No abstract

The aim of this study was to survey the presenting visual acuity (VA) and satisfaction of VA tests in health checkups and to suggest ways in which eye care can be improved. VA data were obtained from the results of the health checkups for Korean adults in 2002-2007. Satisfaction questionnaires were administered via direct interview with 173 participants who had health checkups. The prevalence of VA 0.5-1.4 was 76.24%. Women had a higher prevalence than men below VA 0.9 and men had a higher prevalence than women above VA 1.0. The change in VA with age had a tendency to decrease after forties. Findings for satisfaction of VA tests on health checkups showed a level of neutral agreement. In order to enhance satisfaction, it is important that vision testing should provide examinees with referral criterion and follow-up VA results. It is also necessary to have comprehensive eye examination and utilize optometric instruments and professional examiners.

In this study, we have prepared plastic lenses with both photochromic and hard properties by hard coating, and evaluated their optical properties and surface characteristics. Photochromic effects could be observed on the UV spectra of the closed forms and the visible spectra of the open forms. Visible light transmittance of photochromic lenses was from 83.44% for graphite(GP) to 85.15% for blue(BL) in colourless state and from 71.10% for red(RE) to 79.98% for yellow(YE) in colour state. Red photochromic lens was higher in optical density(∆OD) and color difference(△E * ab) than the others. Photochromic lenses applied by hard coating showed good adhesion, hot water resistance, chemical resistance and surface appearance. Also, compared to the uncoated lens, hardness and abrasion resistance were increased. Consequently, this coating system could impart functional properties such as photochromic and hard coating property onto ophthalmic lenses.

The oxygen permeability of a soft contact lens is an important parameter for determining corneal health when considering the physiological response of the eye. The aim of this study is to evaluate the oxygen permeability of soft contact lenses based on thickness, using the polarographic method. The thickness of lens was measured using contact and non-contact method. To assess accuracy and reliability, the Bland-Altman plot was used. The reliability was high for the oxygen permeability based on center thickness measured by contact method, whereas the accuracy was high for the oxygen permeability based on center thickness measured by non-contact method. These results indicate that the permeability characteristics were variable according to the measurement and criteria of thickness of soft contact lenses and the measurement of soft contact lenses by non-contact method was more reasonable. Thus, contact lens practitioners should consider some basic differences between methodologies when interpreting or quoting oxygen performance data.