmologic common sense and vision care, using questionnaire study for 850 male and female high school students in Kunsan and Chongup City, Cheolla North Province. The results are as follows: 1. Among the 823 answerers, emmetropia is 18%, myopia is 55.1%, and hyperopia is 7%, respectively. 2. Among the 837 answerers, 381 students(45.5%) wear spectacles or contact lenses. Among the 381 students who wear spectacles or contact lenses, 78% wear only spectacles, 4% wear only contact lenses and 18% wears spectacles sometimes or contact lenses sometimes. 3. The places where the answerers had visual acuity test to wear spectacles or contact lenses are optical shop(64.7%), hospital(28.3%), unchecked(4.2%) and the others(2.7%). The places where the answerers had visual acuity test to change their spectacles or contact lenses are optical shop(82%), hospital(28.3%), unchecked(6.6%) and the others(1.9%). 4. As for the period of visual acuity test, from 6 months to one year is 54.1%, within 6 months is 9.2%, from one year to two years is 29.5%, and more than two years is 7.2%. 5. The contact lens wearers purchased their contact lenses at optical shops(94%) and at hospital(6%). 6. The reasons why they like wearing contact lenses are their appearance(51.2%), convenience in physical excercise(23.l%), lighter weight than spectacles(9.8%) and the others(15.7%). 7. As for the spectacles frame they like, plastic frame is 24.4%, gold or silver plated frame is 43.4%, coloured frame is 32.1%. 8. As for the considerations in choosing spectacles frame, their design is 37%, their quality is 36%, their price is 14.7% and their brand is 12.5%. 9. As for the period for changing spectacles, 10.5% is within 6 months, 57.3% is 6months to 1 year, 22.4% is 1 year to 2 months and 9.6% is more than 2 years. 10. There is a false fact, in Korea, that even though one has his poor eyesight, not wearing custom is helpful for the eyesight recovery. As for their conviction of the false fact, 10.5% of the answerers have 100% conviction, 22.5% of them have 22.5% conviction, 49.5% of them have 50% conviction and 17.5% of them don't have any conviction. 11. 48.5% of the answerers are interested in their vision care while 51.5% of them are not interested at all. As for the way of vision care, the vision-care way to keep enough distant when they are watching TV, when they are using computers and when they are reading, is 49% while the vision-care way such as hypogastric breathing or eye massage is 11%. And alimentotherapy is 4% and the rest who are not interested in vision care is 36%. 12. When they come to an age, the students who want vision correction operation are 45.9% while the students who do not want it are 27%. The students who do not have any idea about the operation are 27.1%

• Journal of Korean Ophthalmic Optics Society
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• v.5 no.1
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• pp.131-138
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• 2000

We compared the study of refractive error of the eyes done in 1998 with that reported three years ago at any high school in the north Kyungki. From the these data, the distribution of ammetropia was investigated. The study of refractive error for high school students was also compared with those reported before for the Adults and the middle school student. When the refractive error is refered to spherical equivalent, the 40.6% of the whole students examined above had emmetropia and the other part of them(59.4%) turned out to be ammetropia which is classified to 46.4% belonged to myopia and 13.0% belonged to hyperpia. The ratio of emmetropia for the students in 1998 is 4.4% lower, and the ratio of hyperopia is 4.3% lower, but the ratio of myopia for the students in 1998 is 8.7% higher than that for the student in 1995. In the kind of refracive error, it is classified that a simple myopia is shown to highest ratio as a 23.6% of 6143 eyes examined, a compound myopic astigmatism to the next high ratio as a 17.4%, a simple myopic astigmatism as 10.9%, a simple hyperopic astigmatism as 9.8%, a simple astigmatism as 7.1%, a compound hyperopic astigmatism as 2.2%, a mixed astigmatism as a 1.8%, respectively. The percentage of an astigmatism is a 69.6% of total eyes examined if Cyl-0.25 Dptr is included to an astigmatism. On the other hand. The percentage of an astigmatism is a 45.0% of total eyes examined if Cyl-0.25 Dptr is excluded to an astigmatism. In the kind of astigmatism, the number of students had an astigmatism with the rule is about 5.6 times than that of astigmatism against the rule. From the result of comparison the right eye with the left eye, the right eye of the students had more a myopic refractive error than the left eye, which is same as adults' case.