• Journal of Korean Ophthalmic Optics Society
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• v.11 no.4
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• pp.293-298
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• 2006

For this study, Clinical evaluation of the diverse Autorefractors was performed to examine validity and repeatability compared with subjective refraction. Measurements of refractive error were performed on 212 eyes of 106 subjects subjectivly noncycloplegic. Intersession repeatability of the Autorefractors were also assessed on all 106 subjects together with intersession repeatability on 7 to 14 days intervals. Spherical powers of subjective refraction and autorefractions by Autorefractors were analyzed by paired T-test.

• Journal of Korean Ophthalmic Optics Society
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• v.11 no.1
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• pp.63-69
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• 2006

Clinical evaluation by Astigmatic Components of autorefractors was performed to examine validity and accuracy compared with subjective refraction. The mean cylindrical powers of Astigmatic Components of Subjective Refraction, Closed-view and Open-view were found to be $-0.689{\pm}0.516D$, $-0.691{\pm}0.530D$, $-0.470{\pm}0.507D$, respectively. The Difference of cylindrical Components between Subjective Refraction and Closed, Open-view were found to be $0.002{\pm}0.191D$, $0.015{\pm}0.137D$, respectively. Approximately 85% of Closed-view and Open-view autorefractor measurements were within ${\pm}20^{\circ}$ range of the difference of cylindrical axis with subjective refraction. The mean $J_0$ Components of Astigmatic Components of subjective refraction, Closed-view and Open-view were found to be $-0.155{\pm}0.332D$, $-0.004{\pm}0.178D$, $-0.001{\pm}0.156D$, respectively. The mean $J_{45}$ Components of Astigmatic Components, Closed-view and Open-view were found to be $-0.023{\pm}0.227D$, $-0.026{\pm}0.172D$, $-0.014{\pm}0.182D$, respectively. Both of the Closed-view and Open-view refractor showed available accuracy in measuring astigmatic components.

• Journal of Korean Ophthalmic Optics Society
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• v.11 no.1
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• pp.55-62
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• 2006

Clinical evaluation of the Closed-view autorefractor and Open-view autorefractor was performed to examine validity and repeatability compared with subjective refraction. Measurements of refractive error were performed on 126 eyes of 65 subjects (aged $26{\pm}7.5$ years) subjectively noncycloplegic. Intersession repeatability of the Closed-view and Open-view were also assessed on all 65 subjects together with Intersession repeatability on 7 to 14 days intervals. Spherical powers and spherical equivalent values of subjective refraction and autorefractions by Closed-view and Open-view were analyzed by paired T-test. The mean spherical powers of subjective refraction, Closed-view and Open-view were determined to be $-2.125{\pm}2.155D$, $-2.146{\pm}1.907D$, $-2.117{\pm}2.121D$, respectively. The mean spherical equivalent values of subjective refraction, Closed-view and Open-view were determined to be $-2.362{\pm}2.204D$, $-2.391{\pm}1.967D$, $-2.366{\pm}2.162D$, respectively. The results showed that the refractive errors as measured by the Closed-view and Open-view were found to be similar to the subjective refraction in all components.

• The Korean Journal of Vision Science
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• v.20 no.4
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• pp.443-451
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• 2018

Purpose : To find out the reliability of autorefractometer after laser refractive surgery Methods : We measured and compared spherical and cylinder powers of those undergone LASEK surgery with 1.0 of naked vision after at least 3 months of the surgery with an autorefractometer(CANON Full Auto Ref-Keratometer RK-F1, Japan) and a retinoscope(Streak Retinoscope 18200, WelchAllyn, USA), and also applied spherical equivalent powers. The refractive status before surgery was divided into high, medium, and low myopia according to the results measured using an autorefractometer, and then analyzed again the reliability of the autorefractometer after surgery according to the preoperative refractive status. The agreement of two methods was identified using Bland-Altman(Bland-Altman limits of agreement(LoA)). Results : After the surgery, when comparing spherical, cylinder and equivalent powers in the whole data measured by autorefractometry and retinoscopy significant differences were found(p<0.01). According to the degree of refractive errors, all sort of refractive errors was shown significantly different(p<0.01) except for cylinder power of the medium myopia. In general, the refractive errors especially spherical and spherical equivalent powers by autorefractometry were shown a myopic trend from -0.38 D to -0.53 D. On the other hand, it was shown a hyperopic trend of approximately +0.30 D using retinoscopy. In comparison of two objective refractions, it was shown a myopic trend as $-0.51{\pm}0.45D$(LoA +0.36 D ~ -1.39 D) and compatible. Conclusion : Even though it would be positive in terms of compatibility of the methods, it is necessary that the glasses should be prescribed by subjective refraction since autorefractometry is shown myopic in those undergone the surgery and suffering from myopic regression.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.8
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• pp.353-359
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• 2018

In this study, the performance between subjective refraction and open-field/closed view autorefraction was estimated. We measured the refractive error of early adults aged 18 to 20 years who did not have eye disease. The differences between measurements obtained by subjective refraction and open-field autorefraction for SE, J0, and J45 were $-0.13{\pm}0.53D$ (p=0.17), $+0.33{\pm}0.68D$ (p=0.01), and $+0.13{\pm}0.68D$ (p=0.26), respectively, with only J0 differing significantly. The differences between the measurements of subjective refraction and closed-view autorefraction for SE, J0, and J45 were $-0.30{\pm}0.42D$ (p=0.00), $+0.30{\pm}0.71D$ (p=0.02), and $-0.02{\pm}0.63D$ (p=0.88), respectively, with only SE and J0 differing significantly. The coefficient of accuracy for SE, J0, and J45 components of open-field and closed-view autorefraction were 1.04, 1.33, and 1.34 and 0.83, 1.40, and 1.24, respectively. It is possible to predict the refractive error, which is necessary when deciding on subjective refraction, by measuring the objective refraction of open-field/closed view autorefractors.

• Journal of Korean Ophthalmic Optics Society
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• v.9 no.2
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• pp.323-332
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• 2004

This study researched the visual acuity test object and Auto-refractormeter, visual of near power. The object were composed of middle aged, the old men and women who in habit Daegu. The results were as follows : 1. The subjects consisted of 537 people, 29.98% men, 70.02% women. 2. The emmetropia was 1.12% for myopia, 2.79% for hyperopia, 96.09% for astigmatism. 3. The abnormal refraction was composition for myopic compound astigmatism(16.57%), hyperopia compound astigmatism(45.62%), Mixed astigmatism(33.89%). 4. On the Myopic Spherical Equivalent(S.E) power, the range of -0.50D ${\leq}$ M.S.E < -1.00D was 21.67%, -1.00D ${\leq}$ M.S.E < -2.00D was 48.89%, -2.00D ${\leq}$ M.S.E < -6.00D was 29.44%. 5. On the Hyperopic Spherical Equivalent(S.E) power, the range of +0.50D ${\leq}$ H.S.E < +1.00D was 28.57%, +1.00D ${\leq}$ H.S.E < +2.00D was 49.30%, +2.00D ${\leq}$ H.S.E < +6.00D was 23.13%. 6. The addition power was 1.00D(8.01%), 1.50D(8.57%), 2.00D(13.78%), 2.50D(16.57%), 3.00D(16.95%), 3.50D(17.88%), 4.00D(18.25%).

• Journal of Korean Ophthalmic Optics Society
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• v.17 no.3
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• pp.293-298
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• 2012

Purpose: We compared static retinoscopy in eyes opened with cycloplegic refraction depending on the hyperopia for school-aged children. Methods: There were 59 eyes (30 patients) who were divided into 3 groups - the mild hyperopia (+0.25 D ~ +1.00 D), moderate hyperopia (+1.25 D ~ +2.00 D) and high hyperopia (+2.25 D or more). They all had 0.8 visual acuity or more. Autorefraction and retinoscopy were performed prior to cycloplegic refraction, and then copmared with manifest refraction and cycloplegic refraction. Results: Hyperopia measured with static retinoscopy tends to be measured higher than manifest refraction for school-aged children. Changes of spherical power was statistically significant (p < 0.001). Changes of astigmatism was not statistically significant (p > 0.05). Conclusions: The difference between cycloplegic refraction and static retinoscopy was not significant for hyperopic school-aged children. The use of retinoscopy was limited for opticians because of legal constraints. The usage of static retinoscopy in eyes opened for optician should be generalized under the conditions not using the cycloplegic.

• Journal of Korean Ophthalmic Optics Society
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• v.7 no.2
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• pp.203-207
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• 2002

In this study, by using the eye model of NAVARRO, KOOIJMAN, MAHKICHOONG, the properties of optical system are reserched in a finite ray tracing method, when ametropia is corrected by glasses or contact lens, this study is useful as a reference. Also, when Auto-refractometer for refraction test and Keratomeler are designed, these eye models can be used.

• Journal of Korean Ophthalmic Optics Society
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• v.12 no.2
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• pp.25-36
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• 2007

We researched the change of astigmatism power when the fixation point moved from far distance to near distance. Astigmatism power was measured by using both eyes open-view auto-refractometer. We divided the ages between 5 and 67 years old into 12 groups with 1,598 healthy eyes(male-698 eyes and female-900 eyes) without eyes problems and experiences of eyes operations. The mean power in far astigmatism showed that with-the-rule of the total astigmatism: -0.79D, with-the-rule of the corneal astigmatism: -1.07D and against-the-rule of the residual astigmatism : -0.79D were found most respectively. The correlation between cornea astigmatism and total astigmatism was y=0.7493 x + 0.5661 r=0.6510, residual astigmatism and total astigmatism was y=0.248 x - 0.5926 r=0.2598 and corneal astigmatism and residual astigmatism was y=-0.4439 x - 0.1813 r=-0.5551 in the far distance. The mean power in near astigmatism showed that with-the-rule of total astigmatism : -0.92D, with-the-rule of corneal astigmatism : -1.12D, against-the-rule of residual astigmatism : -0.87D were found most respectively. In the near distance, The correlation between corneal astigmatism and total astigmatism was y=0.6872 x + 0.5934 r=0.6204, residual astigmatism and total astigmatism was y=0.303 x - 0.6066 r=0.3165, corneal astigmatism and residual astigmatism was y=-0.46 x - 0.0626 r=-0.5322. When the fixation point moved far distance to near distance, the differences of power according to the type of astigmatism were total astigmatism: $-0.07D{\pm}0.44D$, corneal astigmatism: $-0.04D{\pm}0.54D$ residual astigmatism:$0.01D{\pm}0.53D$. Most of astigmatism refractive power was increased except for oblique-the -astigmatism. When the fixation point moved far distance to near distance, the change of astigmatism refractive power showed total astigmatism: 540 eyes(33.7%), corneal astigmatism: 638 eyes(39.9%), residual: 841 eyes(52.6%).