• Journal of the Korea Convergence Society
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• v.11 no.8
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• pp.317-321
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• 2020

This study researched the correlation between myopic refractive errors and intraocular pressure. The study population comprised 39 adults(17 of males, 22 of females). We measured the intraocular pressure using a Non-Contact Tonometer(NCT) and the correlation between myopic refractive errors was analyzed by dividing into three groups: mild, moderate, high myopia. The gender of subjects showed no statistically difference between the intraocular pressure and refractive errors, but as the refractive errors increased, the intraocular pressure incereased, which showed a statistically significant difference. In addition, the higher intraocular pressure in moderate and high myopia than mild myopia can cause glaucoma, that can develop at a young age. it is need to sufficient recognition and understanding correlation between intraocular pressure and myopic refractive errors in the middle-aged high myopia.

• Journal of Korean Ophthalmic Optics Society
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• v.14 no.4
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• pp.53-57
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• 2009

Purpose: To study the relationship of N.P.C, heterophoria and near convergence and divergence by amount of the refractive error. Methods: All subjects have no ocular disease and their mean age is 22.7. All 39 subjects examined about refractive error, near point of convergence (NPC), heterophoria, near convergence and divergence. Results: Classified by low refractive state, middle refractive state, and high refractive state compared with the expected value of Morgan. NPC had been measured within low and middle refractive state eight all the 8cm. However, high refractive state measured 9.64 cm. Low and middle refractive state for the classification by near phoria. Near esophoria groups was smallest by near divergence and exophoria groups was smallest by near convergence. Conclusions: Near convergence were largest with esophoria while near divergence were largest with exophoria.

• Journal of Korean Ophthalmic Optics Society
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• v.15 no.4
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• pp.389-397
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• 2010

Purpose: This study was to investigate the changes of refractive error and astigmatism associated with age in Korean subjects between the ages of 6 and 80 years during 10-year period. Methods: 220 normal subjects (345 eyes) who visited ophthalmic clinic was recruited and followed for 10 years between 1999 and 2009, cycloplegic manifest refraction being performed annually. Visual acuity was tested on a Han's chart. Results: The mean 10-year change in the spherical equivalent refraction (SER) of age 6 to 10 years old and 10 to 20 years was -3.649D and -2.165D respectively. There was no change of refractive error in age 21 to 40 years. The myopic shift decreased with age from 41 up to 69 years but increased slightly in patients 70 years and older; the hyperopic shift showed the opposite trend. The distribution of refractive error over the 10 years in aged 6 to 10 and 11 to 20 years was shifted myopic. The incidence of medium (> -3.01D) to high myopia at age 6 to 10 years was 4.8% and after 10 years was 62.5%. The 10-year change of astigmatism axis was in "with the rule" direction for younger age group and in a "against the rule" direction for older subjects. Conclusions: This study has documented refractive error changes in Korean subjects and confirmed reported trends of myopic shift from age 6-20 years and hyperopic shift before age 70 years and a myopic shift thereafter. The axis of astigmatism turns to "against the rule" after 40's.

• Journal of Korean Ophthalmic Optics Society
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• v.4 no.2
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• pp.23-31
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• 1999

The purpose of this study is to evaluate the relationship between axial length/corneal radius ratio and refractive error for human eye. Ocular components were measured Baush & Lomb keratometer, Holden-Payor pachometer, and Stoz Compuscan. Refractive error was measured by subjective refraction. The results were as follows; 1) Spherical equivalent refractive error and axial length/corneal radius ratio was very highly correlated with the correlation coefficient for -0.89. 2) Axial length/corneal radius ratio and axial length, vitreous chamber depth were highly correlated that the correlation coefficients were 0.82, 0.80 respectively. 3) Axial length/corneal radius ratio and anterior chamber depth, corneal power, corneal radius, lens power were correlated with the correlation coefficients for 0.57, 0.40, -0.39, -0.35 respectively. 4) There were no significant correlation between axial length/corneal radius ratio and lens thickness, and corneal thickness.

• Journal of Korean Ophthalmic Optics Society
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• v.4 no.1
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• pp.27-35
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• 1999

The corneal power and eye refraction error were studed in 472 unaccommodated right eyes of Korean adult human aged above 20 years. The mean corneal refractive power is 44.08D (female : 44.28D, male : 43.76D). It is 1.1D higher than that of the medel eye by Gullstrand (about 43.0D). The mean corneal power of myopia(44.11D) is similar that of emmetropia(43.97D) and hyperopia(44.24D), but mean corneal power of myopia between the ages of 20 and 29 is 1.42D higher than that of emmetropia. The corneal powers as a function of ages are enlarged with increasing rate of 0.2D~0.3D/10years.

• Journal of Korean Ophthalmic Optics Society
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• v.8 no.1
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• pp.41-45
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• 2003

The researchers have studied on the effect of three main morphological types(nuclear, cortical, and subcapsular cataract) of age related cataract on refractive error. We also identified that spherical and cylinderical shift in each type of morphological cataract accoding to their locations and effect of intraocular pressure before and after cataract surgery. Nuclear cataract showed myopic shift while cortical cataract showed hyperopic shift, and subcapsular cataract showed not significant changes on both direction. Age related cataract subjects(120 eyes) only were recruited from sun-cheon area. We use optic section of slit lamp biomicroscope to identify the anatomical location of cataract, and optimal refractive correction determined by objective(retinoscope) and subjective refraction then spherical changes were calculated from the spherical eqivalent value. Intra-ocular pressure were measured by auto-tonometer before and 7 days after cataract has been replaced by IOL. The change in cylindrical power, usually A-P diameter decreased according to increases of age, A-P diameter increased because intra-ocular pressure rises by progression of cataract and this convertion with the rule astigmatism to against the rule astigmatism and this increases more by intra-ocular pressure.

• Journal of Korean Ophthalmic Optics Society
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• v.6 no.2
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• pp.81-84
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• 2001

This study can provide the accurate information on the treatment of visual acuity of a old ages by test of eye refraction state. The test was performed the visual acuity test by the object methods, and subjects was the over 45 old age. The eye types were 12% positive for emmetropia, 19% for myopia. and 69% for hyperopia, respectively. The abnormal refraction eyes were 3% positive for simple myopic astigmatism, 16% for myopic astigmatism, 14% for simple hyperopia, 5% for simple hyperopic astigmatism, 62% for mixed astigmatism, respectively. The axis of astigmatisms were 72% positive for against-the-rule astigmatism, 21% for with-the-rule astigmatism, 7% for ablique astigmatism, respectively.

• Journal of Korean Ophthalmic Optics Society
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• v.12 no.3
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• pp.1-5
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• 2007

This is a succeeding article of J. Korean Optalmic Optics Society vol. 11(2) pp. 121-129(2006) [Research about the distribution of refractive errors in distinction of gender and at age of Kyonggi province's partial area]. The former article showed age-specific distribution of myopia, hyperopia and astigmatism which generally appears in refractive errors. This paper aimed to investigate the change of refractive power and prevalence of refractive errors by age. Total 928 subjects were sampled and their refractive errors were determined using auto refractometer. As the results, change of refractive power of subjects appeared at the age about 40, and suddenly reduced over 46 years resulting in (+)refractive power at their fifties. Relative risks of refractive errors of myopia increased in younger subjects but the risks decreased in older subjects (over 46 years). On the other hand, the risks of hyperopia decreased as the age of subjects increase, but could increase to 0.24 (95% CI: 0.07-0.88) after 36 years. This results showed that presbyopia might progress more early when people were before 40 years.

• Journal of Korean Ophthalmic Optics Society
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• v.18 no.3
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• pp.271-277
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• 2013

Purpose: The purpose was to study the corneal refractive power changes associated with the wearing of everted silicone hydrogel soft lenses. Methods: The corneal refractive power and corneal astigmatism were measured using corneal topographer (CT-1000, Shin-nippon Co., Japan) for checking change of corneal refractive power and objective refractive error was measured by auto-refractometer (Natural vision-K 5001, Shin-nippon Co., Japan). We measured at baseline and 1 week after lens wearing. Results: The correcting of corneal refractive power could be effective in low myopia. It's more effective to the higher power of greatest meridian of cornea and the more corneal astigmatism. 73% of subjects' refractive error was decrease less than 1 D and 17% of the subjects had an reverse effect (increase) occurs. The reduction of objective refractive error was more effective when cornea refractive power was great or corneal astigmatism was much. Conclusions: Pressure which the everted silicone hydrogel lens to the cornea could be caused. It occurred as the degrees of corneal power, corneal astigmatism and objective refractive error differences. Selection of an appropriate subject is important considering difficulty of changing the parameters of the lens.

• Journal of Korean Ophthalmic Optics Society
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• v.13 no.1
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• pp.89-94
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• 2008

Purpose: To make a comparative study of correlation between biometry data of size in eyeball and refractive error. Methods: The subjects were 68 normal university students (male 36, female 32) and the average age was 22.85${\pm}$3.12. We measured the students' eyesight by A-scan ultrasound and refractor. The results were examined it's statistical significance by SPSS 12.0 version. Results: The mean of axial length was 24.31${\pm}$1.24 mm, chamber depth was 3.48${\pm}$0.28 mm, lens thickness was 3.56${\pm}$0.26 mm and corneal thickness was 0.55${\pm}$0.03 mm. Male's Axial length and chamber depth were larger than female's. As reflective error decreases the thickness of lens become thicker. The measurement data between right eye and left eye didn't had difference and there was no correlation with result of T-test. There were statistically significant correlation with length and chamber depth, axial length and corneal thickness, chamber depth and corneal thickness, and refractive error and lens thickness (p<0.01). Refractive error and axial length were minus linear regression (r=-0.56). Conclusions: Eye's refractive error was changed by axial length, chamber depth and lens thickness but it wasn't related with sex and whether it is a right eye or a left eye.