• Journal of Korean Ophthalmic Optics Society
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• v.14 no.2
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• pp.1-8
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• 2009

Purpose: The purpose of this study is to compare degrees of asthenopia in after wearing of dispensed reading glasses with different criterion of P.D. Methods: The person who has minus near correction power (distance correction value (-)) is compared to the degree of asthenopia by wearing of dispensed reading glasses with near P.D(-B) and distance P.D. The person who has plus near correction power is compared to degree of asthenopia by wearing of dispensed reading glasses with near P.D-B, distance P.D, near P.D-A. The "Near-P.D-A" means reduced optical centre distance of reading glasses of positive correction value at which the same effect of prism B.O through near visual point in distance glasses exist at near visual point in reading glasses. Results: When near correction value is (-), dispensed reading glasses with distance P.D have caused less asthenopia than dispensed glasses with near P.D-B. When the near correction value is (+), we cannot confirm that which P.D is more useful for reading glasses. As a result of this study, dispensed reading glasses with near P.D-A have caused less asthenopia than another criterion of P.D. Conclusion: The effect of prism B.I through a near visual point in distance glasses ((-) correction value) reduce convergence demand. Therefore (-) correction value-reading glasses support convergence in near vision, because the effect of prism B.I of reading glasses is smaller than that of distance glasses. When the near correction value is (+), centration points can be determined by one of near P.D-A, near P.D-B, distance P.D.

• Journal of Korean Ophthalmic Optics Society
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• v.13 no.4
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• pp.103-107
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• 2008

Purpose: This research measured the near addition powers of presbyopia in wearing the near spectacle for the first time. Methods: We evaluated age, sex, working group, spherical power and cylindrical power and measured the power of refractive error performed the both eyes (310 eyes) of 155 subjects subjectively noncycloplegic and power of addition using the cross cylinder method. Results: There were measured the near addition powers in the range of +0.75D ~ +1.75D. In case of the average addition, they were measured with +1.06D in subjects under 43 years of age, +1.08D in 44 to 46 years, +1.23D in 47 to 49 years and +1.46D in over 50 years of age. The average age in subjects was 47.6 years old and 74 male, 81 female, 71 near sighted working group and 83 far sighted working group. Conclusions: Near addition was correlated with age, working group and cylindrical power (P<0.05, P<0.05, P<0.05).

• Journal of Korean Ophthalmic Optics Society
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• v.16 no.4
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• pp.417-423
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• 2011

Purpose: This study was to investigate that near gradient AC/A ratio could be used to prescribe a patient with distance exophoria, we compared the difference between distance gradient AC/A ratio and near gradient AC/A ratio. Also, this thesis was to understand the relationship between calculated AC/A ratio and gradient AC/A ratio. Methods: Objective and subjective refractive error were corrected and we used Howell (3 m) chart for distance phoria tests and Howell-Kim (40 cm) chart for near phoria tests. The near gradient AC/A ratio and calculated AC/A ratio were used by Howell-Kim (40 cm) combined with +1.00 D, -1.00 D, +2.00 D and -2.00 D. Results: The average value of distance exophoria was 1.17${\pm}$1.17 $\Delta$, and the average value of near exophoria was 3.71${\pm}$2.80 $\Delta$ (t-test. p<0.001). The correlation of distance phoria with near phoria was little higher (r = 0.59, p < 0.001). Gradient AC/A ratios depending on measuring distance and stimulus were higher (r = 0.11~0.53. P < 0.001), when distance was shorter and stimulus to accommodation was more. Also, stimulus to accommodation by plus lens was higher than stimulus to accommodation by minus lens (paired t-test. p < 0.001). There was negative correlation between calculated AC/A ratio and gradient AC/A ratio. As the calculated AC/A ratio was higher, gradient AC/A ratio was lesser. Near gradient AC/A ratio was slightly higher than distance gradient AC/A ratio. Distance and near gradient AC/A ratio taken through the subjective -1.00 D were 1.30 $\Delta$/D and 1.68 $\Delta$/D(t-test. t=1.67, p < 0.001). Conclusions: There is negative correlation between calculated AC/A ratio and gradient AC/A ratio. Also, there is subtle difference between near gradient AC/A ratio and distance gradient AC/A ratio. Therefore, we need to measure distance gradient AC/A ratio when a practitioner prescribe glasses for a patient with distance exophoria.

• Journal of Korean Clinical Health Science
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• v.3 no.4
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• pp.435-443
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• 2015

Purpose. This study was to investigate comparison of the near eye position according to the spectacle and contact lens wearing. Methods. We measured the AC/A ratio and near horizontal phoria using modified Thorington method in each case spectacle and contact lens wearing of equivalent spherical power after measuring the full corrected diopter for 20 subjects (men 5, woman 15, $21.15{\pm}1.35$ years) without specific ocular diseases, ocular surgery experience and vision anomalies. Results. It was shown high correlation between spectacle and contact lens wearing as AC/A ratio is a correlation coefficient 0.99 (p=0.00), near horizontal phoria is a correlation coefficient 0.95 (p=0.00). And contact lens wearing increased as AC/A ratio by $0.32{\pm}1.35$ ${\Delta}/D$ (p=0.31) and near horizontal phoria by $-0.17{\pm}2.18$ ${\Delta}$ (p=0.73) than spectacle wearing but there was no statistically significant difference. As the higher myopic grade AC/A ratio increased and then was shown decreased tendency in -6.00 D < $SED{\leq}-4.00$ D group (p>0.05) and as the higher myopic grade near exophoria increased but there was no statistically significant difference (p>0.05). Conclusions. We should consider that the subjects who had the lower AC/A ratio or higher near exophoria in -6.00 D < $SED{\leq}-4.00$ D group were necessary to measure AC/A ratio and near horizontal phoria when they were wearing contact lens because contact lens wearing tended to increase the near exophoria than spectacle wearing.

• Bulletin of the Korean Mathematical Society
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• v.26 no.2
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• pp.169-173
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• 1989

Let V={(x,y,z):f=z$^{n}$ -npz+(n-1)q=0 for n .geq. 3} be a compled analytic subvariety of a polydisc in $C^{3}$ where p=p(x,y) and q=q(x,y) are holomorphic near (x,y)=(0,0) and f is an irreducible Weierstrass polynomial in z of multiplicity n. Suppose that V has an isolated singular point at the origin. Recall that the z-discriminant of f is D(f)=c(p$^{n}$ -q$^{n-1}$) for some number c. Suppose that D(f) is square-free. then we prove that by Theorem 2.1 .mu.(p$^{n}$ -q$^{n-1}$)=.mu.(f)-(n-1)+n(n-2)I(p,q)+1 where .mu.(f), .mu. p$^{n}$ -q$^{n-1}$are the corresponding Milnor numbers of f, p$^{n}$ -q$^{n-1}$, respectively and I(p,q) is the intersection number of p and q at the origin. By one of applications suppose that W$_{t}$ ={(x,y,z):g$_{t}$ =z$^{n}$ -np$_{t}$ $^{n-1}$z+(n-1)q$_{t}$ $^{n-1}$=0} is a smooth family of complex analytic varieties near t=0 each of which has an isolated singularity at the origin, satisfying that the z-discriminant of g$_{t}$ , that is, D(g$_{t}$ ) is square-free. If .mu.(g$_{t}$ ) are constant near t=0, then we prove that the family of plane curves, D(g$_{t}$ ) are equisingular and also D(f$_{t}$ ) are equisingular near t=0 where f$_{t}$ =z$^{n}$ -np$_{t}$ z+(n-1)q$_{t}$ =0.}$ =0.

• The Korean Journal of Vision Science
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• v.20 no.4
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• pp.523-530
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• 2018

Purpose : The purpose of this study was to investigate the difference in the dynamic visual acuity between (DVA) the distance and near and the effect of change of accommodative stimulus on the dynamic visual acuity by the addition of the plus lens. Methods : The study involved 40 male and female adults ($22.84{\pm}2.43$ years old) with over 1.0 of visual acuity and without systemic disease or ocular disease. We compared the distance and near DVA and the change of DVA induced by the addition of the plus lens(+0.50D, +1.00D, +1.50D). Results : The distance DVA and near DVA are $78.86{\pm}19.46deg/sec$ and $76.90{\pm}18.05deg/sec$ respectively. The distance DVA was slightly higher(p=0.04). The higher the distance DVA, the higher the positive correlation with the near DVA and distance DVA, and distance DVA was higher in those who had higher the near DVA(r=0.95, p=0.00, Fig. 4). The near DVA according to the change of accommodative stimulus was $75.95{\pm}18.85deg/sec$ in full correction and the near DVA with +0.50D spherical power was $76.95{\pm}16.45$ but there was no statistically significant differences(p>0.05). However, the near DVA with +1.00D spherical power was $79.02{\pm}13.51deg/sec$ and it was slightly higher. Also, the near DVA with +1.50D spherical power was $84.28{\pm}18.96deg/sec$, there and it was statistically significant difference(p<0.05). Conclusion : There is no difference between distance and near DVA, but near DVA is also excellent if distance DVA is good. The DVA increases as added a plus lens for controlled accommodative stimulation changes.

• Journal of Korean Neurosurgical Society
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• v.65 no.4
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• pp.572-581
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• 2022

Objective : Compared to microscopes, exoscopes have advantages in field-depth, ergonomics, and educational value. Exoscopes are especially well-poised for adaptation into fluorescence-guided surgery (FGS) due to their excitation source, light path, and image processing capabilities. We evaluated the feasibility of near-infrared FGS using a 3-dimensional (3D), 4 K exoscope with near-infrared fluorescence imaging capability. We then compared it to the most sensitive, commercially-available near-infrared exoscope system (3D and 960 p). In-vitro and intraoperative comparisons were performed. Methods : Serial dilutions of indocyanine-green (1-2000 ㎍/mL) were imaged with the 3D, 4 K Olympus Orbeye (system 1) and the 3D, 960 p VisionSense Iridium (system 2). Near-infrared sensitivity was calculated using signal-to-background ratios (SBRs). In addition, three patients with brain tumors were administered indocyanine-green and imaged with system 1, with two also imaged with system 2 for comparison. Results : Systems 1 and 2 detected near-infrared fluorescence from indocyanine green concentrations of >250 ㎍/L and >31.3 ㎍/L, respectively. Intraoperatively, system 1 visualized strong near-infrared fluorescence from two, strongly gadolinium-enhancing meningiomas (SBR=2.4, 1.7). The high-resolution, bright images were sufficient for the surgeon to appreciate the underlying anatomy in the near-infrared mode. However, system 1 was not able to visualize fluorescence from a weakly-enhancing intraparenchymal metastasis. In contrast, system 2 successfully visualized both the meningioma and the metastasis but lacked high resolution stereopsis. Conclusion : Three-dimensional exoscope systems provide an alternative visualization platform for both standard microsurgery and near-infrared fluorescent guided surgery. However, when tumor fluorescence is weak (i.e., low fluorophore uptake, deep tumors), highly sensitive near-infrared visualization systems may be required.

• Communications of the Korean Mathematical Society
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• v.28 no.4
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• pp.669-677
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• 2013

In this paper we introduce the notion of NI near-rings similar to the notion introduced in rings. We give topological properties of collection of strongly prime ideals in NI near-rings. We have shown that if N is a NI and weakly pm near-ring, then $Max(N)$ is a compact Hausdorff space. We have also shown that if N is a NI near-ring, then for every $a{\in}N$, $cl(D(a))=V(N^*(N)_a)=Supp(a)=SSpec(N){\setminus}int\;V(a)$.

• Journal of the Optical Society of Korea
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• v.18 no.2
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• pp.110-117
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• 2014

In this study, we objectively determined whether the ReSTOR as a multifocal IOL (intraocular lens) has a multifocal function compared to the IQ as a monofocal IOL in vivo by OQAS (Optical Quality Analysis System). Eighteen patients who had cataract surgery with implantation of ReSTOR (27 eyes) and 15 patients with IQ (21 eyes), were included inthis study. Uncorrected distance visual acuity (UCDVA), corrected distance visual acuity (CDVA), uncorrected near visual acuity (UCNVA)and distance corrected near visual acuity (DCNVA) were measured. After setting the artificial pupil size to 3 mm, we performed 'Optical quality'. We inputted defocus diopters of (objective spherical refraction)(far), (objective spherical refraction-1.25 D)(intermediate),(objective spherical refraction-2.5 D)(near), and (objective spherical refraction-3.5 D)(very near) into 'selected spherical refraction' simulating the optical quality at far, intermediate, and near distance. We changed the pupil size to 5 mm and repeated the same measurements. The UCDVA and CDVA did not show significant differences between the 2 groups. But, the UCNVA and DCNVA of the ReSTOR group were better than those of the IQ group (p=0.000, p=0.000). For 3 mm pupil, at far distance, modulation transfer function (MTF) cut off and point spread function (PSF) width at 50% of ReSTOR were worse than those of IQ (p=0.039, p=0.020). At intermediate distance, MTF cut off, Strehl ratio and PSF width at 50% of ReSTOR were worse than those of IQ (p=0.001, p=0.001, p=0.000). At near distance, MTF cut off of ReSTOR was worse than that of IQ (p=0.033). At very near distance, MTF cut off and Strehl ratio of ReSTOR were worse than those of IQ (p=0.002, p=0.002), but PSF width at 50% of ReSTOR was better than that of IQ. For 5 mm pupil, most parameters at each distance, there was no significant difference between the 2 groups. Only PSF width at 50% of ReSTOR were worse than those of IQ at intermediate distance (p=0.013). It was impossible to show the multifocal function of ReSTOR compared to the IQ byOQAS.

• Journal of Korean Ophthalmic Optics Society
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• v.20 no.3
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• pp.319-324
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• 2015

Purpose: This study was designed to evaluate the changes of phoria and calculated AC/A ratio, and their recovery time points by watching 3D television (3D TV). Methods: 50 subjects (male 30, female 20) of 20s to 40s ages who can watch 3D, were measured phoria using a Howell phoria card at 3 m for distance and 40 cm for near. The phoria was evaluated before watching 3D TV and every 10 minutes from starting of watching 3D TV for 30 minutes, and every 5 minutes after finishing of watching 3D TV for 30 minutes again. Results: For the distance phoria during and after watching 3D TV, it was increased to more exophoria $-0.98{\pm}1.37{\Delta}$ (prism diopters) after 10 minutes from starting of 3D TV watching (p=0.063) and increased to more exophoria $-1.00{\pm}1.28{\Delta}$ after 30 minutes (p=0.024), and started to decrease after finishing of watching 3D TV and recovered to the level of before 3D TV watching ($-0.78{\pm}1.11{\Delta}$) after 20 minutes (p=0.32) with comparing to phoria of before watching 3D TV ($-0.80{\pm}1.12{\Delta}$). For the near phoria, it was also increased to more exophoria $-5.71{\pm}4.45{\Delta}$ after 10 minutes from starting of watching 3D TV (p=0.000) and $-6.58{\pm}4.36{\Delta}$ after 30 minutes (p=0.000), and started to decrease after finishing of watching 3D TV and recovered to the level of before watching 3D TV after 20 minutes ($-4.34{\pm}3.67{\Delta}$) (p=0.32) with comparing to the phoria of before watching 3D TV ($-4.36{\pm}3.66{\Delta}$). AC/A ratio was decreased from $4.92{\pm}1.17{\Delta}/D$ for before 3D TV watching to $4.11{\pm}1.50{\Delta}/D$ for after 30 minutes from starting of watching 3D TV (p=0.000), and increased after the end of watching 3D TV and recovered to the level of before 3D TV watching ($4.93{\pm}1.18{\Delta}/D$) after 25 minutes (p=0.598). Conclusions: During watching 3D TV at near, it showed a tendency of convergence insufficiency by decrease of calculated AC/A ratio as result that exophoria at near was higher increased than exophoria at distance. However, the increased exophoria at both near and distance was recovered to the level of base line after 25 minutes from the end of watching 3D TV. Through this study, it seems to need rational proposals of advice for watching 3D TV.