• Journal of Korean Ophthalmic Optics Society
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• v.19 no.1
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• pp.31-42
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• 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
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• v.18 no.1
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• pp.27-35
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• 2013

Purpose: The present study was conducted to investigate the changes in the physical properties of RGP lenses induced by the polishing during the process of RGP lens manufacturing, and further evaluate the differences in the actual wearer's comfort and the tear film break-up time caused by these changes. Methods: RGP lenses (fluorosilicone acrylate material) were divided into 4 groups by the different lens-polishing time like 0, 25, 50 and 100 seconds and the thickness, the surface roughness and the wetting angle of those lenses were compared. Furthermore, the comfortability of the lens wear was surveyed after applying these lenses on the subject's eyes with normal tear volume and the non-invasive tear break-up time of the wearers was measured. Results: The central thickness of 4 RGP lenses made of different lens-polishing time was not significantly different however, the lens surface was changed smoother after polishing to be confirmed by scanning electron microscopy. The wetting angle of the RGP lens significantly decreased in accordance with the increase of polishing time. Thus, the difference of approximately $16^{\circ}$ between 0 second and 100 seconds-polishing was statistically significant. The actual wearing feeling of RGP lens was tended to improve in accordance with the increase of the lens wettability however, it was not proportional improvement. The non-invasive tear break-up time of the lens wearers showed different aspect compared with the changes in lens wettability and the actual feeling of RGP lens wear. Conclusions: In this study, better lens wettability, thinner lens thickness, and/or improved lens surface induced by physical stimuli in the process of RGP lens manufacturing was not well-correlated with the increase of actual subjective/objective satisfaction in RGP lens wear. Thus, the consideration of physical properties of the lens as well as the lens wearers' physiological factors in the process of RGP lens manufacturing may be suggested.