• Journal of Korean Ophthalmic Optics Society
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• v.12 no.4
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• pp.55-69
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• 2007

The purpose of this study was to perform a clinical test using ez NANOsence II RGP contact lenses for the effects of visual acuity and cornea on subjects with abnormal refraction status. One hundred twenty one adults (twenty nine males, ninety two females, range = 17 to 43, mean = 22.86) were recorded. The subject's history including, the symptoms from previous lens wear, were studied. The subjects were observed, both pre and post lens wear, for any symptoms and signs of change of the eye. The Visual acuity and the binocular status were tested at the far distance using the contact lens. The refraction test was performed on the naked eye using the objective method (Topcon KR-8100, Japan). The Stereopsis test was performed at the near distance after contact lens wear by the Titmus fly (Stereo Optical Co., U.S.A) and TNO (TECH, The netherlands). The contrast sensitivity diagnosis was performed at 1m distance after contact lens wear by the contrast sensitivity chart (pelli-Robertson, USA). The corneal topography was analyzed on the naked eye after lens wear by ORB scan (Bausch Lomb, U.S.A.). The ultra structure of surface on the contact lens was observed using SEM (JMS-5800, Japan). The chemical component's of the contact lens was analyzed by EDS program. The results of this study were as follows: 1. The longer of contact lens wear period, The subjects have acquired the most improved visual function. 2. Subjects had experienced few side effects wearing the contact lenses. 3. The lenses were easy to use by the subjects. 4. The longer of contact lens wear period, the power of cornea had more decrease. but the base curve of cornea had more increase and corneal astigmatism was decrease (p<0.01). Also, the thickness of corneal center was few decrease. 5. Longer periods of using the contact lens showed stereopsis and contrast sensitivity at more normal values. 6 The corneal topographical after lens wear showed most subjects with similar morphology for different wear periods. 7. The surface ultrastructure of the new and used contact lens was the similar fine shape. 8. The chemical component's of in the new and used contact appeared to have similar results. In conclusion, this study showed that the surface ultrastructure and chemical component's of the new and used contact lens are similar. In addition, the subjects had improved the quality of vision and few experienced any side effects during long periods of contact lens wear. Also they have decrease of corneal astigmatism during the long period of lens wear. Our test has showed that the chemical composition and fine structure of contact lens have related to the visual function on contact lens wearer. In this paper, we suggested that ez NANOsence II RGP contact lenses had a moderate effect for correcting vision of abnormal refraction eye.

• Journal of Korean Ophthalmic Optics Society
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• v.20 no.1
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• pp.43-49
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• 2015

Purpose: This study was to compare the habitual soft contact lens wear to recommended wearing schedule for subjects and suggest a clinical guideline for prescribing contact lens. Methods: 611 adults (39 men and 572 women) with contact lens experience took part in this study. The survey collected information about current wearing schedule (hours/day and days/week), types of lenses worn and awareness of recommended wear schedule. Results: The subjects wore the daily contact lens for $7.97{\pm}3.60$ hours/day in average. Of these, 247 subjects (40.4%) exceeded the recommended wear schedule and 36 (5.9%) wore for over 15 hours. It turned out that subjects with 3-month extended contact lenses and the ones with the conventional daily wear wore for $9.79{\pm}2.68$ hours and $8.98{\pm}3.30$ hours/day, respectively. For subjects wearing contact lenses longer than five days/week it tended to wear for over 9 hours. Those who were aware of the wear schedule were 293 (48.0%), and those not were 318 (52.0%). 56.7% of subjects who were aware of the wear schedule respected the recommendation whereas only 22.3% of those unaware of it were found to respect it. The possibility to respect the wear schedule was 4.55 times higher when wearers were aware of it. Conclusions: Korean office workers wearing contact lenses wore for $7.97{\pm}3.60$ hours/day. 247 (40.4%) of subjects wore contact lens longer than recommended wear schedule. This implies that it will need to educate contact lens wearer about recommended wear schedule and advice for the long time wearer.

• Journal of Korean Ophthalmic Optics Society
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• v.18 no.4
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• pp.449-456
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• 2013

Purpose: The present study aimed to investigate the effects of corneal eccentricity and shape on the rotational pattern of toric soft lens by the postural change of lens wearers. Methods: The corneal eccentricity of 41 eyes (aged 20s) having -1.0 D with-the-rule corneal astigmatism (WRCA) was measured, and then toric soft lenses were fitted with the amount of total astigmatism. In lying and straight postures, the rotation of toric soft lenses was recorded by a camera attached to slitlamp and analyzed. Results: Most toric soft lens designed with accelerated stabilization rotated to the temporal direction, which was the lying position direction, regardless of corneal eccentricity, and some lenses rotated to the nasal direction for high corneal eccentricity and corneal type of asymmetric bowtie. There was no correlation between the amount of rotation and corneal eccentricity right after of contact lens wearing in straight and lying posture, however, the amount of rotation was the greater for the cornea with the higher eccentricity after the subjects laying down for some period. The speed of lens rotation started to decrease after the subjects laying down, but the speed was not different according to corneal eccentricity difference. The amount of lens rotation for symmetric and asymmetric bowtie-typed corneas increased more than it for oval-typed cornea, and it was same even with time elapsing. The speed of lens rotation in lying posture was the slowest in asymmetric bowtie-typed cornea compared with other corneal types. Conclusions: From the present study, it was revealed that the rotational pattern of toric soft lens was affected by corneal eccentricity and corneal shape when the wearer's posture changed. Thus, it should be considered for the development of the fitting guideline and the design of toric soft lens.

• Journal of Korean Ophthalmic Optics Society
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• v.13 no.1
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• pp.95-99
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• 2008

Purpose: Even refractive error is perfectly corrected by glasses power, the glasses wearer can feel imbalance and uncomfortable by prism effects. The purpose of this study was to investigate subjective imbalance to vertical yoked prism in visually normal subjects. Methods: Visually normal 37 subjects (aged 20 to 31 y) were fully corrected by soft contact lens and worn vertical yoked prism, base up and base down 1, 2, 4, 6, 8 prism diopter(pd) at random order. A rating scale questionnaire was administered to assess quantitatively subjective imbalance to the yoked prism. The near phoria tests were done using Howell-Kim phoria card at 40 cm distance. Results: For the subjective response of imbalance, base up yoked prism was higher than base down yoked prism (t-test: t=4.67, p=0.00) in over 2 prism diopters. The frequency of subjects who feel imbalance by base up vertical yoked prism is higher for near esophoric group than for exophoric group. Conclusions: To reduce subjective imbalance caused by glasses such as dizzy, it needs to make the minimum prism effect, and base down yoked prism is more effective than base up yoked prism in prism effects.