• Journal of Korean Ophthalmic Optics Society
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• v.18 no.3
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• pp.291-295
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• 2013

Purpose: The purpose of this study was to investigate the effect of under and over refractive correction on visual acuity performance and the variation of the visual performance measurement using two different visual acuity charts. Methods: Ten young adults, aged between 19 and 25 years old, were recruited. Inclusion criteria: no history of ocular injury or pathology with a best-corrected visual acuity of 6/6 on dominant eye. The over and under refractive corrections were induced using minus and plus spherical ophthalmic lenses in 0.50 D steps up to 3.00 D; as well as using three axis orientations of cylindrical ophthalmic lenses ($45^{\circ}$, $90^{\circ}$ and $180^{\circ}$) in 0.50 D steps. The variation of visual acuity performance measurements was investigated using Bailey-Lovie LogMAR chart and Landolt C chart. Results: The visual acuity changes with lenses were significantly different between two charts [F = 49.15, p < 0.05 with plus spherical ophthalmic lenses and F = 174.38, p < 0.05 with minus spherical ophthalmic lenses]. The visual acuity changes with three different cylindrical axis showed no significant difference between Bailey-Lovie LogMAR chart [F = 2.35, p > 0.05] and Landolt C chart [F = 3.12, p = 0.05]. Conclusions: The over and under refractive correction affected the visual acuity performance differently. The Landolt C chart and Bailey-Lovie LogMAR chart demonstrated variation in measurements.

• Journal of Korean Ophthalmic Optics Society
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• v.12 no.2
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• pp.95-106
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• 2007

The purpose of this study was to investigate effect of spectacle correction therapy instead of occlusion therapy for refractive amblyopia treatment. Spectacle correction were prescribed to give the same effect as a occlusion therapy by under correction for normal eye and there was no additional treatment but only spectacle correction for hyperopic amblyopia. The results can be summarized as follows: 1. In hyperopic amblyopia after correction, initial visual acuity($Mean{\pm}SD$) was $0.36{\pm}0.13$ and final visual acuity($Mean{\pm}SD$) was $0.82{\pm}0.23$. 2. Regardless with age, there was significant differences between initial acuity and final acuity, it shows improvement in visual acuity after spectacle correction treatment. 3. Initial correction age did not influence the length of treatment and success rate of treatment, so that ambyopia correction effect not related with age. 4. Compared with initial visual acuity with final visual acuity, initial visual acuity was in proportion to final visual acuity. 5. Incidence was higher in hyperopia and hyperopic astigmatism than myopia and myopic astigmatism in refractive amblyopia group and the therapy was more effective for hyperopia and hyperopic astigmatism than myopia and myopic astigmatism. 6. Treatment was effective even for children who is older than 8 years.

• Journal of Korean Ophthalmic Optics Society
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• v.9 no.2
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• pp.345-352
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• 2004

We investigated the effect of age at initial correction, of 44 refractive amblyopic patients duration of correction on corrected visual acuity with the lapse of time for mean 33months(3months-59months). Full cycloplegic corrections were prescribed at the initial visit to all subjects. The distribution of initial corrected visual acuity was 0.02 to 0.5. Age at initial correction varied from 3 years to 12 years. The refractive error appeared to have the greatest influence on the visual outcome, showing continuous visual improvement after initial correction. But the age at initial correction did not appear to influence on the initial and final corrected visual acuity showed a significant difference, irrespective of age at the initial correction Or degree of anisometropia.

• Journal of Korean Ophthalmic Optics Society
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• v.12 no.3
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• pp.117-120
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• 2007

The actual condition of periodic visual acuity testing for 304 undergraduate students were investigated for the purpose of prepared some fundamental data on the development of the eye-health education program and conducting a practical application. Many undergraduate students (59.21%) had not been tested periodic visual acuity testing. The ratio of periodic visual acuity testing for female was higher than male. There was statistical significant difference dependence on the native place, the educational system, and the division of major. The ratio of periodic visual acuity testing for undergraduate students from city was 43.07%, from rural area was 24.32% (p<0.05). According to the educational system, the ratio of periodic visual acuity testing of university students was 65.71%, college students was 27.64% (p<0.001). The ratio of periodic visual acuity testing of undergraduate students who have corrected their visual acuity was 50.25%, while that of students who have not corrected was 23.36% (p<0.001).

• Journal of Korean Ophthalmic Optics Society
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• v.17 no.1
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• pp.53-58
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• 2012

Purpose: The purpose of this study was to predict the amount of astigmatism through logMAR visual acuity by Jin's chart at best vision spherical power and to compare availability of astigmatism expectation by Jin's and beam project chart. Methods: LogMAR and decimal visual acuity were measured for 150 college students and visual acuity and compared the amount of astigmatism under full correction. Results: Jin's chart was showed marked differences at least more than 0.25 D intervals per line than beam project chart. Correlation with the amount of astigmatism was higher the logMAR visual acuity r = 0.8578 than decimal visual acuity r = -0.7199. Conclusions: LogMAR visual acuity at best vision spherical power was able to predict to amount of astigmatism and Jin's chart was easier than beam project chart to predict difference of each lines.

• 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.12 no.3
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• pp.83-87
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• 2007

This study was classified and compared astigmatism's refractional abnormal degrees with visual acuity state of full correction which turned on axises of only 5 degree, 10 degree, and 15 degree. Subjects of this study were 57 college students (114 eyes) who had neither eye diseases nor binocular abnormality, were from their twenties to fifties, with myopia. It appeared that 30.8% of subjects who had astigmatism wore glasses with wrong axis of astigmatism. After accurate correction of the visual acuity and degrees of astigmatism, when we moved to corrected axises at 5 degree, 10 degree, 15 degree, failure of visual acuity with one line or more were 56.1%, 84.2%, 93.8%, respectively. When we comapre the completely-corrected visual acuity with the visual acuity with dricted axes, the bigger the width of visual acuity's weakness was the bigger the drifted angle. The change of normal visual acuity according to drifting angle of corrected axises of astigmatism, when we compared with full correction, appeared 0.94 in 5 degree, 0.87 in 10 degree, and 0.79 in 15 degree. Drift of 5 degree from fully corrected axis, corresponded to difference of visual acuity about one line, drift of 10 degree to 1.8 line difference of visual acuity, and drift of 15 degree about to 2.6 line difference. Through this study, we were sure that, in the case of drifting away from the right axis of astigmatism, it lead to visual weakness and asthenopia. Therefore we darely advise that optometrists should make mistake of axis least by confirming accucacy of corrected axis after despensing of spectacles of astigmatism.

• Journal of Korean Ophthalmic Optics Society
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• v.21 no.1
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• pp.77-81
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• 2016

Purpose: This study was performed to investigate the difference of meridional visual acuity and the loss of corrected visual acuity (VA) in order to emphasis the importance of astigmatic correction. Methods: 64 subjects (122 eyes) aged $22.75{\pm}2.36years$ participated in this study. After full correction of astigmatic refractive error, VA was measured in which the direction of the slit filter was matched with astigmatic axis and $90^{\circ}$ to the astigmatic axis. Results: 52 eyes showed no difference in VA between the two direction. However 70 eyes had difference VA between them. 14 out of 52 eyes and 24 out of 70 eyes had under 1.0 in monocular VA. The astigmatic degree was higher in the existence of VA difference between the two direction than non-existence. The difference is higher with under 1.0 monocular VA. Monocular VA is closely related to the focal line having better VA in the principal focal line. Glasses replacement period was analyzed as 6~12 months for the preservation of better VA. Conclusions: The final glasses prescription has to be given with full correction because continued under-correction for astigmatism causes meridional VA difference.

• Journal of Korean Ophthalmic Optics Society
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• v.2 no.1
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• pp.149-154
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• 1997

We investigated the dominant eye of 123 Korean over twenty years old, then examined the refractive correlation of dominant eye, the unaided visual acuity and over-correlation. The results of these investigations are following. 91 persons of the whole number, 74%, have the dominant eye of right. The refractive correlation to the glasses are the high dominant eye. There are many men who are the same in unaided visual acuity. In men, they prefer to have the non-dominant eye but in women, they like better to have the dominant eye. The unaided visual acuity of ametropia, however, prefer to have the non-dominant eye in both men and women. In case of over-correction of an eye, there was affected the response of the other eye over 50% at the same time and the case of over-correction of dominant eye has more number than that of non-dominant eye.

• Journal of Korean Ophthalmic Optics Society
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• v.19 no.2
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• pp.207-216
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• 2014

Purpose: In this study, we analyzed visual acuity of children according to the rearing of the type of parents. Methods: We have done a comparative analysis about before and after of corrected visual acuity according to the wearing actual conditions with the Korean National Health and Nutrition Examination Survey 2010 document. Results: Visual acuity before correction of twoparent family's children was 0.91, single parent family's children was 0.83, grandparents family's children was 0.77 in low income and twoparent family's children was 0.80, single parent family's children was 0.77, grandparents family's children was 0.50 in lower middle income. Conclusions: In the rearing of low-income children, the lack of attention to visual acuity management according to the type of parents leads to a failing of visual acuity in myopia. The role of the parents is very important during this time period, so it is necessary to provide social interest giving decline prevention of vision.