• Journal of the Korea society of information convergence
• /
• v.5 no.2
• /
• pp.77-83
• /
• 2012

This study was cosmetic contact lens wear for up to 2 weeks in for the evaluation of the insertion. In 1 week during weeks 1 and 2 has been rated 'positive' or 'insert' easy insertion and removal of lenses in the mirror when I saw the 'red eye' negative 'rating in 18 patients (45 %), in 2 shown in 14 patients (35%) as a 'negative' rating over time, depending on the awareness hyperemia has been reduced could see. Future lens purchases from doctors' Week 1 at the 2nd week, came as a result of the positive> negative evaluation was positive = negative. Rating, but usually more than 1 week, 2 weeks, 26 patients (65%) showed no change. State upon insertion of sight, wearing period increased dryness and showed a more positive assessment, the Comfort showed similar ratings. Somewhat negative assessment upon removal of vision status, comfort, dryness, day-to-day life at present, but in both state vision, comfort, dryness positive assessment appears worn than when a positive evaluation appears was unknown.

• Journal of the Korean Chemical Society
• /
• v.55 no.2
• /
• pp.283-289
• /
• 2011

This study used glycerol dimethacrylate with the cross-linker EGDMA (ethylene glycol dimethacrylate), HEMA (2-hydroxyethyl methacrylate), MMA (methyl methacrylate), MA (methacrylic acid) and the initiator AIBN (azobisisobutyronitrile) for copolymerization. Measurement of the physical properties of the copolymerized polymer showed that the water content was 22~32%, refractive index was 1.442~1.463 and visible ray transmittance 90.0~90.5% while the contact angle showed a distribution between 56 and $65^{\circ}$. Also, the measurement showed that the decreased amount of contact angle of the copolymer measured using the sessile drop method ranged between $9.89^{\circ}$ and $18.99^{\circ}$ with increase of glycerol dimethacrylate. Based on the results of this study, the produced copolymer is suitable for use as a material to high wettability ophthalmic lenses.

• Journal of Korean Ophthalmic Optics Society
• /
• v.19 no.1
• /
• pp.31-42
• /
• 2014

Purpose: The present study was conducted to investigate the effect of the physical properties of RGP lens induced by lens polishing on the actual wearer's subjective comfort, the tear film break-up time and the blinking rate as a follow-up study that revealed the relationship between the lens physical properties during lens manufacturing and lens wearer's factors. Methods: RGP lenses made from the three different polishing conditions (25, 50 and 100 seconds) were applied on 28 eyes of 17 subjects, aged 20 to 29 years, without any known disease and surgical history in the eyes. While the subjects were asked to wear the RGP lenses longer than a week, the questionnaire for the comfortability was administered everyday. Subjective and objective tear break-up time and blinking rate of the wearers were further measured. Results: The wearer's subjective comfortability showed some difference in the type of discomfort and satisfaction score according to the polishing status when wearing RGP lenses made from different polishing conditions longer than a week, and a bigger difference in satisfaction score induced by polishing condition was especially shown in experienced RGP lens wearer rather than un-experienced wearer. In the case of RGP lens wearer compared with the ones without the wearing experience, as the wearing time increased subjective and objective tear break-up time were increased and the blinking rate was decreased. However, subjective and objective tear break-up time were tended to decrease with even longer wearing time when wearing the RGP lens made from the polishment for 100 seconds. Conclusions: These results confirmed that the optimization of physical properties of the lens may not give the same effect on the wearer's subjective and objective symptoms and other factors when actual wearing. From the results, it can suggest that the success rate of RGP lens wear may be changed by physiological factors such as the stabilization of wearer's tear film, comfortability and lens wearing experience when wearing RGP lens based on 'The manufacturing standard for soft contact lens/hard contact lens' provided by Korea Food and Drug Administration.

• Journal of Korean Ophthalmic Optics Society
• /
• v.13 no.4
• /
• pp.51-58
• /
• 2008

Purpose: This study was assessed to investigate adverse effect induced by overuse of disposable soft contact lenses (CL). Methods: Three disposable lenses (etafilcon A, hilabilcon A, and nelfilcon A) were applied to 19 normal subjects free from any eye diseases for either a single day or variable periods by when subjects complained any discomforts. On the first and last days, localizations of lens' center on corneal surface and blink rates were recorded at every case. Results: Among CL wearers, 10.5% and 47.4% of total subjects quit wearing on the second day and third day, respectively. The case of stopping disposable lens wear was continuously increased with extended hour of lens application. On fourth day, 70.2% of CL wearers reported severe discomforts such as redness, dryness, irritation, pain and blurred vision. When subjects stopped CL wear, decentration of lens from the center of cornea was observed when it compared to the case of single usage of disposable CL. Also about 80% of total subjects showed increased blink rate when CL were worn for more than 2 days. These changes in lens centration and blink rate were consistantly shown regardless of lens types. Conclusions: Blurred vision and acute/chronic discomforts could occur to CL wearers by decentration of lens and increased blink rate when CL were overused more than 2 days even the numbers of two parameters measured in this study were variable by each subject or lens types. Therefore, consideration of individual characteristics and lens types is critical to prevent adverse effects may induced by overusage of disposable lens.

• Journal of Korean Ophthalmic Optics Society
• /
• v.18 no.4
• /
• pp.429-439
• /
• 2013

Purpose: This study was assessed to investigate the change of subjective and/or objective symptoms and the light transmissibility of lens caused by over-usage of daily disposable circle contact lenses (circle lens). Methods: Three daily disposable circle lenses made of etafilcon A, hilafilcon B, and nelfilcon A were applied on 20 normal eyes free from any eye diseases by when subjects complained any kind of discomfort. On the first and the last days of lens wearing, subjective discomfort, blinking rate, non-invasive break-up time, lens centration on corneal surface and visible light transmissibility of lens were recorded at every case and compared. Results: The circle lens wearers complained discomfort when they wore the circle lens more than 15 hours, in excess of 8 hours being the recommended wearing time and the most circle lens wearers quit the lens wearing when they wore more than 30 hours. On the last day of lens wearing, the representative subjective discomforts were stiffness, dryness and tiredness. When the subjects wore circle lens more than the recommended time, a tendency of increased blinking rate and decreased NIBUT was observed when it compared with the values right after lens wearing. On the last day of lens wearing, the lens centration was shown to be decentrated from the pupil center compared with the centration right after the wearing. These changes in lens centration and blinking rate were consistently shown in all cases of lens wearing however, the difference in the degree of subjective and/or objective change was present depending on lens materials and subjects. The visible light transmissibility of circle lens has largely been changed. Conclusions: From these results, it was thought that the decreased NIBUT induced dryness and stiffness and decreased visible light transmissibility caused more blinking when daily disposable circle lens was exceedingly used, which provoked lens decentration and subjective discomfort. However, the difference of subjective and/or objective change was largely varied in accordance with the lens material types and individuality and thus it may occur some unexpected problems by the individual base. Therefore, the education about the necessity to comply with the recommended wearing time and the problem will be essential.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.14 no.6
• /
• pp.2839-2843
• /
• 2013

In this study, the relation between the corneal refractive power and the tear break-up time(TBUT) was analyzed. The results can be effectively used in eye clinics and served as the reference on wearing the contact lenses. We had measured the radius of the corneal of university students who are in the range of 21 to 27 year-old and who don't have eye disease. The corneal refractive power was calculated by using the radius of the corneal. And TBUT is the time when the mire image is distorted first time. The relation between the corneal refractive power and TBUT in right eye was a linear as 'y=37.921-0.610x', in which the larger the refractive power of the cornea is, the shorter TBUT is(negative relationship; r=-0.462, p=0.010). The relation in left eye was also a negatively linear as 'y=41.894-0.695x'(r=-0.509, p=0.004). Consequently, in both eyes the corneal refractive power and TBUT have a negative correlation when myopia is a high. It is possible to predict TBUT, which is necessary in deciding on wear of contact lenses, by measuring the corneal radius of subjects.

• Journal of Korean Ophthalmic Optics Society
• /
• v.5 no.2
• /
• pp.107-113
• /
• 2000

This study has analyzed soft contact lens care-after-sale and periodic examinations at optical shops and eye clinics. And I wish to make that use of educational data for the soft contact lens lesson of the department of ocular optics. This questionnaire studied the status of care for soft contact lens and periodic examination, of students who wears soft contact lens. The results are as follows: First, 7.5% of students questioned wore soft contact lens. More women than men wore soft contact lens. The soft contact lens wearers purchased lens mainly at optical shops. 78.5% of them wore daily wear lens. Because of cosmetic advantages of soft contact lens. 47.9% of them wore soft contact lens. 72.5% of them wore soft contact lens less than 12 hours per a day. 32.0% of them has worn soft contact lens more than 6 months less than 1 year. 51.1% of them experienced irritation. 39.7% of them have exchanged soft contact lens between 6 and 9 months. Secondly, when purchasing lenses. 60% of soft contact lens wearers were given instructions of general care, such as duration of wearing lens, how to remove protein, how to store, and how to sterilize at both of eye clinics and optical shops. But the proportion of instructions, such as side effects and periodic examination which were given to soft contact lens wearers, is lower both at eye clinics and optical shops. Especially at optical shops, the proportion of instruction for periodic examination, is lower than at eye clinics(p<0.05). Thirdly, The proportion of operations of periodic examinations after use of soft contact lens both at eye clinics and optical shops, is low. The soft contact lens wearers have had more periodic examinations at eye clinics than at optical shops. But the rate of non-periodic examination at optical shop is 87.9%. And for periodic examinations, general care was done at optical shops. On the other hand, eye examinations, general care, and treatments were done more at eye clinics. Fourthly, 60.3% of the soft contact lens wearers understood the necessity of the periodic examinations, but actually, only 6.4% of them were given the schedule for the periodic examinations, and 2.5% of them were given at an optical shop(p<0.01).

• Journal of Korean Ophthalmic Optics Society
• /
• v.11 no.3
• /
• pp.173-179
• /
• 2006

We investigated the change of the blink rate by wearing soft contact lens(SCL). Eight types of soft contact lenses were worn by twelve asymptomatic contact lens wearers. When wearers were worn SCLs for 15 min, the average blink rate was 20.0 blinks/min, which was a statistically significant increase compared to 13.3 blinks/min, the average blink rate of non-SCL-worn eye. After 8 hr of lens wear, the average blink rate was 24.3 blinks/min, and it was 11 blinks/min more than that of non-SCL-worn eye and 4 blinks/min more than that of 15 min SCL-worn eye. There were a little difference of the blink rate in types of lens, which the blink rate range of all lens after 15 min of lens wear was 18.1~20.9 blinks/min and that after 8 hr of lens wear was 22.9~24.9 blinks/min. When wearing A lens(vifilcon, 0.06 mm) having thin center thickness, wearers showing difference of 10.0~11.9 blinks/min between non-SCL-worn eye and 15 min SCL-worn eye reached 16.7% and it was more than that of relatively thick B lens(0.17 mm) and C lens(0.14 mm). This result suggest that the center thickness was not unique factor of the blink rate change and other factors would have synthetically influence on the blink rate change. In the case of B lens and C lens of hilafilcon material but having different center thickness and water content, wearers increasing more than 4.0 blinks/min after 8 hr of lens wear was 58.3% and 41.7%, respectively. This result have provided information that the lenses of similar materials but different center thickness and water content could cause individually the different change of the blink rate.

• Journal of Korean Ophthalmic Optics Society
• /
• v.20 no.2
• /
• pp.141-150
• /
• 2015

Purpose: In the present study, a difference in tear volume between the cornea and the rigid gas permeable (RGP) lens relative to corneal shape and corneal astigmatism was investigated by the alignment fitting status of spherical and aspherical RGP lenses. Methods: Spherical and aspherical RGP lenses were fitted with alignment in 77 subjects (135 eyes) who were in their 20~30s. Tear volume stained with fluorescein was qualitatively analyzed by dividing cornea into center, mid-peripheral and peripheral parts. Results: For the spherical RGP lens fitting, tear volume differences were found in each part in all corneal types. For the aspherical RGP lens fitting, tear volume differences were in each corneal part in symmetric bow tie- and asymmetric bow tie-type corneas. However, the tear was equally distributed from the center to the peripheral part in round- and oval-type corneas. In the group with corneal astigmatism lower than 1.25 D, tear volume between center and peripheral parts, and mid-peripheral and peripheral parts, was different when a spherical RGP lens was fitted. However, tear volume in each part was not different in the group with corneal astigmatism over 1.50 D. Moreover, the tear volumes of the central and mid-peripheral parts were proportionally increased with increasing corneal astigmatism in both spherical and aspherical RGP lenses. Furthermore, aspherical RGP lenses showed greater increments than spherical RGP lenses. Conclusions: The results revealed that the difference in tear volume between aspherical RGP lens and cornea was less than spherical RGP lens, and the difference in tear volume varied according to corneal shape and astigmatism. In addition, the method of measuring relative tear volume between RGP lens and cornea that was established in the present study can be used to evaluate tear volume between contact lens and cornea.

• Journal of Korean Ophthalmic Optics Society
• /
• v.12 no.3
• /
• pp.7-17
• /
• 2007

There has been an increase in rigid gas permeable contact lens prescription by the optometrists in Korea since 1995. Therefore, the aim of our study was to find out which equipment is needed for adequate RGP contact lens prescription and the level of the clinical knowledge that they have and the level of education for the patient, to seize about the extended lens education programmes for the Korean optometrist. Also, we tried to figure out the problem that they had in the RGP contact lens prescription, to develope the educational programs for students and to improve legal uncertainties, through this research. The result came out with the following through questionnaires of 400 male and female opticians who is in clinical field. The distributions of respondents are 270 male (67.5%), 130 female (32.5%), and 356 optometry major (89%). We found out the optometry-majored people had faster clinical lens prescriptions (p=0.000), 72.5% of opticians prescribe the RGP-Lenses, and 27.5% do not because of laking in experience (P=0.000). They responded that they need slit-lamp, button lamp, fluorescein dry paper, and etc,for prescription or fitting test. In regular-check-up (Follow-up), the result came out very low by 83% of respondents who are not getting it regularly. And 83.5% (334 people) of them wanted to have those Extended Educational Programs and also the Clinical Education Programs.