• Journal of Korean Ophthalmic Optics Society
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• v.13 no.2
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• pp.37-41
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• 2008

Purpose: The purpose of this case study is to prescribe a prismatic correction in uncommon case of cyclovertical heterophoria. Methods: The prescribed prism was used to balance the vertical vergence break values by the binocular vision evaluation such as phoria, vergence, accommodative function and the others. Results: Although asymptomatic lateral phoria was changed, the vertical prismatic correction improved the symptoms such as eyestrain, headaches, diplopia and others. And cyclophoria was disappeared by prismatic correction. Conclusions: The prismatic correction for this case was useful for alleviating symptoms of cyclovertical deviations.

• Journal of Korean Ophthalmic Optics Society
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• v.20 no.2
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• pp.229-235
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• 2015

Purpose: This study was undertaken to study on visual function before and after prescription of vertical prism. Methods: 80 subjects (10-30ages) who had been precribed vertical prism and 1 year after they were represcribed vertical prism. Results: Phoria (p=0.000), supra vergence (p=0.000), NPC (p=0.003), NPA (right eye) (p=0.005), NPA(left eye) (p=0.000) showed a significant change. Conclusion: Vertical prism prescription was reduced during revisit. Supra vergence, NPC, NPA(right eye), NPA(left eye) showed a significant change. Binocular Accommodative lag was not associated with vertical prism prescription and binocular vision findings.

• Journal of Korean Ophthalmic Optics Society
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• v.11 no.2
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• pp.77-83
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• 2006

We have studied the astigmatism according to the bevel position and the tilting(pantoscopic) angle of decentered spectacle lens for prism prescription. For prism prescription, generally we make a general spectacle lens into decentered spectacle lens. At this time the bevel position of decentered lens is a important matter, because the difference between optic axis and visual axis occur aberrations. Using the calculation we find that the case that the axis of bevel rotation band passes the front curvature center of (+) lens has a smaller astigmatism than the case that the axis of bevel rotation band passes the rear curvature center of (+) lens and that the case that the axis of bevel rotation band passes the rear curvature center of (-) lens has a smaller astigmatism than the case that the axis of bevel rotation band passes the front curvature center of (-) lens. We find the lens with higher refraction index has a smaller astigmatism.

• Journal of Korean Ophthalmic Optics Society
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• v.15 no.2
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• pp.155-160
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• 2010

Purpose: The purpose of this study was to evaluate how phoria variations would vary with head positions, as well as to review the need to differentiate prism placement over either eye in a relation to the imbalance of the extraocular muscle. Methods: This study was carried out with 44 males (88 eyes) and 16 females (32 eyes) aged between 20 and 30. For all subjects, testings were performed using cover test, subjective refraction, phoria and vergence test. To analyze phoria variations comparatively for the head tilt test and the face turn test, phoria deviation were measured using the von Graefe. Results: For the phoria variation related with head tilt and face turn, a significant difference was observed in the group judged to be abnormal on the horizontal phoria of Morgan' norm (p<0.05); especially in patients who needed near prescription of Sheard's criterion, a higher variation was observed (p<0.05). The abnormal group was composed of patients who needed distance prescription of Sheard's criterion and ones who did not need the prescription, all of whom showed phoria variations, but the mean value was less than the near. Conclusions: With regard to the head tilt and face turn related phoria level, the patients who needed near horizontal prism prescription of Sheard's criterion showed a remarkably higher variation. Altogether, it is deemed to check whether extraocular muscles are ill-balanced in both eyes previously to determine the prism power on phoria level to the end that each of prism powers may be accurately determined.

• Journal of Korean Ophthalmic Optics Society
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• v.20 no.3
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• pp.341-347
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• 2015

Purpose : This study was to examine a correlation of response AC/A ratio by additional spherical powers with PD(Pupilary distance) and relative accommodation, and was to investigate correlation of CA/C ratio by prism powers. The mean differences between a reciprocal response AC/A ratio and a CA/C ratio were compared, and were suggested to be used as data in the refractive power and prism prescriptions in the clinical. Methods: The open field autorefractometer (Nvision-K 5001, Shin nippon) and Howell target at 40 cm fixation distance to 62 persons with average $22.62{\pm}2.84$ ages were used to measure the response AC/A ratio according to additional Spherical powers. The CA/C ratios were measured using the DOG card at 40cm according to prism powers. Results: When the response accommodation according to Additional Spherical power changes and the response accommodation according to prism power changes were compared, it was larger than the response accommodation according prism power change. These were significant differences statistically. The correlation of response AC/A ratio and PD is showed as r = -0.158, the CA / C ratio is shown as r = 0.093. The correlation of response AC/A ratio and relative accommodation showed as r = -0.253, the CA/C ratio showed as r = 0.566 that is predictable correlation. The correlation of response AC/A ratio and CA/C ratio showed as r = -0.355 that is low minus correlation (p = 0.000). The difference between a reciprocal response AC/A ratio and a CA/C ratio showed $0.12{\pm}0.06D/{\Delta}$ with a significant difference statistically (p=0.000). Conclusions: The correlation of relative accommodation and CA/C ratio showed that depend on the individual, The more a relative accommodation is, the higher a response accommodation of convergence by convergence stimulus is. The reciprocal response AC/A and CA/C ratio showed significant differences statistically. This can have higher CA/C ratio in patients with low AC/A ratio in clinical as an independent variable. Thus when the abnormal binocular vision was prescribed in the clinical, it is necessary to consider the accommodative response even if the AC/A ratio is a normal range.

• Journal of Korean Ophthalmic Optics Society
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• v.15 no.1
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• pp.61-66
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• 2010

Purpose: This study was performed to determine vertical fixation disparity by Fixation Disparity Card. The purpose of this study was to investigate distribution of the curve types obtained with Wesson card. Methods: Fixation disparity curves were measured on 52 subjects with the Wesson fixation disparity card. A fixation disparity curve was an x, y coordinate plot of the angular amount of fixation disparity as a function of the power of prisms through which the patient views. The fixation disparity curve variables that were used to aid in the diagnosis and management of binocular vision disorders included the x-intercept, y-intercept, curve slope and curve type. Results: Vertical fixation disparity curves by Wesson Fixation Disparity Card were very various. Conclusions: Vertiical fixation disparity curves could be used to aid in the diagnosis and prescription.

• Journal of Korean Ophthalmic Optics Society
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• v.15 no.2
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• pp.137-144
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• 2010

Purpose: This study was to evaluate the clinical performance of 1-Day disposable toric soft contact lenses (TSCL) and to compare the visual performance with glasses and TSCL. Methods: In a two-week investigation of 'prism ballast' designed TSCL, occular refractions in 15 (30 eyes) healthy subjects were within the range of -2.75 D TO -8.00 D spherical power and -0.75 DC to -2.25 DC cylinderical power (with-the-rule). Subjects were assessed the clinical performance (orientation, centration, movement, tightness, rotation recovery, symptoms) of TSCL and compared binocular vision and contrast sensitivity with corrected glasses and TSCL at initial and two-week follow-up visits. Results: The prism-ballast design TSCL achieved better orientation, rotation recovery and symptoms over 2 week period. There was no statistically significant difference between spectacles and TSCL with respect to measuring binocular vision and contrast sensitivity. Conclusions: The clinical performance was good with prism-ballast design toric soft contact lenses. Evaluation of binocular vision and contrast sensitivity did not show the differences between spectacles and TSCL correction. This study suggests that TSCL wearers can be achieved similar visual performance for spectacles wearers.

• Journal of Korean Ophthalmic Optics Society
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• v.12 no.1
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• pp.53-59
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• 2007

A commonly used device to determine fixation disparity curves is the Wesson Fixation Disparity Card. A fixation disparity curve is an x, y coordinate plot of the angular amount of fixation disparity as a function of the power of prisms through which the patient views. The fixation disparity curve variables that are used to aid in the diagnosis and management of binocular vision disorders include the x-intercept, y-intercept, curve slope and curve type. Fixation disparity curves were measured on 102 subjects with the Wesson fixation disparity card. The purpose of this study is to investigate distribution of the curve types obtained with Wesson card. Fixation Disparity by Wesson Fixation Disparity Card were that in case of type I 63.0%, in case of type II 0.0%, in case of type III 25.0% and in case of type IV 12.0%.

• 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.13 no.1
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• pp.15-20
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• 2008

Purpose: To study on the confidence of dry eye diagnosis methods which need to prescribe contact lens. Methods: Non-invasive tear film break-up time (NIBUT) and tear film break-up time (TBUT) were measured in forty healthy subjects in their 20s, and then the subjects were classified into normal eye and dry eye. The results of McMonnies questionnaire, tear prism height measurement, Hardtack test, blink rate measurement and Schirmer test were compared with the results of NIBUT and TBUT. Results: The results of NIBUT and TBUT were as follows; 20 subjects had normal eyes, 10 subjects had dry eyes in both NIBUT and TBUT, and 10 subjects showed different results. In McMonnies questionnaire, the score of normal eye group averaged 8.2 and that of dry eye group averaged 18.5, which showed statistically significant difference. Furthermore, 100% of normal eye group classified by the results of NIBUT and TBUT corresponded with the result of McMonnies questionnaire and 90% of dry eye group showed the correspondence. Tear prism height of normal eye group averaged 0.32 mm and that of dry eye group averaged 0.23 mm, which were significantly different. Hardtack test, blink rate measurement and Schirmer test without local anesthesia showed no statistically significant difference between normal eye group and dry eye group. Conclusions: On dry eye diagnosis methods, the results of McMonnies questionnaire and tear prism height measurement had close correlation with the results of NIBUT and TBUT.