• Korean Journal of Optics and Photonics
• /
• v.24 no.5
• /
• pp.217-223
• /
• 2013

White light MTF(Modulation Transter Function)s of biconvex trial lenses from 10 to 20 diopter (D) were represented as a function of angular frequency and visual acuity, and then they were compared with AIM(Aerial Image Modulation) curves. All of the biconvex trial lenses evaluated in on-axis mode had MTF performance that could resolve Landolt's ring up to visual acuity 2.0. However, in a half field angle of five degrees, the trial lens of 10 diopters was able to resolve Landolt's ring up to visual acuity 0.9, and that of 20 diopter only up to visual acuity 0.8. This means that the trial lenses in the case of a half field angle of five degrees do not have sufficient resolution to measure visual acuity by 1.0.

• Journal of Korean Ophthalmic Optics Society
• /
• v.11 no.1
• /
• pp.17-26
• /
• 2006

Video display units (VDU) are interfaces between computers and human operators. This study was performed to have a good understanding of the potential causes of eye problems in 50 students to enable them to perform an accurate assessment of the patient's visual performance while looking at a computer screen. The TSS Optometric Toolkit for Computer Users provides a powerful set of tools to enable eye care practitioners to assess visual performance under conditions that closely simulate a computer user's normal working conditions. The program consists of seven tests: Near vision chart, Sample text display, Spreadsheet display, Fixation disparity, Duochrome, Number search, Randolt Ring search. The results of this study show that 55% of the subjects do not have computer-related eye problems. It is apparent from this data that approximately 25% of all computer-related eye problems are attributable to the display screen, the workstation or inappropriate workpractices. Of the remaining cases, 20% of them will require general purpose spectacles and spectacles specifically for work at the computer. This study suggests that computer program, The TSS Optometric Toolkit for Computer Users, is very useful for assessment of computer-related eye problems.