• Journal of Korean Ophthalmic Optics Society
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• v.19 no.2
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• pp.261-270
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• 2014

Purpose: To study the effect of an artificially induced dioptric blur on acuity and contrast sensitivity using the $Optec^{(R)}$ 6500. Methods: Healthy 31 subjects aged $22.90{\pm}1.92$ (male 16, female 15) who were recruited from university students with 6/6 (20/20) or better corrected visual acuity and normal binocularity. They were measured objective and subjective refraction for full correction and dioptric blur using 0.00 ~ +3.00 D (+0.50 D steps) trial lenses and trial frame. They were measured binocularly visual acuity and contrast sensitivity with the $Optec^{(R)}$ 6500 (Stereo Optical Co., Inc., Chicago, Illinois, USA) under day conditions (photopic condition, $85cd/m^2$). Results: The higher dioptric blur, the less distance visual acuity and decrease rate of visual acuity. The higher dioptric blur, the less contrast sensitivity at all frequencies, and the peak of contrast sensitivity was shifted from middle frequency (6 cpd) to low frequency (1.5 cpd). When the visual acuity was best visual acuity to 0.77, there was the peak point at 6 cpd which was normal contrast sensitivity peak point. Conclusions: If the low refractive error is uncorrected or the refractive error is inappropriate, the contrast sensitivity is decreased and the peak point of contrast sensitivity frequency is shifted abnormally though small uncorrected refractive error. So it will be considered that regular eye test and decision of refractive error correction is important.

• Journal of Korean Ophthalmic Optics Society
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• v.12 no.4
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• pp.119-125
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• 2007

The aim of the present study was to compare the contrast sensitivity of soft contact lens wearers, spectacle wearers or emmetropia. Seventy myopic eyes and thirty emmetropic eyes aged 19 to 26 years were collected. The myopic group included 48 eyes corrected with spectacle lenses and 22 eyes of them corrected with contact lenses, too: all had corrected vision acuity of 20/20 or better. Spatial contrast sensitivity was measured using the OPTEC 6500 contrast sensitivity view-in tester included the EyeView　 Functional Vision Analysis software at photopic or mesoopic condition. There was no significant difference in contrast sensitivity between spectacle lenses and emmetropes. Myopes corrected with soft contact lenses showed statistical sensitivity losses at 1.5, 12 cycle/degree spatial frequencies. In conclusion, our findings suggest that loss of contrast sensitivity in soft contact lens wearers might be interpreted as evidence for corneal disruption before corneal pathological events occur in contact lens wearers. Contrast sensitivity testing appears to be a useful method for evaluating soft contact lenses.

• Journal of Korean Ophthalmic Optics Society
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• v.20 no.3
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• pp.355-362
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• 2015

Purpose: To investigate the effects of the transmittance of diffusive blurson visual acuity and contrast sensitivity. Methods: Visual acuity and contrast sensitivity were measured by using Optec$^{(R)}$ 6500 in Healthy 30 subjects aged $22.83{\pm}0.50$ (male 13, female 17) who were recruited from university students. Cataract simulator was used as a tool for diffusive blur. Visual acuity and contrast sensitivity were measured with varying the transmittance of diffusive blur in order to simulate progression of cataract and concentration in fog. Results: Visual acuity was reduced proportionally with decreasing the transmittance of the diffusive blur as follows: $VA(T)=1.84{\times}10^{-2}T-0.645$. Contrast sensitivity was decreased in all spatial frequencies. Contrast sensitivity in a high spatial frequency band was a greater effect and was off the normal range of contrast sensitivity. The peak of contrast sensitivity was moved in the direction to low frequency. From an intersection point of contrast sensitivity function, we could calculated the transmittance of the diffusive blur being off the normal range and the shift to peak spatial frequency. The peak of contrast sensitivity function was observed to move from 6 to 3 cpd at transmittance of about 78.70%, the contrast sensitivities for all frequencies at transmittance of about 69.71% were deviated from the normal range. Conclusions: The transmittance of diffusive blur causes a reduction in visual acuity and contrast sensitivity, a deviation of normal range of contrast sensitivity, and a shift of peak contrast sensitivity. Therefore the more attention is required when suffering from cataracts or driving in fog.

• Journal of Korean Ophthalmic Optics Society
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• v.14 no.1
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• pp.39-45
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• 2009

Purpose: The purpose of this study is to compare the visual performance by contrast sensitivity (CS) and disability glare (DG) in low astigmatic eyes corrected with toric soft lenses and other optical corrections. Methods: Twenty university students with myopia (-1.00 to -6.50D Sph. with astigmatism up to 1.50 cyl) were enrolled and corrected by five different methods: 1) soft toric lenses; 2) spherical soft contact lenses; 3) RGP lenses; 4) best spectacle corrected visual acuity; 5) spherical equivalent spectacles. All subjects had corrected vision acuity of 20/20 or better. Contrast sensitivity and disability glare were measured using the OPTEC 6500 contrast sensitivity view-in tester included the EyeView Functional Vision Analysis software at photopic or mesopic conditions with glare. Results: At photopic condition, best corrected spectacle wearers had the highest monocular contrast sensitivity at all spatial frequency followed by soft toric lenses, RGP lenses, spherical equivalent spectacles, and spherical soft contact lenses. However, all of them were in normal contrast sensitivity value at photopic condition. At mesopic condition with glare, toric soft lenses were the highest and followed by RGP lenses, spherical equivalent spectacles, best spectacle corrected visual acuity and spherical soft contact lenses. It was observed that spherical soft contact lens wearers demonstrated lower range than normal contrast sensitivity value at mesopic condition with glare. Conclusion: Toric soft lenses gave better visual performance than spherical soft lenses in low astigmatic eyes. Subjects requiring the use of contact lenses under mesophic conditions could benefit from toric soft lenses.

• Journal of Korean Ophthalmic Optics Society
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• v.17 no.4
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• pp.365-372
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• 2012

Purpose: To investigate ocular higher order aberrations (HOA) and spherical aberration changes caused by an aspheric soft contact lens designed to reduce spherical aberration (SA) of the eye. Methods: Fifty subjects who have successfully experienced soft contact lenses were refitted with aspheric design (Soflens Daily Disposable: SDD, Bausch+Lomb) soft contact lens. Ocular higher order aberrations (HOA) and stand alone SA were measured and analyzed for a 4-mm pupil size using Wave-Scan Wavefront$^{TM}$ aberrometer (VISX, Santa Clara, CA, USA). High and low contrast log MAR visual acuity and contrast sensitivity function (CSF) were also measured under photopic and mesopic conditions (OPTEC 6500 Vision Tester$^{(R)}$). All measurements were conducted monocularly with an undilated pupil. Results: The RMS mean values for total HOA with SDD contact lenses were significantly lower than those at with unaided eyes (p<0.001) and a reduction for SA in the SDD was close to the baseline SA (zero ${\mu}m$) (p<0.001). For the SDD lens, there was a statistically significant correlation between the changes in the total HOA and the contact lens power (r=0.237, p=0.018) as well as between the changes in SA and the lens power (r=0.324, p=0.001). High contrast visual acuity (HCVA) and low contrast visual acuity (LCVA) with SDD lenses were $-0.063{\pm}0.062$ and $0.119{\pm}0.060$, respectively under photopic and $-0.003{\pm}0.063$ and $0.198{\pm}0.067$, respectively under mesopic condition. Contrast Sensitivity Function (CSF) with SDD lenses under both photopic and mesopic conditions was $3.095{\pm}0.068$ and $3.087{\pm}0.074$, respectively. Conclusions: The SDD contact lens designed to control SA reduced the total ocular HOA and SA of the eye, resulting in compensating for positive SA of the eyes. Thus, the optical benefits of the lens with SA control would be adopted for improving the quality of vision.