• Journal of Korean Ophthalmic Optics Society
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• v.16 no.1
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• pp.41-50
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• 2011

Purpose: The present study was conducted to compare the centration of RGP lens on cornea when lens was fitted based on keratometric astigmatisms measured by keratometer and the lens centration when fitted by corneal topography. Methods: Thirty eight eyes of 19 male and female in their twenties were applied RGP lens with 9.9 mm of diameter by the keratometric astigmatisms classified by the measurement with a keratometer. Then, lens centrations were estimated using high speed camera and compared with the lens centration when fitted by total keratometric astigmatism using corneal topography. The relationship of the steepest location of cornea and lens centration was further compared. Results: With the rule astigmatism, lens centration was not changed even with the difference in central and total keratometric astigmatisms. When the relationship of the steepest part of cornea measured by corneal topography and lens centration was analyzed, the lens centration in vertical direction was exactly correlated with the steepest part of cornea in 52.3% of subjects. In the case of non-correlation, the steepest part of cornea was mostly upper part of cornea, however, lens centration was located on lower part of cornea. The lens centration in horizontal direction was exactly correlated with the steepest region of cornea in 65.6% of subjects. In non-correlated case, the difference in cornea curvatures between the steepest and the flattest parts was smaller than 0.05 mm in 76.9% of subjects. Conclusions: From these results, we conclude that corneal topographic patterns may more contribute the centration of RGP lens on cornea than the difference in central and total keratometric astigmatisms.

• Journal of Korean Ophthalmic Optics Society
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• v.10 no.4
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• pp.323-328
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• 2005

The purpose of this research was to measurement real Accommodative response amount using both eyes open-view autorefractometer. Compared each Accommodative response amount to distinction of sex, age, kind of ametropia, amount of astigmatism and kind of astigmatism. The subjects were 153 healthy men and women between the age of 20~80 years. Age comparison, 20 years 1.15D, 30 years 1.23D and above 40 years 0.60D. It was no difference between 20 to 30 years old. But, is decrescent remarkably above 40 years old. Ametropia examined by hypermetropia 1.78D, emmetropia 1.51D, low myopia 1.08D, middle myopia 0.72D, high myopia 0.643D. Myopia increased, Accommodative response amount was expose that decrease. Astigmatism examined by non astigmatism 1.13D, low astigmatism 1.12D, middle astigmatism 0.85D, high astigmatism 0.83D. Astigmatism increased, Accommodative response amount was expose that decrease. The sex and astigmatism type difference appeared with the fact that the result is not a difference.

• Journal of Korean Ophthalmic Optics Society
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• v.13 no.1
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• pp.125-129
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• 2008

Purpose: To research the study of abnormal refraction eye on women population of university students in South - East Korea. Methods: Between March 2007 and October 2007, the refraction test of eye glasses wearer was evaluated on women population (367 students, aged 19~22 years) of university in living on Kyung-Nam and Pusan province. Data was analysed with T-test. Results: On the abnormal refraction status, Compound Myopic Astigmatism was 76.72%, simple myopia was 10.90%, mixed astigmatism was 6.27%, respectively. On the prevalence of myopic power, low was 59.57%, moderate was 24.93%, high was 15.49%, respectively. On the myopic equivalent power, the right eye had more increase to compare to left eye. but these was not a statically significant correlation (p<0.5) between the right and left eyes. On the anisometropia of spherical equivalents and cylinder power, most subjects was under 1.0 diopter. On the other hand, the type of astigmatic axis was with-the rule (70.79%), against -the rule (18.41%), and oblique (10.80%). Conclusions: This study identify that the refraction status of abnormal refraction eye on women population in university students in South-East Korea have been more increased prevalence the myopia and astigmatism.

• 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.6 no.1
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• pp.49-53
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• 2001

To investigate the visual acuity of the primary school children. the visual acuity test wan performed the object and subject method. The results were follows. 1. The eye types were 94.8% positive for myopia, 1.2% for emmetropia and 4.0% hyperopia, respectively. 2. The abnormal refraction eyes were 71.3% positive for simple myopia, 17.9% for myopic compound astigmatism, 6.9% for myopic simple astigmatism, and 2.5% for simple hyperopia, 0.6%for hyperopic compound astigmatism, 0.8%for hyperopic simple astigmatism, respectively. 3. The axis of astigmatism were 72.8% for astigmatism with-the-rule, 23.2% for astigmatism against-the-rule, 4.0% for astigmatism oblique, respectively. 4. On the total myopic spheric power, the -0.50

• Journal of Korean Ophthalmic Optics Society
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• v.5 no.2
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• pp.99-105
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• 2000

The classifying distribution by the action style was opticion 100, photoartist 100, college student 100 for the simple myopic 35%, for the simple myopic astigmatism 2%, for the compound myopic astigmatism 30.6% for the mixed astigmatism 62.6% for the compound hyperopic astigmatism 37.4% for the ratio of emmetropia 22.4% respectively. The retractive erroreye were -0.50~-2.00Dptr for the simple myopia 14%, -2.00~-6.00Dptr 16%, -6.00Dptr 5%, C-0.25(90.180)~C-2.00DptrAxis(90, 180) 2% for the simple myopicastigmatismS-0.25C-0.25DptrAxis(90, 180)~S-1.00C-1.00DptrAxis (90, 180) 22.6%, S-1.00C-1.00 DptrAxis (90, 180)~S-2.00C-2.00DptrAxis(90, 180) 8% for the compound myopic astigmatism. S+0.25C -0.25DptrAxis(90, 180)~S+2.00C-2.00DptrAxis(90,180) 6.2% for the mixed astigmatism. S+0.25C+0.25DptrAxis(90,180)~S+1.00C+1.00DptrAxis(90,180) 3.4%, S+1.00C+1.00DptrAxis(90,180)~S+2.00C+2.00DptrAxis(90,180) 0.34% for the compound hyperopic astigmatism.

• Journal of Korean Ophthalmic Optics Society
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• v.14 no.1
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• pp.39-45
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• 2009

Purpose: The purpose of this study is to compare the visual performance by contrast sensitivity (CS) and disability glare (DG) in low astigmatic eyes corrected with toric soft lenses and other optical corrections. Methods: Twenty university students with myopia (-1.00 to -6.50D Sph. with astigmatism up to 1.50 cyl) were enrolled and corrected by five different methods: 1) soft toric lenses; 2) spherical soft contact lenses; 3) RGP lenses; 4) best spectacle corrected visual acuity; 5) spherical equivalent spectacles. All subjects had corrected vision acuity of 20/20 or better. Contrast sensitivity and disability glare were measured using the OPTEC 6500 contrast sensitivity view-in tester included the EyeView Functional Vision Analysis software at photopic or mesopic conditions with glare. Results: At photopic condition, best corrected spectacle wearers had the highest monocular contrast sensitivity at all spatial frequency followed by soft toric lenses, RGP lenses, spherical equivalent spectacles, and spherical soft contact lenses. However, all of them were in normal contrast sensitivity value at photopic condition. At mesopic condition with glare, toric soft lenses were the highest and followed by RGP lenses, spherical equivalent spectacles, best spectacle corrected visual acuity and spherical soft contact lenses. It was observed that spherical soft contact lens wearers demonstrated lower range than normal contrast sensitivity value at mesopic condition with glare. Conclusion: Toric soft lenses gave better visual performance than spherical soft lenses in low astigmatic eyes. Subjects requiring the use of contact lenses under mesophic conditions could benefit from toric soft lenses.

• Journal of Korean Ophthalmic Optics Society
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• v.17 no.4
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• pp.477-482
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• 2012

Purpose: This study is aimed at finding the conditions of ametropia of adults in the Philippines and the South Korean. Methods: The study objects were 7,695(15,390 eyes) Koreans and 2,256(4,512 eyes) Philippines who visited optic clinics and took refraction test. The distributions of their hypermetropias and myopias about astigmatisms were examined, using the method of equivalent spherical power. When astigmatisms were marked in S-C, cylinder lens diopter and astigmatism axis, presbyopic additions and pupillary distances were analyzed by comparison respectively. Results: Among ametropias of Koreans myopias and hypermetropias were 93.69% and 6.31% respectively and about ametropias of Philippines myopia and hypermetropias were 73.43% and 26.57% respectively. As for spherical equivalent power about Koreans, the results showed that Koreans marked -3.352 D about myopia and Philippines marked -2.213 D about it. There is a gap of -1.139 D between them. About hypermetropia Koreans marked 1.147 D and Philippines, 1.251 D and their gap is 0.104 D. As for ametropia of Koreans there is 49.86% in middle myopia, 32.28% about low myopia, 11.55% about high myopia, and 5.54% about low hypermetropia, 0.75% about middle hypermetropia. As for it about Philippines there is 44.53% in low myopia, 25.11% about middle myopia, 3.79% high myopia and 23.03% low hypermetropia, and 3.51% low hypermetropia respectively. As for cylinder lens there is differences of 0.194 D and 0.22 D between Korean and Philippine for both sexes. Totally Koreans have higher cylinders of 0.175 D than Philippines. As for astigmatism, Koreans have direct astigmatism, inverse astigmatism, and oblique astigmatism in their suffering sequence. As for Philippines, they have direct astigmatism, inverse stigmatism, and oblique astigmatism in their abnormal sequence, and they have higher oblique stigmatism than Koreans. As for presbyopic addition, Philippines have higher distributions than Koreans, and 0.296 D is higher in average. As for pupillary distance, Koreans have longer distance of 0.97 mm in man and 0.63 mm in women than Philippines. Conclusions: As for ametropia, Koreans and Philippines have more myopias than hypermetropias, but Philippines have more rates of hypermetropias than Koreans. And Philippines have more presbyopic additions. Koreans have higher morbidity of inverse astigmatism, and Philippines have higher morbidity of oblique astigmatism comparatively. As for pupillary distance, Koreans have longer length in the body characteristics. This shows that geographical circumstances have much to do with refraction conditions of eyes.

• Journal of Korean Ophthalmic Optics Society
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• v.9 no.2
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• pp.323-332
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• 2004

This study researched the visual acuity test object and Auto-refractormeter, visual of near power. The object were composed of middle aged, the old men and women who in habit Daegu. The results were as follows : 1. The subjects consisted of 537 people, 29.98% men, 70.02% women. 2. The emmetropia was 1.12% for myopia, 2.79% for hyperopia, 96.09% for astigmatism. 3. The abnormal refraction was composition for myopic compound astigmatism(16.57%), hyperopia compound astigmatism(45.62%), Mixed astigmatism(33.89%). 4. On the Myopic Spherical Equivalent(S.E) power, the range of -0.50D ${\leq}$ M.S.E < -1.00D was 21.67%, -1.00D ${\leq}$ M.S.E < -2.00D was 48.89%, -2.00D ${\leq}$ M.S.E < -6.00D was 29.44%. 5. On the Hyperopic Spherical Equivalent(S.E) power, the range of +0.50D ${\leq}$ H.S.E < +1.00D was 28.57%, +1.00D ${\leq}$ H.S.E < +2.00D was 49.30%, +2.00D ${\leq}$ H.S.E < +6.00D was 23.13%. 6. The addition power was 1.00D(8.01%), 1.50D(8.57%), 2.00D(13.78%), 2.50D(16.57%), 3.00D(16.95%), 3.50D(17.88%), 4.00D(18.25%).

• Journal of Korean Ophthalmic Optics Society
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• v.13 no.1
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• pp.113-117
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• 2008

Purpose: This study is to survey that uncomfortable feeling of visual acuity in the first wearing glasses, the number of visiting in age, above vision ranging and refractive errors, astigmatism, and anisometropia. Methods: Automatic refraction and naked visual acuity test executed to receive prescription glasses that the man 509 and women's 499 people visited for the first time, among 3~15 years old who visited an ophthalmoiogical hospital, from January to December, 2003. Results: The first wearing glasses started 3 years old and the most cases was 8~9 years old when they were visited visual acuity 0.5 to 0.7 in most cases. Refractive errors appeared 8 years old and its most plentifully with 20.4%, 92.2% was myopia and 5.2% was hyperopia for the man. Also cases of women was 91.9% for myopia and 5.1% for the hyperopia. Spherical equivalent power was S-1.50${\pm}$1.10D and appeared 62.3% for the low myopia. Astigmatism was appeared 44.6% for the with the rule astigmatism and 75% was cylinder power lower than 1.00D. Cases of simple astigmatism need to glass when was cylinder power C-1.37${\pm}$1.01D, and C-0.50D appeared most distribution. More than 2.00D anisometropia appeared 2.3% for the whole subjective. Conclusions: Of the first wearing glasses visual acuity is 0.5~0.7, spherical equivalent power is S-1.50${\pm}$1.10D, cylinder power of simple astigmatism is C-1.37${\pm}$1.01D.