• Journal of Korean Ophthalmic Optics Society
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• v.13 no.2
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• pp.59-62
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• 2008

Purpose: This study was designed to investigate the time-dependent changes of visual acuity after alcohol ingestion. Methods: Both the subjective and objective refraction, distant contrast sensitivity, and three needle tests were carried out at 1 and 3 hours after alcohol ingestion. Results: It was found that the degree of myoptization increased as the blood alcohol level increased in the range of average -0.25D ~ -0.35D when tested 1 and 3 hours after alcohol ingestion. Under the same test conditions the increase in blood alcohol resulted in the reduction in the function of dynamic stereopsis. However, the variation in contrast sensitivity was found to be insignificant for all spatial frequencies. Conclusions: The optician has to be well aware of the fact that alcohol could affect the visual acuity and functional tests, therefore inquiring of the alcohol ingestion prior to visual test can be necessary.

• Journal of Korean Ophthalmic Optics Society
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• v.14 no.4
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• pp.71-75
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• 2009

Purpose: This study was designed to investigate the condition of refractive correction and heterophoria and monocular pupillary distance on myopic elementary school children wearing glasses in Gwangju city. Methods: Subjective refraction and objective refraction were examined after investigating heterophoria and monocular pupillary distance on 145 (290eye) elementary school children wearing myopia-corrected glasses. Results: 1. Anisometropia > 2.00 D was present in 4 children (3%). 2. 9 anisometropia (47%) were present in 19 undercorrected visual acuity boy wearers. and 16 anisometropia (64%) were present in 25 undercorrected visual acuity girl wearers. 3. Among the 67 myopic glasses boy wearers, the distance between optical centers was coincided with the pupillary distance in 30% (Oculus Uterque), and discrepant in 70% (Oculus Uterque). Among the 78 myopic glasses girl wearers, the distance between optical centers was coincided with the pupillary distance in 23% (Oculus Uterque), and discrepant in 77% (Oculus Uterque). The mean optical center distance was longer than the pupillary distance on both boy and girl wearers 4. The result of measured heterophoria revealed 14% for orthophoria, 63% for exophoria, 23% for esophoria at far distance and 10% for orthophoria, 76% for exophoria, 14% for esophoria at near distance. Conclusions: Correct refractive test and monocular pupillary distance must be examined because incorrect refractive test and pupillary distance induce asthenopia and heterophoria.

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

• Journal of Korean Ophthalmic Optics Society
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• v.19 no.2
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• pp.261-270
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• 2014

Purpose: To study the effect of an artificially induced dioptric blur on acuity and contrast sensitivity using the $Optec^{(R)}$ 6500. Methods: Healthy 31 subjects aged $22.90{\pm}1.92$ (male 16, female 15) who were recruited from university students with 6/6 (20/20) or better corrected visual acuity and normal binocularity. They were measured objective and subjective refraction for full correction and dioptric blur using 0.00 ~ +3.00 D (+0.50 D steps) trial lenses and trial frame. They were measured binocularly visual acuity and contrast sensitivity with the $Optec^{(R)}$ 6500 (Stereo Optical Co., Inc., Chicago, Illinois, USA) under day conditions (photopic condition, $85cd/m^2$). Results: The higher dioptric blur, the less distance visual acuity and decrease rate of visual acuity. The higher dioptric blur, the less contrast sensitivity at all frequencies, and the peak of contrast sensitivity was shifted from middle frequency (6 cpd) to low frequency (1.5 cpd). When the visual acuity was best visual acuity to 0.77, there was the peak point at 6 cpd which was normal contrast sensitivity peak point. Conclusions: If the low refractive error is uncorrected or the refractive error is inappropriate, the contrast sensitivity is decreased and the peak point of contrast sensitivity frequency is shifted abnormally though small uncorrected refractive error. So it will be considered that regular eye test and decision of refractive error correction is important.

• Journal of Korean Ophthalmic Optics Society
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• v.13 no.1
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• pp.77-81
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• 2008

Purpose: This study was to investigate the refractive state of an asian population (male: 39, female: 53) from 21 to 30 years old who visited the A optical shop at jongnogu in seoul. Methods: The visual acuity test was performed by the object and subject method. Results: Among the 184 eyes, myopia is 83.16% and emmetropia is 16.84%, respectively. As for the equivalent spheric power of myopic abnormal refractive eyes, the -m0.5Dt < spheric equivalent ${\leq}$ -2.00Dt was 40.53%, the -2.00Dt < spheric equivalent ${\leq}$ -6.00Dt was 51.63% and anything over the -6.00Dt was 7.85%. The percentages of with-the-rule, against-the-rule and oblique astigmatism among people with astigmatism were 46.67%, 35.56% and 7.77%, respectively. The average of pupillary distance in male (64.5${\pm}$2.9 mm) was greater than that in female (61.9${\pm}$2.3 mm). Conclusions: Korean opticians were provided some useful information about making up a prescription by this research.

• Journal of Korean Ophthalmic Optics Society
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• v.6 no.1
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• pp.71-76
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• 2001

In this study, the variation of astigmatism axis according to the age was studied 4227 eyes of healthy eyes. The refractive errors were measured by objective and subjective refraction. The astigmatism among the total eyes was 76.5%. With-the-rule, against-the-rule and oblique astigmatism were 51.4%, 31.7% and 16.9%, respectively. The frequency of with-the-rule was the highest and against-the-rule was the lowest of all the astigmatism in the refractive error. In relation to the age and astigmatism, the with-the-rule was 68.3% in the 10's age group which was the highest among the astigmatism and the against-the-rule was 10.3% in the 50's age group and upward which was the lowest among the astigmatism. The difference in the with-the-rule and against-the-rule ratio was a little in the 30's age group. As they aged, the tendency of the with-the-rule was increased between 10's and 20's age group continually. And the tendency of the against-the rule was increased between 30's and 50's age group and upward. There was a decrease in with-the-rule and an increase in against-the-rule, with the age increase. The oblique astigmatism relationship to age could not be determined.

• Journal of Korean Ophthalmic Optics Society
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• v.7 no.2
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• pp.61-65
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• 2002

This study examines how the average presbyopic additions and eye refraction state of old ages in city may be different to that island. There were 677 of the old who were 50 or over 90 in the sample. The visual acuity test was done by objective and subjective methods and used for near-chart program. The far-point refraction state and power of the additions lens results were as follows ; 1. Of far-point refraction state in city peoples; male: emmetropia 10%, myopia 17%, hyperopia 19%, mixed astigmatism 38%, etc. 16% female : emmetropia 20%, myopia 20%, hyperopia 20%, mixed astigmatism 27%, etc. 13% 2. Of far-point refraction state in island villages ; male : emmetropia 13%, myopia 17%, hyperopia 22%, mixed astigmatism 40%, etc. 8% female : emmetropia 7%, myopia 13%, hyperopia 26%, mixed astigmatism 44%, etc. 10% 3. Average presbyopic additions states has been presented no discrimination ; male: 50 to 60 : +1.25 or +1.50D, 61 to 65 : +1.75 or + 2.00D, 66 to 70 : +2.25 or +2.50D 71 to 75 : +2.75 or +3.00D, 76 to 80 : +3.25 or +3.50D, over81 : +3.75D female : 50 to 60 : +1.25 or + 1.50D, 61 to 65 : +1.75 or + 2.00D, 66 to 70 : +2.25 or +2.50D 71 to 75 : +2.25 or + 2.50D, 76 to 80 : +2.75 or +3.00D, over81 : +2.75 or +3.00D 4. Under the condition of wearing lens, the average working time was 1 or 2 hour but some people used over 5 hours. 5. Generally, it has been investigated the old ages peoples has ocular diseases and cataract was the most common.

• Journal of Korean Ophthalmic Optics Society
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• v.7 no.2
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• pp.41-45
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• 2002

To study the ametropia and the sort of glasses, especially progressive multifocal lens, for near purpose on Middle aged & Manhood. 500 adults were tested by the object and subject methods. Among the 500 adults, myopia is 22.4%, hyperopia is 61.4%, and emmetropia is 16.2%, respectively. In test of astigmatism, the amount of astigmatism for the age of forty one to under forty five with-the rule is 28%, the amount of astigmatism against-the rule is 43% and the amount of astigmatism with oblique is 11%, respectively. Whereas, the amount of astigmatism for the age of fifty six to under sixty with-the rule is 10%, the amount of astigmatism against-the rule is 71% and the amount of astigmatism with oblique is 19%, respectively. With-the-rule decreased with increasing age while against-the-rule increased with increasing age. The oblique astigmatism relationship to age could not be determined. The ratio of the progressive multifocal lens was 67.3% for male and 35% for female.

• Journal of Korean Ophthalmic Optics Society
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• v.11 no.2
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• pp.131-135
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• 2006

The purposes of this study is examining a wearing tendency of a progressive multifocal lens. We measured refractive error values using subjective and objective refraction method with subjects in 40-65 ages. Also, we investigated and analyzed distribution of addition power and wearing tendency of progressive multifocal lens. Detected addition powers were ranged of +0.75D - +3.00D. In case of average addition, they were detected with +1.18D in 40's, +1.55D - +1.97D in 50's and +2.38D in above 61's age. The distributions of visual ability at a distant were measured that the hyperopia and hyperopic astigmatism 43%, the myopia and myopic astigmatism characteristic astigmatism 7% appeared highly with 36%. The male who uses the interior aspect multi focal lens with the short-range work were appeared the male 20%, the woman 19%.

• Journal of Korean Ophthalmic Optics Society
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• v.15 no.3
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• pp.219-225
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• 2010

Purpose: Usefulness in predicting the power of spherical rigid gas-pearmeable (RGP) lenses prescription using dioptric power matrices and arithmetic calculations was evaluated in this study. Noncycloplegic refractive errors and over-refractions were performed on 110 eyes of 55 subjects (36 males and 19 females, aged $24.60{\pm}1.55$years) in twenties objectively with an auto-refractometer (with keratometer) and subjectively. Tear lenses were calculated from keratometric readings and base curves of RGP lenses, and the power of RGP lenses were computed by a dioptric power matrix and an arithmetic calculation from the manifest refraction and the tear lens, and were compared with those by over-refractions in terms of spherical (Sph), spherical quivalent (SE) and astigmatic power. Results: The mean difference (MD) and 95% limits of agreement (LOA=$MD{\pm}1.96SD$) were better for SE (0.26D, $0.26{\pm}0.70D$) than for Sph (0.61D, $0.61{\pm}0.86D$). The mean difference and agreement of the cylindrical power between matrix and arithmetic calculation (-0.13D, $-0.13{\pm}0.53D$) were better than between the others (-0.24D, $0.24{\pm}0.84D$ between matrix and over-refraction; -0.12D, $0.12{\pm}1.00D$ between arithmetic calculation and over-refraction). The fitness of spherical RGP lenses were 54.5% for matrix, 66.4% for arithmetic calculation and 91.8% for over-refraction. Arithmetic calculation was close to the over-refraction. Conclusions: In predicting indications and powers of spherical RGP lens fitting, although there are the differences of axis between total (spectacle) astigmatism and corneal astigmatism, Spherical equivalent using an arithmetic calculation provides a more useful application than using a dioptric power matrix.