• Journal of the Optical Society of Korea
• /
• v.17 no.2
• /
• pp.219-223
• /
• 2013

The purpose of this study was to determine the relationship between the spherical equivalent visual acuity (VA) and uncorrected astigmatism. On 108 emmetropic eyes, the spherical equivalent VA was measured for cross cylindrical lens (CC lens)-induced astigmatic eyes and the VA-astigmatism relation determined. On 158 astigmatic eyes, the spherical equivalent VA and corrected astigmatism were measured and the measured values were compared with the calculated values from the VA-astigmatism relation by correlation coefficient analysis. Subsequent to that, the relationship between spherical equivalent VA and uncorrected astigmatism was made. The relationship was fitted for an exponential equation. Correlation coefficient between calculated values by equation and measured values for astigmatic eyes was 0.991 (p<0.01). The relationship between the spherical equivalent VA and the uncorrected astigmatism was decided as follows (spherical equivalent VA / uncorrected astigmatism): 1.0 / 0.25 D, 0.9 / 0.50 D, 0.8 / 0.75 D, 0.7 / 1.00 D, 0.6 / 1.25 D, 0.5 / 1.50 D, 0.4 / 2.00 D, 0.3 / 2.50 D, 0.2 / 3.00 D, 0.1 / 4.00 D, and 0.05 / 4.75 D. In conclusion, the relationship table devised from this study is a useful reference for predicting uncorrected astigmatism by measurement of decimal VA in spherical equivalent.

• Journal of Korean Ophthalmic Optics Society
• /
• v.16 no.2
• /
• pp.167-170
• /
• 2011

Purpose: This study was tried whether expectation of astigmatism from spherical equivalent visual acuity was possible. Methods: For 54 men and women (108 eyes) corrected to emmetropia, average age of 23.3, changes of visual acuity (5m) were measured with an increasing the powers at every ${\pm}$0.25D when the (-) axis of cross cylinder is $180^{\circ}$, $90^{\circ}$, and $45^{\circ}$, respectively. Results: As the power of cross cylinder was increased, visual acuity was decreased. When the powers of cross cylinder were ${\pm}$2.50D ($180^{\circ}$ and $90^{\circ}$) and ${\pm}$2.25D ($45^{\circ}$), visual acuity was 0.05 which is the minimum measurement possible. Conclusions: The diagram on astigmatism dealing with each spherical equivalent visual acuity was able to tabulate.

• Journal of Korean Ophthalmic Optics Society
• /
• v.14 no.1
• /
• pp.39-45
• /
• 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
• /
• v.13 no.1
• /
• pp.113-117
• /
• 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.

• Journal of Korean Academy of Nursing
• /
• v.35 no.2
• /
• pp.390-398
• /
• 2005

Purpose: This study was aimed at providing basic data for developing a nursing intervention program which enables systematic and correct visual acuity care by discovering out visual acuity conditions, prevalence rate of myopia, and the factors related to myopia with Preschool children. Method: The subjects of this study consisted of 519 children between 3 and 6 years of age from 12 kindergartens in Seoul which were selected through multiple cluster sampling. Myopia was defined as the spherical equivalent (SE) of more than -0.5 diopters (D) in the right eye. The data was analyzed by t-test, 2-test, ANOVA, and logistic regression by using the SAS program. Result: The prevalence rate of myopia was $8.7\%$. the odds ratio of child myopia when one parent had myopia was 2.2 times higher than when neither parent had myopia. The odds ratio of child myopia when reading more than three books per week was 0.27 times higher than reading less than three books. Conclusion: Myopia should be continuously and intensively managed from the age of 3.

• Journal of Korean Clinical Health Science
• /
• v.2 no.3
• /
• pp.203-208
• /
• 2014

Purpose. To analysis the refractive error in 7-9 year-old Korea children. Methods. From July 2013 to June 2014, two hundred eighty two subjects were performed in refraction test using the Auto-Refractometry. Results. The refractive error by spherical equivalent among all subjects was myopia 47.58%, emmetropia 42.35%, astigmatism 32.33%, and hyperopia 8.76%. Myopia was more common in female than males although the difference was not statically significant. The axis of astigmatism was with the rule in 65%, against the rule in 31.5%, and oblique in 3.5% There was a statistical significance between 7 year and 9 year of male in the spherical equivalent power(p=0.010). Also there was a statistical significance between 7 years and 9 years of female in the spherical equivalent power(p=0.036). However, there was not a statistical significance between male and female in spherical equivalent power(p>0.5). Conclusions. In this study, myopia was the most common refractive error. On the other hand, The prevalence of the axis of astigmatism was the with- the- rule. The spherical equivalent of refractive error was similar results between male and female. However The refractive error was different style with aging. these data suggested that the analysis of the refractive error at young children can provide the information of useful diagnosis for the correction of visual acuity.

• Journal of Korean Ophthalmic Optics Society
• /
• v.2 no.1
• /
• pp.61-76
• /
• 1997

In this paper, we found out the objective refractive errors, the full corrective refractive powers, and the prescriptions for 64 males and 36 females aged 18 to 26 years. To increase the unaided visual acuity 0.1 to the aided visual acuity 1.0 with the glasses, we needed the spherical equivalent refractive power of -3.00D for male and -2.91D for female respectively. To increase the unaided visual acuity 0.5 to the aided visual acuity 1.0 with the glasses, we needed the spherical equivalent refractive power of -0.5D for male and -1.38D for female respectively. Comparing unaided visual acuity and corrective refractive power, the more one has refractive error the less one has unaided visual acuity but these are not linear relationships. Comparing objective refractive error figures, full corrective refractive power figures and prescriptions, objective refractive error figures are the hightest, followed by full corrective refractive power figures. Prescriptions compared with the other two are lower. The cylindrical refractive powers are less than -2.50D. In this study, with the rule astigmatism is dominant over against the rule astigmatism and oblique astigmatism. The accommodation measured by push up method is 6.75D~10.04D for male and 7.50D~9.60D for female respectively.

• Journal of Korean Ophthalmic Optics Society
• /
• v.10 no.1
• /
• pp.35-40
• /
• 2005

Subjective and objective visions were measured on young adults(mean 21 yrs, 126 eyes) who were free of any ocular diseases and laser surgery and none wore contact lenses. The aim of this study was to investigate the diurnal variation of vision through subjective and objective measurements. Subjective visual acuity were measured at 5 m three times a day, morning(8:00 AM-10:00 AM), noon(12:00 PM-2:00 PM) and afternoon(4:00 PM-6:00 PM). The instrument used for objective refraction right after visual acuity measurement was Nvision-K 5001(shin-nippon) which unique in being able to disregard subject's accommodation because of its unrestricted viewing conditions. Also, we measured that three times and then calculated the average values. The result showed that an average subjective visual acuity in the morning, noon, afternoon were 0.256(${\pm}0.263$), 0.266(${\pm}0.276$), 0.242(${\pm}0.249$) respectively. Average spherical equivalent power in objective refraction of right eyes showed -3.416 D(${\pm}2.907$), -3.359 D(${\pm}2.735$), -3.297 D(${\pm}2.709$) respectively and dioptric power was decreased from morning to afternoon. Vision changed throughout the day in both subjective and objective measurements nevertheless its variations were statistically insignificant(p<0.05). Therefore it does not seem to matter of time for either visual acuity test or refraction.

• Journal of Korean Ophthalmic Optics Society
• /
• v.5 no.2
• /
• pp.21-25
• /
• 2000

The old age may experienced the visual acuity decrease according to refraction abnormality and they have a inconvenient real life style on viewing condition. So that, This study can provide the accurate information on the treatment of visual acuity of a male old ages by test of eye refraction state. The test was performed the visual acuity test by the object and subject methods.and the subjects was the Korean male over 55 old age. The eye types were 0.8 % positive for emmetropia, 15.2 % for myopia, and 84 % for hyperopia, respectively. The abnormal refraction eyes were 1.3 % positive for simple myopic astigmatism, 13.9 % for compound myopic astigmatism. 3.4 % for simple hyperopia and 3.1 % for simple hyperopic astigmatism, 77.5 % for mixed astigmatism, respectively. The asix of astigmatisms were 62% positive for against-the-rule astigmatism, 6% for with-the rule astigmatism, and 32 % for oblique astigmatism, respectively. On the total myopic spherical power, the $-0.50{\leq}$spheric equivalent <-2.00 diopter was 84.3%, the $-2.00{\leq}$spherical equivalent <-6.00.diopter was 15.7%. On the total hyperopic spherical power, the $+0.50{\leq}$spheric equivalent <+2.00 diopter was 74.2%, the $+2.00{\leq}$spherical equivalent <+6.00 diopter was 24.8%, and anything over the +6.00 diopter was 1%. On the astigmatic power, the $0.5{\leq}$cylinder <1.00 diopter was 54.1%, the $1.00{\leq}$cylinder <2.00 diopter was 32.4%, and anything over the 2.00 cylinder diopter was 13.5%.

• Journal of Korean Clinical Health Science
• /
• v.7 no.2
• /
• pp.1337-1344
• /
• 2019

Purpose. This study was the analyze the refractive status of presbyopia in Korea. Methods. The subjects was from November 2018 to October 2019, two hundred thirty four subjects( 117 male subjects, 117 female subjects; from 40-year old to 88-year old ) were performed in refraction test using the Auto-Refraction(Speed -K model, Japan). The myopia, hyperopia, astigmatism, and anisometropia were defined as spherical equivalent(SE)≤-0.50 diopters, SE ≥+1.00 D, cylinder error ≥0.75 D and SE difference≥1.00 D between binocular eyes, respectively. Results. The refractive status by spherical equivalent among all subjects was myopia 61.43%, astigmatism 86.86%, emmetropia 19.18%, anisometropia 12.07%, and hyperopia 18.54. The prevalence of myopia and astigmatism were much more common in male. However, The hyperopia and astigmatism were much more common in female. The prevalence of spherical equivalent was much common from -0.50 diopter to -5.00 diopter. On the other hand, the prevalence of astigmatism and myopia was much more than hyperopia in all subjects. There was a statistical significance between OD and OS of the female and male in the spherical equivalent power(p<.000). However, there was not statical significant between female and male of OD and OS in the spherical equivalent power(p<.070). On the other hand, The prevalence of againest axis in astigmatism was more common in all subjects. In ADD power for the near vision correction, the female was much more diopter than male. Conclusions. These results suggested that the analysis of the refractive status on the presbyopia in Korea can give the useful diagnosis data for the correction of visual acuity at near distance.