• Journal of Korean Ophthalmic Optics Society
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• v.18 no.4
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• pp.465-471
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• 2013

Purpose: This study was conducted to research effects of influence factors on stereopsis of induced aniseikonia in emmetropia. Methods: 20 college students (a mean age of $22.50{\pm}2.72$ years, 14 males, 6 females) were selected as subjects and all of them had no ocular disease or systemic disease, the refractive correction of spherical equivalent within ${\pm}0.50$ D, the corrected visual acuity of 1.0 or better and the aniseikonia values less than 1% by AWAYA. Subject's dominant eye was checked by Hole in card method and contact lenses of -7.00 ~ +7.00D were fitted to cause anisometropia in dominant eye or non-dominant eye, respectively. And then aniseikonia was induced with spectacles to correct refractive error by contact lenses. Stereopsis was measured by Random Dot Stereo Acuity Test with LEA symbols$^{(R)}$ (Vision Assessment Corporation$^{TM}$, USA). Results: Stereopsis was remarkably reduced by inducing aniseikonia, with induced aniseikonia in dominant eye, with higher diopter of wearing contact lenses to induce anisometropia, with spectacles lenses correction of minus power after fitting contact lenses with plus power and in case of men. Conclusions: It should be considered to correct anisometropia that aniseikonia could cause reduction of stereopsis.

• Journal of Korean Ophthalmic Optics Society
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• v.17 no.1
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• pp.67-74
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• 2012

Purpose: The purpose of this study to evaluate visual acuity and refractive state and measure and analyze the components of eye's optical system in children and teenagers. Methods: With subjects of 124 (230 eyes) children and teenagers who had no eye diseases, correlation between the correlation between refractive errors and component's of eye's optical system was investigated. The spherical equivalent power of cycloplegic clinical refraction or manifest clinical refraction(SE), corneal power(CP), corneal radius(CR), axial length(AL), anterior chamber depth(ACD) and axial length to corneal radius (AL/CR) ratio were measured and analysed. Results: the SE was negatively correlated with the AL(r = -0.80, p = 0.00), the ACD(r = -0.35, p = 0.00) and the CR(r = -0.11, p=0.00) and positively correlated with the CP(r = +0.11, p=0.00). The AL was positively correlated with the AL/CR ratio (r = +0.84, p = 0.00), the ACD(r = +0.47, p=0.00) and the CR(r = +0.38, p = 0.00) and negatively correlated with the CP(r = -0.38, p=0.00). The CR was negatively correlated with CP(r = -1.00, p = 0.00), the AL/CR ratio(r = -0.19, p = 0.00) and the ACD(r = -0.06, p = 0.39). The CP was positively correlated with the AL/CR ratio(r = +0.19, p = 0.00) and the ACD(r = +0.06, p = 0.39). The ACD was positively correlated with the AL/CR ratio(r = 0.53, p = 0.00). Conclusions: the highest change of refractive errors was shown that the AL/CR ratio was a very important indicator for diagnosing the refractive errors of the children and teenagers.

• Journal of Korean Ophthalmic Optics Society
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• v.2 no.1
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• pp.133-143
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• 1997

A population-based study of people aged above 20 years showed that 32% had emmetropia and 68% had ammetropia(myopia 56.6%. hyperopia 11.4%) city in Korea. The percentage of ammetropia in population based study is higher than that of clinic(O.P.D.) based. A 83.3% of the ammetropia had myopia. which is higher than 76.3% of 1968 and 76.9% of 1975 years. A 16.7% of the ammetropia had hyperopia. which is lower than 19.4% of 1968 and 17.3% of 1975 years. In the kind of refractive error. 32.1% of 985 eyes examined had compound myopic astigmatism. 18.2% had simple myopic astigmatism. 14.2% had simple myopia. 6.8% had simple hyperopic astigmatism, 5.0% had mixed astigmatism, 4.7% had compound hyperopic astigmatism and 3.6% had simple hyperopia. In the difference of binocular refractive error, 29% had 0.50~2.00 Dptr difference and 3.6% had difference above 2.00 Dptr. In age related myopic refractive error, 76.7% of people aged 20~29 years and 74.0% of 30~39 years had myopia. It is due to overstudy for entrance into a university that the percentage of myopia is higher than that of abroad. In age related hyperopic refractive error, 2.9% of people aged 20~29 years, 0.6% of 30~39 years. 6.3% of 40~49 years, 16.0% of 50~59 years and 63.9% of 60~69 years had hyperopia. It shows that the age related hyperopic refractive error was significantly increased at aged 40~49 years. The right eye had more myopic refractive error than left eye.

• Journal of Korean Ophthalmic Optics Society
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• v.15 no.2
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• pp.145-150
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• 2010

Purpose: In this study we investigated the correlation between the effect of myopia correction and the change of corneal eccentricity using reverse geometry lens. Methods: The 23 students (46 eyes) continuously wearing reverse geometry lens during 3 months were divided into Group I and Group II by different parameter fitting methods of wearing Reverse Geometry Lens. We measured a corneal eccentricity for Group I and Group II at $10^{\circ}$, $20^{\circ}$, and $30^{\circ}$ positions from corneal apex before wearing reverse geometry lens, 1 week, 1 month, and 3 months after wearing reverse geometry lens. We also measured an uncorrected visual acuity, a spherical equivalent, and a corneal radius and analyzed the correlation between them and the change of corneal eccentricity using statistical significance test. Results: There were the statistical significances of a change of corneal eccentricity (p=0.03, t=-2.29) for Group I and Group II at 10 position from corneal apex in a week after wearing reverse geometry lens, but were not those (p>0.05) in 1 month, and 3 months after wearing reverse geometry lens. There were the statistical significances of correlation between the change of corneal eccentricity and a corrected visual acuity, and a corneal radius, respectively. Particularly, the high correlation between the change of corneal eccentricity and a corrected visual acuity (r=-0.36, p=0.00, t=6.5), and a spherical equivalent (r=-0.72, p=0.00, t=-70.5) for Group II in a week after wearing reverse geometry lens showed. Conclusions: We knew from these results that the high correlation between the effect of myopia correction and the change of corneal eccentricity in a week after wearing reverse geometry lens represented.

• 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.15 no.2
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• pp.175-183
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• 2010

Purpose: This study investigated the impact of ametropia and myopia on health-related quality of life (QoL) measures in elementary schoolers. Methods: Elementary school children of 92 aged 12 to 13 were divided into emmetropia and myopia groups by spherical equivalent. Then myopia was classified into the low, moderate and high myopia groups. Vision-related QoL scores were determined using PedsQL 4.0 (Pediatric Quality of Life Inventory) with physical health (8 items), emotional functioning (4 items), social functioning (5 items) and school functioning (5 items). Results: The total QoL score in the myopia group appeared lower than that in the emmetropia group, however the difference was not statistically significant (p>0.05). When it comes to physical health (running or exercising) and social functioning (getting along with friends or being teased)-related questions, the QoL score in myopia was low compared with the emmetropia group (p<0.05). High myopia showed a low score in physical health items but there was no significant difference in overall QoL scores in comparison with other groups (p<0.05). Conclusions: Refractive errors does not have a great impact on the total health-related QoL in elementary school children but it causes discomfort in physical health and social functioning.

• Journal of Korean Ophthalmic Optics Society
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• v.17 no.1
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• pp.19-26
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• 2012

Purpose: This paper was to study the clinical effects of moderating myopia by comparing the myopia control lens, which was being recently recognized as a method of inhibiting the progression of myopia, with the wearers of single vision lens. Methods: Using 56 subjects between the ages of 8-15 years (112 eyes) with myopia in the areas of City of Daegu and Gyeongsangbuk Province as study subjects, refractive error, axial length, near point of convergence and accommodative near point were measured and compared a total of 3 times at the baseline, after 1-month and after 6-months. Results: For refractive error, suppression and mitigation were seen in the progression of spherical equivalent when MC lens was worn, as compared to using SV lens, and, when axial length MC lens was worn, the axial progression was significantly suppressed and delayed (p < 0.05). The near point of convergence became shorter with the use of MC lens, and the amplitude of convergence was improved when MC lens was worn. Accommodative near point became shorter with the use of MC lens, and focus ability was significantly improved (p <0.05). Conclusions: It was shown that MC lens, compared to SV lens, could alleviate myopia progression in school-age children and youth. It is considered that MC lens can be used as a useful therapy for the inhibition of myopia progression in the increasing number of myopic children and adolescents.

• Journal of Korean Ophthalmic Optics Society
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• v.8 no.1
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• pp.29-33
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• 2003

There are reports that the myopia progression have been difference according to myopia degree and age. In this studies, we divided into three investigated groups. The A group is the lower elementary school(50), the B group is the high elementary school(50), the C group is the junior high school(50) and the D group is the high school students(50). The myopia progression have been compared with each group and most variable terms have been investigated. We have analyzed the refraction inspection record that were investigated to put on spectacles in three years(visiting three times or more). The subject of study were 200 persons(men 100, women 100), 1. The distribution of equivalence with ages : A group -2.72D, B group -2.90D, C group -3.53D, D group -3.96D. 2. The pupillary distance have been 57.4mm(A), 59.9mm(B), 61.6mm(C), 63.4mm(D). 3. On a monthly variation : -0.02D(A), -0.045(B), -0.050D(C), -0.025(D) in men, and -0.06D(A), -0.06D(B), -0.045(C), -0.04D(D) in women. 4. After due considering monthly variation and suppose that the variatting times of spectacles degress were time of refracting inspection. The result : 3.6 month for A group, 4.8 month for B group, 5.3 month for C group and 7.7 month for D group.

• Journal of Korean Ophthalmic Optics Society
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• v.16 no.2
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• pp.195-200
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• 2011

Purpose: We analyzed the influence of myopic's eye-glasses wearing on myopia progress after cycloplegic refraction. Methods: The 33 people (66 eyes) were school children from 8 years to 12 years having no experience eye-glasses wearing, they were taken cycloplegic refraction at the 100th, the 200th and 300th days in order to evaluate myopia progression. We investigated the eye-glasses wearing group (experimental group, 32 eyes) and the non-eye-glasses wearing group (control group, 34 eyes). The eye-glasses power of the experimental group were -0.50 D, -0.75 D, -1.00 D, -1.25 D and -1.50 D. We compared experimental group with control group for myopia progress according to period, age, and refraction error and investigated the myopia progress according to the eye-glasses power of experimental group. Results: At the 300th day from the first cycloplegic refaction, spherical equivalent for the experimental group increased as -1.03${\pm}$0.43 D (t=13.36, p<0.001) and for the control group increase as -0.61${\pm}$0.35 D (t=10.05, p<0.001) and two groups were statistical difference. Myopia power for experimental group increased 60.75%, for control group increased 56.66% at the 300 days. According to eye-glasses power increased 41.19${\pm}$15.25% at -1.50 D, 36.74${\pm}$19.29% at -1.25 D, 56.57${\pm}$20.21% at -1.00 D, 87.26${\pm}$49.38% at -0.75 D and 106.69${\pm}$59.60% at -0.50 D. Conclusions: The myopia power for the eye-glasses wearing group was 0.46 D faster than the non-eye-glasses wearing group at the 300th day from the first cycloplegic refraction. We will consider the effect of non-eye-glasses wearing to protect the progressing myopia and prescribe the under correction for school children having no experience eye-glasses wearing.

• The Korean Journal of Vision Science
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• v.20 no.4
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• pp.543-551
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• 2018

Purpose : The purposes of this study were to evaluate the changes of intraocular pressure according to corneal ablation amount after corneal refractive surgery and the changes of intraocular pressure according to refractive errors before corneal refractive surgery. Methods : The mean age of adults who underwent LASIK corneal refractive surgery were $37.34{\pm}7.42years$, and 108 adults(48 males, 60 females) were participated in this study. Refractive errors, intraocular pressure, and corneal ablation amount were measured using an autorefractor, a noncontact tonometer, and an excimer laser. All test values were considered statistically significant when p<0.05. Results : The mean intraocular pressure before corneal refractive surgery was $15.08{\pm}2.60mmHg$ in males and $14.16{\pm}2.67mmHg$ in females. The decrease of intraocular pressure after corneal refractive surgery were 4.22mmHg in males and 3.61mmHg in females. Spherical equivalent power were $-3.89{\pm}2.17D$ in males and $-4.45{\pm}2.92D$ in females before corneal refractive surgery, and $-0.10{\pm}0.46D$ in males and $-0.04{\pm}0.46D$ in females after corneal refractive surgery. The corneal ablation amount after corneal refractive surgery were statistically significant, with $53.95{\mu}m$ in males and $61.26{\mu}m$ in females. There was significant correlation between corneal ablation amount and decrease of intaocluar pressure(r=0.2299, p<0.001). As the growth of corneal ablation amount in males, the decrease of intraocular pressure was significantly increased. As the growth of refractive error, the amount of decrease in intraocular pressure was also significant. The decrease of intraocualr pressure were $3.04{\pm}2.18mmHg$ in low refractive error, $4.10{\pm}2.16mmHg$ in middle refractive error, and $4.65{\pm}3.29mmHg$ in high refractive error. Conclusion : We found that intraocular pressure decreased after corneal refractive surgery by noncontact tonometer and the change of intraocular pressure which is an important index for glaucoma diagnosis, may affect the judgment of eye disease. We think that a preliminary questionnaire whether corneal refractive surgery is necessary for the measurement of intraocular pressure.