• Journal of Korean Ophthalmic Optics Society
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• v.19 no.1
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• pp.79-85
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• 2014

Purpose: This study investigated accommodative changes by measuring accommodative response, appearing on the normal and convergence insufficiency Group, by using both eyes open-view auto-refractometer (Nvision-K5001, shin-nippon, Japan). Methods: It carried out objective and subjective refractions, targeting 74 college students (54 males and 20 females) aged between 19 and 29 ($21.59{\pm}2.53$), spherical equivalent OD $-2.28{\pm}2.03$ D, OS $-2.18{\pm}2.01$ D, by measuring accommodative responses at full correction and under correction with plus lens +0.25, +0.50, +0.75 arbitrarily added. Results: In the group of normal and convergence insufficiency, the shorter fixation distances were, the greater accommodative lags showed. The group of convergence insufficiency showed the lesser changes of accommodative response than those of normal. But we found that the convergence insufficiency group had a little larger accommodative amplitude in the total fixation distances. The full correction of convergence insufficiency group and the under correction (+0.50 D) of normal were alike in the accommodative responses. We have also investigated that the correlation between accommodative responses and fixation distances was decreased steeply at the excessive low vision correction. Conclusions: Under correction (+0.50 D) in a near distance is expected to avoid unnecessary accommodative responses, make eyes relaxed and comfortable.

• 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.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.17 no.1
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• pp.75-81
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• 2012

Purpose: The study tried to figure out accommodative changes by measuring accommodative response, appearing on the full vision correction and low vision correction, with both eyes open-view auto-refractometer (Nvision-K5001, Shin-nippon, Japan). Methods: It carried out objective and subjective refractions, targeting 79 college students (58 males and 21 females) aged between 20 and 30($21.14{\pm}2.00$), by measuring accommodative changes with fixation distance at 1.0 m for eyesight of 1.0 after full version correction. The distances of 5.0 m, 1.0 m, 0.50 m, 0.33 m and 0.25 m for eyesight of 0.8, 0.7 and 0.6 after low vision correction arbitrarily added plus lens were applied. Results: the shorter measure fixation distances were, the greater changes accommodative response showed a tendency in the state of both full vision correction and low vision correction(0.7). The state of full vision correction showed a greater change of accommodative response than that of low vision correction(0.7). Both right and left eyes showed low accommodative responses in the state of low vision correction(0.7) than that of full vision correction. As a result of analyzing accommodative response at an eyesight of 0.8, 0.7, and 0.6 after low vision correction, the poorer eyesight was the lower accommodative response. Conclusions: Low vision correction from a near distance is expected to avoid unnecessary accommodative response, make eyes relaxed and prevent accommodative function disorder.

• Journal of Korean Ophthalmic Optics Society
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• v.20 no.2
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• pp.157-165
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• 2015

Purpose: To evaluate changes in central and peripheral refraction along the horizontal visual fields in myopic corneal refractive surgery group compared with emmetropes. Methods: One hundred twenty eyes of 60 subjects ($23.56{\pm}2.54$ years, range: 20 to 29) who underwent myopic refractive surgery and 40 eyes of 20 emmetropes ($22.50{\pm}1.74$ years, range: 20 to 25) were enrolled. The central and peripheral refractions were measured along the horizontal meridianat $5^{\circ}$, $10^{\circ}$, $15^{\circ}$, $20^{\circ}$, $25^{\circ}$ in the nasal and temporal areas using an open-field autorefractor. For analysis of post-op group, the group was classified by pre-op spherical equivalents of < -6.00 D and ${\geq}-6.00D$ as two post-op groups. Results: Pre-op spherical equivalent was $-4.56{\pm}0.92D$ (rang: -2.50 to -5.58 D) in post-op group 1, and $-7.09{\pm}0.96D$ (rang: -6.00 to -9.00 D) in post-op group 2. Spherical equivalent (M) in the emmetropes ranged from $-0.20{\pm}0.22D$ at center to $-0.64{\pm}0.83D$ at $25^{\circ}$ in the temporal visual field and to $-0.20{\pm}0.67D$ at $25^{\circ}$ in the nasal visual field; M in post-op group 1 ranged from $-0.16{\pm}0.29D$ at center to $-5.29{\pm}1.82D$ at $25^{\circ}$ in the temporal visual field and to $-4.48{\pm}1.88D$ at $25^{\circ}$ in the nasal visual field; M in post-op group 2 ranged from $-0.20{\pm}0.32D$ at center to $-7.98{\pm}2.08D$ at $25^{\circ}$ in the temporal visual field and to $-7.90{\pm}2.26D$ at $25^{\circ}$ in the nasal visual field. Among the three groups, there was no significant difference in M at central visual field (p=0.600) and at $5^{\circ}$ in the temporal visual field (p=0.647), whereas, there was significant difference in M at paracentral and peripheral visual field (p=0.000). Conclusions: Emmetropes had relatively constant refractive errors throughout the central and peripheral visual field and showed myopic peripheral defocus along the horizontal visual field. On the other hand, in myopic corneal refractive surgery group, there were significant differences in refractive errors between the central and peripheral visual field compared with differences in the central and peripheral refraction patterns of emmetropes.

• Journal of Korean Ophthalmic Optics Society
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• v.6 no.2
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• pp.139-144
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• 2001

This paper was investigated the change of naked visual acuity and the full corrective refractive powers of alcoholicity for 0, 0.05 and 0.1. We research the prescriptions for 9 males and females 9 aged 20 above years. The naked visual acuity was decreased with increasing alcoholicity. Most of tested patients, the spherical refractive powers was also decreased with increasing alcoholicity. The change of the cylinder refractive power was uniformity. For the astigmatism axis. there were many changes.

• Journal of Korean Ophthalmic Optics Society
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• v.5 no.1
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• pp.139-146
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• 2000

Once refractive error of the eye was fully corrected, Maddox rod was used to investigate binocular vision function. When the deviations of subjects' eyes were measured, orthophoria. without any horizontal deviations, was found in 10%, esophoria in 55% and exophoria in 34% of the patients. Esodeviation of the eye was found to be greater than exo-deviation by 11%. This is also refracted in deviations found to be greater than $4{\Delta}$ diopter magnitude where esophoria was 23% and exophoria was 9%. Thus for the patients to achieve comfortable binocular vision function, binocular vision anomalies need to be considered in spectacle prescription. In examining ocular anomalies of corrected refractive error, the deviation of the eye differed from under corrected refractive power to over corrected refractive power. There was a decrease in exophoria and an increase in esophoria, with over correction. This was thought to be due to accommodation. Furthermore, calculated AC/A ratio was found to vary from 1.25 to 6.61 and its relationship to refractive error could not be determined.

• Journal of Korean Ophthalmic Optics Society
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• v.11 no.1
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• pp.35-41
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• 2006

I performed the refraction and binocular test for study of binocular abnormalities. The problems of the accommodation and binocular on subjects was need to the correction of the refractive error. also the subjects was need to a specific treatment for each of the problems. On two patients who had convergence excess, The full corrections of eyeglasses or (+)ADD for near vision were prescribed and the subjects trained for 4 weeks. After 4 weeks, the unconvenience of near vision have more decrease, and the objective test have good results. On clinical, If the optical correction and vision therapy was applied the treatment for binocular abnormalities. The continuous research of vision training in binocular abnormalities will be good results for treatment of several binocular abnormalities in the future.

• Journal of Korean Ophthalmic Optics Society
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• v.20 no.3
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• pp.349-354
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• 2015

Purpose: To investigate the changes of corrective values of astigmatism caused by the position of circle of least confusion on retina in refining astigmatic test using cross cylinder. Methods: 62 subjects (115 eyes) aged $22.24{\pm}2.48$ years participated for this study. After astigmatic test using a radial chart, refining test was performed using a cross cylinder in a condition of maximum plus to maximum visual acuity (MPMVA). Astigmatic refining test was repeatedly performed in each condition of which S+0.75 D, S+0.50 D, S+0.25 D, S-0.25 D, S-0.50 D, and S-0.75 D are added to spherical lenses of MPMVA. The measured values were compared with the values in MPMVA condition. Results: As compared with values in condition of MPMVA, change of astigmatic axis was increased with add the power of (+) spherical lenses and (-) spherical lenses. In same spherical condition, change of astigmatic axis was decreased with increment of astigmatic power (p<0.05). The corrective power of astigmatism was reduced with increment of (+) spherical lenses (p<0.05), and was raised with increment of (-) spherical lenses compared with the power in MPMVA condition. In case of adding (+) spherical lenses, difference of astigmatic power increased with increment of corrective astigmatism power in same test condition. Conclusions: In order to obtain a proper values for corrective astigmatism, position of circle of least confusion should be accurately adjusted before the performing an astigmatism's refining test.

• Journal of Korean Ophthalmic Optics Society
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• v.14 no.4
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• pp.71-75
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• 2009

Purpose: This study was designed to investigate the condition of refractive correction and heterophoria and monocular pupillary distance on myopic elementary school children wearing glasses in Gwangju city. Methods: Subjective refraction and objective refraction were examined after investigating heterophoria and monocular pupillary distance on 145 (290eye) elementary school children wearing myopia-corrected glasses. Results: 1. Anisometropia > 2.00 D was present in 4 children (3%). 2. 9 anisometropia (47%) were present in 19 undercorrected visual acuity boy wearers. and 16 anisometropia (64%) were present in 25 undercorrected visual acuity girl wearers. 3. Among the 67 myopic glasses boy wearers, the distance between optical centers was coincided with the pupillary distance in 30% (Oculus Uterque), and discrepant in 70% (Oculus Uterque). Among the 78 myopic glasses girl wearers, the distance between optical centers was coincided with the pupillary distance in 23% (Oculus Uterque), and discrepant in 77% (Oculus Uterque). The mean optical center distance was longer than the pupillary distance on both boy and girl wearers 4. The result of measured heterophoria revealed 14% for orthophoria, 63% for exophoria, 23% for esophoria at far distance and 10% for orthophoria, 76% for exophoria, 14% for esophoria at near distance. Conclusions: Correct refractive test and monocular pupillary distance must be examined because incorrect refractive test and pupillary distance induce asthenopia and heterophoria.