• 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.18 no.3
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• pp.341-346
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• 2013

Purpose: The purpose of this study was to evaluate whether a relationship exists between head posture and phoria, and usefulness in examining habitual head posture. Methods: Twenty two subjects (20 males and 2 females, mean age $23.6{\pm}2.7$ years) with abnormal phoria from participants randomized were enrolled in this study. For all subjects, testing included case history, cover test, refraction, phoria and vergence test. Habitual head posture (head posture, head tilt and face turn) was measured by Impression IST, and observed by examiners. Results: The abnormal head posture was revealed in some subjects with abnormal phoria. Spearman' correlation ($\rho$=0.524, p=0.045) showed significant correction between face turn and phoria at distance in 15 subjects with prism prescription. No significant relationship between head posture and phoria was found in subjects with abnormal phoria. The objective measurement and subjective observation of head posture showed insignificant correction but there was a distinct difference. The former was detail and the latter was discriminate. Conclusions: Presence of abnormal head posture was found in phoric subjects. The results indicate the need to observe habitual head posture at all major positions of gaze in phoria.

• Journal of Korean Ophthalmic Optics Society
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• v.9 no.1
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• pp.93-104
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• 2004

In order to have a comfortable vision without any asthenopia in work place, it is very necessary to make a complete binocular correction in addition to the perfect correction of refractive deficits. For this, At first, the exact understanding of the required corrective value of the existing angular ametropia(associated phoria) is needed. The fact likely seems fact that a correction of refractive deficits could not to be reached with single optotype, the corrections of angular ametropia(associated phoria) with single optotype is impossible. The reason is that a most ametropia(associated phoria) is accompanied with the fixation disparity. To make a perfect measurement of ametropia(associated phoria), at least, 3 kinds of optotype is essential. This fact could be explained by stating the fusional stimulus in the binocular refraction tests on each eye. If these types of three tests have not practical practice. The most of many cases may result in undercorrection.

• 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.

• Journal of Korean Ophthalmic Optics Society
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• v.18 no.3
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• pp.313-320
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• 2013

Purpose: This study compared the quantity of phoria for distance by new method with that by existing methods. Methods: For this study, it was selected to two existing phoria measurements, von Graefe and Maddox rod. And new method named "3D polarizing phoria measurement" was designed to measure the quantity of phoria using polarizing glasses and 3D display. Unlike existing measurement using polarized lens, newly considered method measured the quantity of phoria in condition removed perfect binocular fusion using field stop on apparatus and polarized lens. For using new method for distance, it was developed a phoria test chart. It supports three kinds of phoria measurements. Subjects were 12 (male 6, female 6). They had three phoria tests (1 sets) including new method. It was considered the effect of experimental order, so we tested all cases about experimental order. The number of cases was 6 sets, and the sample size in this experiment was 72 sets. For removing binocular fusion, lighting of the laboratory that was below 10 lx and the background color of phoria test chart was dark, RGB=(20, 20, 20). Results: Subjects were sorted into three groups. Samples with exophoria and orthophoria were 30 sets each, and those with esophoria were 12 sets. The quantity of phoria measured three tests differ from each other like "newmethod < von Graefe < Maddox rod", and there were statistically significant difference each other. Conclusions: This study has great significance in the sense that new method was the measurement with naturally removing binocular fusion without dizziness during the tests.

• Journal of Korean Ophthalmic Optics Society
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• v.1 no.2
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• pp.77-84
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• 1996

As the results of phoria measurement of Korean adults for 106 males and 55 females, the elevens (6.8%) are orthophoria, the nineties (55.9%) are esophoria and the fifty fives (34.2%) are exophoria respectively. Also the thirty threes (20.4%) are right hyperphoria against the left eye and the thirty eights (23.6%) are left hyperphoria against the right eye. Horizontal phoria is below $10{\Delta}$ mostly and vertical phoria is below $5{\Delta}$.

• Journal of Korean Ophthalmic Optics Society
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• v.13 no.1
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• pp.101-105
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• 2008

Purpose: In this study we measured the mean value of the distance stereoacutiy for adult subjects and evaluated the variation of the distance stereoacuity according to correction of phoria using the Pola Test E-II of Carl Zeiss. Methods: We investigated the distance stereoacuity for 50 adults (male: 29, female: 21) ranging in age from 19 to 46 years using D6 Circle chart and D8 Line chart in the Pola Test E-II. Results: The mean values of the distance stereoacuity measured on the D6 Circle test and D8 Line test were 159.6 and 149.4 seconds of arc respectively. The mean variations of the distance stereoacuity according to correction of phoria in D6 Circle test were increased 43.2 seconds of arc in exophoria and 51 seconds of arc in esophoria, and those in D8 Line test were increased 42 seconds of arc in exophoria and 70.2 seconds of arc in esophoria. Conclusions: We knew from these results that the distance stereoacuity after prescription of phoria improved more esophoria than exophoria.

• Journal of Convergence for Information Technology
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• v.8 no.6
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• pp.101-106
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• 2018

We examined refractive error, the corrected visual acuity, phoria and fusional reserve of 114 healthy myopes and hyperopia who had no strabismus, no ocular and physical diseases. We evaluated the occurrence of asthenopia according to phoria and fusional reserve. 41 out of 114 subjects which exophoria was 69% and esophoria was 5.5%, orthophoria was 26% made a complaint against asthenopia. The subjects who had exophoria of $0-6{\Delta}$ in the range of normal state was 61.4%, while the subjects who had exophoria of $7{\Delta}$ or more in the range of abnormal state was 38.6%. Reducing fusional reserve was associated with increasing phoria. The fusional reserve twice or more than phoria were 27.2%, and twice or under were 72.8%. Futhermore, AC/A ratio for heterophoria was found from 1.0 to 12.6 and its relationship to asthenopia of phoria could not be determined.

• Journal of Korean Ophthalmic Optics Society
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• v.9 no.2
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• pp.361-370
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• 2004

The purpose of this study was to evaluate the outcome and Factors that influence the quantity of Phoria in the low correction and perfect correction. Also the coincidence with the opticenter and the pupillary distance was a principal factor that influence the quantity of Phoria. Thereupon, this study is attributed to promote the perfect Phoria test. The subjects for this study were 120 persons(240 eye) in myopic refractive errors. ISP/WIN program was used for the data analysis. The collected data was analyzed by descriptive statistics and Spearman's correlation coefficient. The results of this study were as follows: 1. The prism pattern was difference between low correction and perfect correction in the Phoria test. The proportion of orthophoria was changed from 10.0% to 12.5%, exophoria was changed from 67.5% to 62.5%, and esophoria was changed from 22.0% to 32.5%, respectively. 2. The average of optical center distance and pupillary distance were 31.70mm and 31.49 mm, respectively. 3. Among the 120 myopic glasses wearers, the distance between optical centers was coincided with the pupillary distance in 37.5%, and discrepant in 62.5%. 4. For the patients who were coincided with the pupillary distance, the proportion of exophoria decreased 53.33%, esophoria increased 20.0%. 5. For the changing of the quantity of Phoria in the low correction, the degree of exophoria decreased 1.11 prism diopters in the perfect correction, esophoria increased 0.39 prism diopters.

• Journal of Korean Ophthalmic Optics Society
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• v.20 no.1
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• pp.67-73
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• 2015

Purpose: This study was investigated the relationship between the male and female of near stereoacuity and phoria, and was examined the correlations between near stereoacuity and phoria and refractive error. Methods: Adult 83 (male 36, female 47, mean age $21.09{\pm}1.74$(19~29) years old) target was examined after full correction of refractive error. Near stereoacuity was measured by using Titmus-fly Stereotest(Stereo Optical Co., Inc., Chicago, IL, USA), and RANDOT Stereotest (Stereo Optical Co., Inc., Chicago, IL, USA), phoria was measured by using modified torrington method, at distance 40 cm. Results: In near stereoacuity, male was better good than female, and there was no difference between male and female (p>0.05). In near phoria, female was more higher than male, and there was a significant difference between male and female (p<0.05). Near stereoacuity by Titmus-fly test and Randot test result respectively was $262.17{\pm}562.43$ sec (second of arc) $243.08{\pm}68.04$ sec in esophoria, $148.42{\pm}269.54$ sec, $107.40{\pm}263.74$ sec in orthophoria, $113.94{\pm}152.46$ sec, $79.70{\pm}136.83$ sec in exophoria, there was a no difference between three phoria groups (p>0.05), and was a high correlation between phoria and near stereoacity(r=0.68). In addition, near stereoacuity in the refractive error respectively was $80.00{\pm}571.43$ sec, $68.75{\pm}36.82$ sec in myopia, $133.57{\pm}224.15$ sec, $93.14{\pm}214.95$ sec in hyperopia, $511.20{\pm}855.00$ sec, $511.4{\pm}855.60$ sec, there was a significant difference between three phoria groups (p<0.05). when was classfiied near stersoacuity into degree of refractive error, near stersoacuity was best in emmetropia, and was reduced when refractive error was highest in high degree myopia, and hyperopia. Conclusions: Titmus-fly Stereotest and RANDOT Stereotest result, near stereoacuity of adults, when esophoria and high degree refractive error, was reduced, there was a relationship between near stereoacuity with phoria, and refractive error. In this both stereotests if was bad when near stereoacuity can expect a phoria and refractive error.