Purpose: Aims of this study were to investigate the agreement and test-retest repeatability of two methods for measuring magnitude of soft toric lens rotation. The two methods assessed were a newly developed mobile application for iPhone which uses the built-in camera function and the slit lamp biomicroscope. Methods: Agreement of ToriExpertä against known reference source was tested under experimental situation. For clinical measurement, thirty three participants (66 eyes) wore toric lens (prism ballast design) both eyes. Two investigators measured toric lens rotation using the two methods which are slit-lamp measurement(HS-700) and mobile application. First investigator used the same method twice for assessment of test-retest repeatability of each method. Inter- and intra-investigator agreement and repeatability were assessed using Bland-Altman analysis. Results: Against the known reference sources, mean variance was 0.52±0.75 degree and limits of agreement was ±1.47 degree (95% of Cls). The limits of agreement between the silt-lamp biomicroscope and mobile application methods was ±9.1 degree (95% CIs). Measurements using the two different methods showed no statistically significant mean difference (paired t-test, p=0.32). Inter-investigator agreement of lens rotation was ±7.9 degree (95% CIs) using the slit-lamp microscope and ±7.8 degree using mobile application. Intra-investigator repeatability was ±6.6 degree using the slit lamp microscope and ±6.8 using mobile application. Conclusions: The results should be considered in view of the fact that soft toric lenses are not static but move with the blink thus the location of the reference point is unlikely to be at exactly the same location at the different measurement times. Despite this source of variability in the results, the newly developed mobile application provides clinically comparable performance to slit lamp biomicroscope measurement which does not appear to be investigator dependent. This mobile application may provide sufficient precision to those optometric practices have limited access to slit-lamp biomicroscope for measuring soft toric lens rotation.

16세기 후반에서 17세기 초에 우리나라에서 관측된 4개의 초신성(Tycho Supernova, Kepler Supernova, Cassiopeia Nova 및 Cassiopeia A)의 기록은 세계 어느 나라 천문관측기록 보다 더 자세히, 또 더 정확히 표시되어 있다. 특히 Kepler Supernova의 기록은 우리나라 이조 왕조실록에 가장 자세하게 실려있다. 위치뿐만 아니라 밝기, 관측시간 및 관측상태를 낱낱이 표기한 이 관측치로부터 다음과 같은 광도곡선상의 특징을 알아낼 수 있다. 1. 준극대광도(Pre-max-halt)는 1604년 10월 20일부터 10월 26일 사이 2. 극대광도(Maximum Luminosity)는 1604년 10월 29일부터 11월6일 사이 3. 천이과정(Transition)은 아마도 1604년 11월 28일부터 1604년 12월 26일 사이에 있었을 것이다.

Presumable explosion time of Cas A has been listed from Dec. 6, 1592 to Mar. 5, 1593 in ancinet Korean observational records. It may have been overlooked, due to other supernova(Cassiopeia Nova) which appeared at that time near its original position of Cas A.