The Korean Journal of Vision Science (대한시과학회지)

The Korean Society of Vision Science (대한시과학회)
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Change of Refraction while Viewing through the Periphery of Spectacle Lens

안경렌즈의 주변부 주시시 굴절변화

  • 문병연 (강원대학교 안경광학과) ;
  • 사종환 (강원대학교 안경광학과) ;
  • 유동식 (강원대학교 안경광학과) ;
  • 김상엽 (강원대학교 안경광학과) ;
  • 조현국 (강원대학교 안경광학과)
  • Received : 2018.05.10
  • Accepted : 2018.06.21
  • Published : 2018.06.30
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Abstract

Purpose : The purpose of this study was to investigate the change of refraction while viewing through the periphery of spectacle lens. Methods : In order to measure the change of refractive power while viewing through the periphery of the lens, the refractive power was measured with a digital lensmeter when the lens was tilted by gaze angle around a rotation axis which was 25 mm below from the lens support of lensmeter, and compared with refractive powers measured at the optical center and periphery. The effects of the refraction caused by the changes of lens thickness and vertex distance according to the gaze angle were also examined. Results : The thickness of a lens at a point of gaze was increased with the increase of the gaze angle, but not so much as to affect the correction power. As the gaze angle increased, the vertex distance increased and additional (-) correction power was required. At the gaze angles within $30^{\circ}$, the additional power was less than -0.1D. In most cases, as the gaze angle increased, the minimum refractive power (spherical power) was not significantly different from the reference refractive power. Cylindrical power was hardly observed up to about $10^{\circ}$, but increased with increasing the gaze angle. Conclusions : The change of refractive power caused by aberrations such as astigmatism in the peripheral vision should be considered in the use environment and handling of lenses.

목적: 안경렌즈의 주변부를 통해서 주시할 때 발생하는 굴절의 변화를 살펴보았다. 방법: 렌즈의 주변부를 통해 봤을 때 굴절력의 변화를 측정하기 위해 렌즈미터의 렌즈 받침부(lens support)로부터 25mm아래에 있는 회전축을 중심으로 주시각도만큼 렌즈가 기울어진 상태에서 렌즈미터로 굴절력을 측정하였으며, 광학중심부와 주변부에서 측정한 굴절력과 비교하였다. 또한 주시각도에 따른 두께의 변화와 정점간 거리의 변화가 굴절에 미치는 영향을 살펴보았다. 결과: 주시각도가 커짐에 따라 시선이 지나가는 렌즈의 두께는 증가하지만 교정굴절력에 큰 영향을 미칠정도는 아니었다. 주시각도가 증가하면 정점간 거리도 증가하게 되며 추가 (-)굴절력이 필요하다. 주시각도가 $30^{\circ}$이내일 때 추가 굴절력은 -0.1D이하이다. 주시각도가 증가할 때 최소굴절력(구면굴절력)은 기준굴절력과 대체로 큰 차이가 없었다. 원주굴절력은 주시각도 $10^{\circ}$정도까지는 거의 발생되지 않았으나 주시각도가 증가함에 따라 증가하는 경향을 보였다. 결론: 주변시에서 비점수차 등의 수차에 의한 굴절력의 변화는 렌즈의 사용 환경과 취급에서 고려되어야 할 것이다.

Keywords

Acknowledgement

Supported by : Kangwon National University

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