• Journal of Korean Ophthalmic Optics Society
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• v.11 no.4
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• pp.329-335
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• 2006

The aim of this study was to evaluate the relation between Asthenopia of near lateral phoria and fusional reserve and also to provide fundamental clinical data. A total of 97 subjects, aged between 17 and 35 years old, who had no strabismus, an eye trouble or whole body disease, were examined nacked visual acuity, corrected visual acuity, corrected diopter, phoria, fusional reserve tests from October of 2005 to July of 2006. We excluded 8 subjects for the following reasons: if they had an amblyopia affecting binocular vision or inaccurate data. After these exclusions, 87 subjects remained. The results were as follow. According to interview results was that in near works, exophoria and esophoria with asthenopia was 59.6%, 64.7%, and 52.6% respectively. The subjects who have exophoria of $0-6{\Delta}$ in the range of normal state was 19.1%. The subjects who have exophoria of $7{\Delta}$ over in the range of abnormal state was 80.9%. The fusional reserve was in inverse proportion to phoria. The fusional reserve was twice over of phoria were 30.3%, and twice under were 69.7%. The asthenopia complain persons were 33.9% with the twice over fusional reserve of phoria. The asthenopia no complain persons were 66.1% with the twice under fusional reserve of phoria. In conclusion, our research has shown conclusively that there is a link between asthenopia of lateral phoria and fusional reserve and we also find that fusional reserve must be examined when we prescribe for a patient who has phoria.

• Journal of Korean Ophthalmic Optics Society
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• v.16 no.2
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• pp.167-170
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• 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
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• v.6 no.2
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• pp.155-160
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• 2001

To investigate the subjective refractive error with Von Graefe test. Maddox Rod test and polarizing lens test of Horizontal Heterophoria Measurement at distance on normal 109 subjects aged from 18 to 30 years old. The results were as follows: 1. Using Von Graefe Horizontal Heterophoria Measurement, they were measured 15% for orthophoria, 65% for exophoria and 20% for esophoria at distance. 2. Using Maddox Rod Horizontal Heterophoria Measurement, they were measured 14% for orthophoria, 57% for exophoria and 29% for esophoria at distance. 3. Using polarizing lens test of Horizontal Heterophoria Measurement, they were measured 15% for orthophoria, 72% for exophoria and 13% for esophoria at distance. 4. Each test average were $1.32{\Delta}BI$ for Von Graefe test, $0.88{\Delta}BI$ for Maddox Rod test and $1.76{\Delta}BI$ for polarizing lens test. 5. Patient's preference distribution were 44% for Von Graefe test, 28% for Maddox Rod test and 28% for polarizing lens test.

• Journal of Korean Ophthalmic Optics Society
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• v.14 no.4
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• pp.77-81
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• 2009

Purpose: To study the change of fixation disparity and accommodation as fusion contrast is deteriorated. Methods: 16 subjects who had above 20/20 and stereopsis took part. Monocular and binocular refraction were done with Zeiss Polatest Classic whereas the critical angle for stereopsis was done with TNO. A computer programmed with Random-Dot stereogram and vernier test managed a precise change of the fusion contrast and exposure time. Results: The fixation disparity was influenced by reduction of fusion contrast and had tendancy to exophoria (p=0.0004), especially it is considerably higher when uncrossed disparity was shown to exophoric subjects. Although accommodation was not influenced by a change of fusion contrast (p=0.803), vernier acuity was influenced (p=0.0000). Conclusions: Exophoric trend arose as the fusion contrast was reduced, nevertheless there was no accommadative change.

• Journal of Digital Convergence
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• v.10 no.11
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• pp.485-491
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• 2012

To investigate the difference in the value of horizontal heterophoria measured in phoria test of about normal 72 college students, using both Von Graefe test and Maddox rod test. We used two different methods which are Von Graefe test and Maddox rod test on full correction condition at the long distance. Using Von Graefe test of horizontal heterophoria Measurement, We measured 21 patients(29%) for orthophoria, 36 patients(50%) for exophoria and 15 patients(21%) for esophoria at distance. Using Maddox rod test of horizontal heterophoria Measurement, We measured 36 patients(50%) for orthophoria, 26 patients(36%) for exophoria and 10 patients(14%) for esophoria at distance. Each test average were $0.93{\Delta}$ BI for Von Graefe test, $0.96{\Delta}$ BI for Maddox rod test. We could not find the definite difference about the value of horizontal heterophoria aby testing method. Furthermore, heterphoria AC/A ratio was found to vary from 1.0 to 8.8 and its relationship to refractive error could not be determined.

• Journal of Digital Convergence
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• v.10 no.11
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• pp.535-540
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• 2012

This study is to research the differences of tear film for young people in of a day in a restricted indoor space. The subjects are 58 eyes volunteers for twice preliminary inspection and tear test of a day. 58 healthy individuals with no eye disease, no body disease, orthophoria, corrective visual acuity more than 0.8, binocular spherical equivalence difference over 0.50 diopter, the flattest corneal curvature in horizontal meridian and the steepest corneal curvature in vertical meridian were tested. The uncorrective visual acuity, refractive error, corneal curvature, schirmer test and tear break up test were performed in the morning and afternoon. Schirmer test were $16.0{\pm}7.0mm$ in the morning and $14.1{\pm}7.1mm$ in the afternoon. TBUT were $11.3{\pm}0.6$ sec in the morning and $12.1{\pm}0.9$ sec in the afternoon. They have no significant differences.

• Journal of Korean Ophthalmic Optics Society
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• v.5 no.2
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• pp.73-78
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• 2000

The purpose of our study was investigation for the status of eye health in Taejon area. I chose the age of eight to under eighteen 61 institutional care children, and I examed the first visual acuity examination ophthalmoscopy and non-criterion interview. Among 61 institutional care children (primary school student 40.98%, secondary school student 59.01%), 56.74% children were emmetropia, 44.46% were ametropia. Unaided visual acuity 0.7, 0.8 were 37.03% of these children. As refractive errors, 31.14% were myopia. 26.23% were compound myopic astigmatism and only 1.64% institutional care children wearing the glasses. In children, early eye examination is essential for their eye health. Therefore attention to early eye examination and wearing correct glasses seem to be very important especially for institutional care children. I propose that we have to concerned about eye health and concrete plan for institutional care children.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.8 no.2
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• pp.193-204
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• 1998

The single crystal of the $LiTaO_3$has large electro-optic effects, so it is applied to optical switch, acousto-optic deflector, and optical memory device as hologram using photorefractive effect. In this study, optic-grade undoped $LiTaO_3$and Fe:LiTaO$LiTaO_3$single crystals were grown by the Czochralski method and optical transmission and absorption spectrums were measured in the wavelength of UV-VIS range. The curie temperature was determined with DSC and by measuring capacitance for the grown undoped crystal and ceramic powder samples of various Li/Ta ratio. In case of having a 48.6 mol% $Li_2O$ as a starting Li/Ta ratio, the results of concentration variations were below 0.01 mol% $Li_2O$ all over the crystal, so it was confirmed that $LiTaO_3$single crystals were grown under congruent melting composition having optical homogeneity. The curie temperature of the Fe:$LiTaO_3$crystal was increased with increased with increased doped Fe concentrations;by the ratio of $7.5^{\circ}C$ increase per Fe 0.1 wt%. Also, the optical transmittance was about 78 %, which was sufficient for optical device.

• Journal of Korean Ophthalmic Optics Society
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• v.16 no.3
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• pp.229-235
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• 2011

Purpose: The present study was performed to evaluate the safety of ophthalmic lenses in domestic market since eyeglasses wearers could be exposed to the negligent accident by damaged ophthalmic lenses. Method: Totally, 160 ophthalmic lenses (NK55, ${n_{d}}$ = 1.56) with the refractive powers of -3D, -6D, +3D, +6D manufactured by 4 companies in domestic market were evaluated using drop ball test. In accordance with FDA standard, steel ball (~16 g) was freely dropped on these ophthalmic lenses from 127 cm high and the surfaces of lenses were observed. Results: From the study, center thicknesses of NK55 ophthalmic lenses manufactured by 4 different companies showed somewhat different numbers even though the lenses had the same refractive index and powers. All convex lenses of +3D, +6D were evaluated as the safe lenses since there was no damage such as crack and broken found on the lens surfaces after drop ball testing. However, some noticeable broken was shown on the surfaces of concave lenses with relatively thinner center thickness. Especially, 59(73.8%) of total 80 concave lenses with the refractive power of -3D and -6D classified as unacceptable lenses to FDA standard. Conclusions: From the results, the negligent accident by damaged ophthalmic lenses should be considered as well as the correction of visual acuity, design and price when customers purchase eyeglasses. Thus, the enforcement regulation like drop ball testing of uncut ophthalmic lens could be suggested to guarantee the safety of ophthalmic lenses in domestic market.

• Journal of Korean Ophthalmic Optics Society
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• v.21 no.1
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• pp.53-59
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• 2016

Purpose: To investigate an individual phoria compensating effect by measuring the lens adaptation after wearing horizontal prism or spherical lenses at near. Methods: 103 subjects (63 males and 40 females) aged $22.43{\pm}2.07years$ participated for this study. Refractive errors of subjects were fully corrected, and subjects were classified into three groups; esophoria, orthophoria and exophoria. The adaptation test of prism and spherical lenses was performed immediately, 15 minutes and 30 minutes after wearing lenses with $OU\;2\;{\Delta}\;BO$ and S+1.00 D for an esophoria group and $OU\;2\;{\Delta}\;BI$ and S-1.00 D for orthophoria and exophoria groups, respectively. Each measured phoria was compared to phoria measured with fully corrected condition, and the phoria changing effects about both lenses was analyzed. Results: The mean of phoria by prism lenses significantly decreased for every group. The mean of phoria by spherical lenses also significantly decreased in orthophoria and exophoria groups. The esophoria group showed a decreasing tendency but has no significance. The decreased phoria value by prism lens was classified into three steps; 90~100%, 0~10% and 50% or more. According to results of individual distribution ratio, it was 5, 64 and 24 subjects at 30 minutes after wearing lenses, respectively. The decreased phoria value by spherical lens was classified into three steps; 90~100%, 0~10% and 50% or more. According to results of individual distribution ratio, it was 37, 53 and 41 subjects at 30 minutes after wearing lenses, respectively. The subjects having no phoria changed by both prism and spherical lenses were 37.9%. Conclusions: When prescribing to compensate the near horizontal phoria using prism or spherical lens, the pretest for lens adaptation should be taken before prescription.