• Journal of Korean Ophthalmic Optics Society
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• v.18 no.4
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• pp.357-363
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• 2013

Purpose: To investigate the visual function with prescription swimming goggles. Methods: 15 university students (mean age: $22{\pm}1.54$ years) participated, with a mean distance refractive error of RE: S-1.67 D/C-0.40 D, LE: S-1.70D/C-0.37 D. Inclusion criteria were no ocular pathology, able to wear soft contact lenses to correct their refractive error to emmetropia and able to swim. Participants were fitted with contact lenses to correct all ametropia. Subjective evaluation for satisfaction of visual acuity, asthenopia and balance were also measured using a questionnaire while wearing swimming goggles with cylinder (C+1.50 D, Ax $90^{\circ}$) compared with plano sphere outside the swimming pool area. Visual acuity was assessed using the same ETDRS chart. The prescription swimming goggles powers were assessed in random order and ranged in power from S+3.00 D to S-3.00 D in 0.50 D steps. Results: Subjective evaluation was significantly worse for the swimming goggles with cylinder than for the plano powered goggles for all 3 questions, visual acuity, asthenopia and balance. Visual acuity were significantly affected by the different power of the swimming goggles (p<0.05), but there was no significant difference between the in-air in-clinic and underwater in-swimming pool measures (p=0.173). However, visual acuity measured in the clinic was significantly better than underwater for some swimming goggle powers (+3.00, +1.00, +0.50, 0, -1.00 and -2.00 D). Conclusions: Wearing swimming goggles underwater may degrade the visual acuity compared to within air but as the difference is less than 1 line of Snellen acuity, and it is unlikely to result in significant real-life effects. Having an incorrect cylinder correction was found to be detrimental resulting in lower score of satisfaction. Considering slippery floor of swimming pool area, it can be a potential risk factor. Therefore, it is important to correct any refractive error in addition to astigmatism for swimming goggle.

• Journal of Korean Ophthalmic Optics Society
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• v.19 no.4
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• pp.551-555
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• 2014

Purpose: This study is to investigate if the improvement of visual sensory (VS) by amblyopia treatment affects the ocular functions in refractive errors, accommodative errors and phoria at distance and near. Methods: 10 subjects (17 eyes, mean age of $10.7{\pm}2.9$ years) who treated amblyopia completely, were participated for this study. Refractive errors, accommodative errors, and distance and near phoria were compared between before and after treatments of amblyopia. Refractive errors and accommodative errors at 40 cm were measured using openfield auto-refractor (NVision-5001, Shin Nippon, Japan) and using monocular estimated method (MEM) respectively. Phoria was determined at 3 m for distance and at 40 cm for near using Howell phoria card, cover test or Maddox rod. Results: Mean corrected visual acuity (CVA) significantly increased from $0.46{\pm}0.11$ (decimal notation) for before amblyopia treatment to a level of $1.03{\pm}0.13$ for after amblyopia treatment (p < 0.001). For spherical refractive error, hyperopia significantly decreased from $+2.29{\pm}0.86D$ to a level of $+1.1{\pm}2.38D$ (p < 0.05) but astigmatism did not significantly change; $-1.80{\pm}1.41D$ for before treatment and $-1.65{\pm}1.30D$D for after treatment (p > 0.05). Accommodative error significantly decreased from accommodative lag of $+1.1{\pm}0.75D$ to a level of $+0.5{\pm}0.59D$ (accommodative lag) (p < 0.05). Distance phoria significantly changed from eso $2.9{\pm}6.17PD$ (prism diopters) to a level of eso $0.2{\pm}3.49PD$ (p < 0.05), and near phoria also significantly changed from eso $0.4{\pm}2.32PD$ to level of exo $2{\pm}4.9PD$ (p < 0.05). There was a high correlation (r = 0.88, p < 0.001) between improvement of visual acuity and decrease of accommodative lag. Conclusions: Hyperopic refractive error decreased with improvement of CVA or VS by amblyopia treatment. And the improvement of VS by amblyopia treatment also improved accommodative error, and changed phoria coupled with accommodation.

• Journal of Korean Ophthalmic Optics Society
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• v.8 no.2
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• pp.169-175
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• 2003

This research reviewed that 83 male subjects. 89 female subjects of middle and high school visited D Optical shop at the downtown of Daegu more than twice from January, 1999 to January, 2003 and obtained the following results by using the visual acuity prescription of them for which D Optical shop was keeping. 1. The classification of correction power for 190 myopia eyes was examined (87 male eyes, 103 female eyes) showed 89 eyes(46.82%) between $0.25D{\leq}3.00D$, 86 eyes(45.26%) between $3.25D{\leq}6.00D$, 15 eyes(7.89%) for over 6.25D. 2. The kind of 154 astigmatism subjects(79 male eyes, 75 female eyes) was direct astigmatism 83.77%, reverse astigmatism 11.69%, oblique astigmatism 4.55%. The cylindrical correction power for astigmatic eyes was 61 eyes(39.61%) between $0.25D{\leq}0.50D$, 60 eyes(38.96%) between 0.50D<1.00D, 121 eyes(78.57%) for less than 1.06D, 6 eyes(0.65%) for over 3.00D. 3. The variation of spherical power showed 161 eyes(46.80%) between $0.00D{\leq}0.50D$, 109 eyes(31.69%) between $0.51D{\leq}1.00D$, 17 eyes(4.94%) for over 2.01D variation. 4. The variation of astigmatic power showed 92 eyes(59.74%) between $0.00D{\leq}0.50D$, 39 eyes(25.32%) between $0.26D{\leq}0.50D$, 10eyes (6.49%) between $0.51D{\leq}0.75D$, 13 eyes(8.44 %) for over 0.76D astigmatic variation. 5. The variation of equivalent spherical power showed 137 eyes(39.83%) between $0.00D{\leq}0.50D$, 126 eyes(36.63%) between $0.51D{\leq}1.00D$, 40 eyes(11.63%) between $1.01D{\leq}1.50D$, 21 eyes(6.10%) between $1.51D{\leq}2.00D$, 20 eyes(5.81%) for over 2.01D variation.

• Journal of the Korea society of information convergence
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• v.6 no.1
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• pp.37-41
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• 2013

In this study, by using the Oculus Pentacam, we analyzed the relationship of corneal front astigmatism corneal and the radius of curvature of the rear face of the 20's to 40's. The vertical radius of curvature were man 7.94mm (${\pm}0.22$), women 7.87mm (${\pm}0.21$), the horizontal radius of the anterior corneal appeared man 7.69mm (${\pm}0.27$), women 7.63mm(${\pm}0.23$). And rear vertical radius of curvature were man 6.52mm(${\pm}0.23$), woman 6.55mm (${\pm}0.22$), the horizontal radius of the anterior corneal appeared man 6.06mm (${\pm}0.24$), woman 6.08mm(${\pm}0.24$). The results of correlation analysis between the radius of corneal posterior surface and the anterior corneal surface, it was found out that there is a significant correlation. In this study, similar results were obtained anterior surface of the cornea, the radius of curvature of the rear surface, the refractive power, and astigmatism, as other papers that have been reported. But in this paper, the cornea thickness was thicker than other previously reported paper.

• Journal of Korean Ophthalmic Optics Society
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• v.21 no.1
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• pp.77-81
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• 2016

Purpose: This study was performed to investigate the difference of meridional visual acuity and the loss of corrected visual acuity (VA) in order to emphasis the importance of astigmatic correction. Methods: 64 subjects (122 eyes) aged $22.75{\pm}2.36years$ participated in this study. After full correction of astigmatic refractive error, VA was measured in which the direction of the slit filter was matched with astigmatic axis and $90^{\circ}$ to the astigmatic axis. Results: 52 eyes showed no difference in VA between the two direction. However 70 eyes had difference VA between them. 14 out of 52 eyes and 24 out of 70 eyes had under 1.0 in monocular VA. The astigmatic degree was higher in the existence of VA difference between the two direction than non-existence. The difference is higher with under 1.0 monocular VA. Monocular VA is closely related to the focal line having better VA in the principal focal line. Glasses replacement period was analyzed as 6~12 months for the preservation of better VA. Conclusions: The final glasses prescription has to be given with full correction because continued under-correction for astigmatism causes meridional VA difference.

• Journal of Korean Ophthalmic Optics Society
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• v.5 no.2
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• pp.59-64
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• 2000

We performed refraction, keratometry, slit lamp biomicroscopy. We selected 58 current spherical RGP lens wearers for this three-month study. All patients exhibits at least 0.75D of corneal astigmatism measured with the keratometer, and 37 patients had corneal astigmatism of 1.50D or greater. At least follow-up visit, we measured Snellen acuity with lenses, and performed overrefraction, overkeratometry and slit lamp biomicroscopy. We charted lens position, movement and surface quality. During the three month, biomicroscopy revealed no corneal edema and neovascularization on any patients. Fluorescein staining were 52 patients case of grade 0.5 patients case of grade 1, and 1 patient case of grade 2. In evaluating post-fit residual cylinder, on overrefraction as a percentage of refractive cylinder. By the initial visit, one-week visit, one-month visit, and two-month visit are 41%, 34%, 29%, respectively. In this data, we knew no change after one month. The average overrefraction for these eyes in absolute diopters is 0.26D(initial visit), 0.22D(one-week visit, 0.17D(one-month visit), and 0.16D(two-month visit). The use of a regimen containing a dedicated daily cleaner was more effective in maintaining patient comfort and lens cleanliness than was the use of a regimen containing only a multipurpose solution.

• 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 Korea Convergence Society
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• v.9 no.12
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• pp.273-279
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• 2018

This study researched how the refraction error and illumination influence to contrast sensitivity when we wear the circle contact lenses. The study population comprised 16 students and adults(5 of Male, 11 of Female). The study population comprised 16 students and adults(5 of Male, 11 of Female), We measured the contrast sensitivity on uncorrected vision, according to color of circle contact and change the illumination of laboratory. The contrast sensitivity by illumination decreased than unaided vision when they wore the color contact lenses and more increased mesopic than photopic. Compared between black and brown lenses, brown was higher the contrast sensitivity than black. Also emmetropia had significantly differences when we compared the contrast sensitivity of subjects who had emmetropia, myopia and myopia astigmatism whether refractive error has or not. Therefore, it is important to provide sufficient understanding and recognition of color contact lenses.

• Journal of Korean Ophthalmic Optics Society
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• v.12 no.3
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• pp.71-75
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• 2007

This research was conducted from 1 March 2005 to 28 February 2007. We collected data from optician stores around Kwang-Ju city, 208 people aged 40 to 80 years using the cross cylinder method to find out age and gender dependence of near addition. 1. Age dependence of Refractive error shows 5% of emmetropia 34% of myopia and 43% of hyperopia. These results reveal that rate of hyperopia is higher than emmetropia and myopia. Mixed Astigmatism rate was 18%. 2. Near addition required to correct Presbyopia is analyzed as functions of gender and ages. In case of man: 40-44 (+0.75D), 45-49(+1.25D), 50-54(+1.41D), 55-59(+1.92D), 60-64(+2.35D), 65-69(+1.97D), 70(+3.12D), In case of woman: 40-44 (+1.08D), 45-49 (+1.38D), 50-54 (+1.67D), 55-59(+2.05D), 60-64 (+2.50D), 65-69 (+2.57D), $70{\leq}(+3.18D)$. Result shows it's Adding power higher than man. 3. Age dependence of Axis of Astigmatism. In case of horizontal astigmatism 61.2%, vertical 2.8% and rest else for 36%. Setting point from Binocular vision tells that average adding power of 40-44 (+0.75D) or (+1.00D), 45-49 (+1.25D) or (+1.50D), 50-54 (+1.50D), 55-59 (+2.00D), 60-64 (+2.50D), 65-69 (+2.50D) or (+2.75D), over $70{\leq}(+3.00D)$ or (+3.25D) of average adding power.

• Journal of Korean Ophthalmic Optics Society
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• v.15 no.3
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• pp.219-225
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• 2010

Purpose: Usefulness in predicting the power of spherical rigid gas-pearmeable (RGP) lenses prescription using dioptric power matrices and arithmetic calculations was evaluated in this study. Noncycloplegic refractive errors and over-refractions were performed on 110 eyes of 55 subjects (36 males and 19 females, aged $24.60{\pm}1.55$years) in twenties objectively with an auto-refractometer (with keratometer) and subjectively. Tear lenses were calculated from keratometric readings and base curves of RGP lenses, and the power of RGP lenses were computed by a dioptric power matrix and an arithmetic calculation from the manifest refraction and the tear lens, and were compared with those by over-refractions in terms of spherical (Sph), spherical quivalent (SE) and astigmatic power. Results: The mean difference (MD) and 95% limits of agreement (LOA=$MD{\pm}1.96SD$) were better for SE (0.26D, $0.26{\pm}0.70D$) than for Sph (0.61D, $0.61{\pm}0.86D$). The mean difference and agreement of the cylindrical power between matrix and arithmetic calculation (-0.13D, $-0.13{\pm}0.53D$) were better than between the others (-0.24D, $0.24{\pm}0.84D$ between matrix and over-refraction; -0.12D, $0.12{\pm}1.00D$ between arithmetic calculation and over-refraction). The fitness of spherical RGP lenses were 54.5% for matrix, 66.4% for arithmetic calculation and 91.8% for over-refraction. Arithmetic calculation was close to the over-refraction. Conclusions: In predicting indications and powers of spherical RGP lens fitting, although there are the differences of axis between total (spectacle) astigmatism and corneal astigmatism, Spherical equivalent using an arithmetic calculation provides a more useful application than using a dioptric power matrix.