Journal of Korean Ophthalmic Optics Society (한국안광학회지)

The Korean Ophthalmic Optics Society (한국안광학회)
권호 표지

The Study about Measuring Method in Radius of Eyeglasses Lens Curvature by using Keratometer

각막곡률계를 이용한 안경렌즈 곡률반경 측정방법에 관한 연구

  • Cha, Jung Won (Dept. of Ophthalmic Optics, Shinheung College University)
  • 차정원 (신흥대학교 안경광학과)
  • Received : 2012.05.07
  • Accepted : 2012.06.16
  • Published : 2012.06.30
Download PDF
⟨ Previous Next ⟩

Abstract

Perpose: The aim of this study is to investigate the measuring method in radius of eyeglasses lens curvature by using keratometer in noncontact method. Methods: A trial lens for vision test in diopter range from -9.00 D to -11.50 D were attached in front part of keratometer, after that we set eyeglasses lens at the place where eyeglasses lens is apart about 25 cm from front position of keratometer. We measured the radius of curvature from observation of clear mire image while the position of eyeglasses lens is changed in a small quantity. After that, we made some formulas for compensation of radius of curvature by using spherometer. Results: The radius of curvature was successfully measured by keratometer with trial lens in front part of it. The measured radius of curvature was changed to compensation value using spherometer data, and the 5 kind of linear equation to make compensation value was made. Any kind of lenses measured by using keratometer that trial lens was attached in front part of it, after that it was confirmed that the result of calculation from line equation is exact in error ratio below 3.5%. Conclusions: It was confirmed that radius of eyeglasses lens curvature can be measured by using keratometer by noncontact method, and the accuracy is higher than "lens measure".

목적: 각막곡률계를 이용하여 비접촉식으로 안경렌즈의 곡률반경을 측정할 수 있는 방법에 관하여 조사하고자 한다. 방법: 각막곡률계의 전면부에 -9.50 D ~ -11.50 D의 시력검사용 시험렌즈를 부착한 후 안경렌즈를 각막곡률계의 전면부에서 약 25 cm 가량 떨어진 곳에 설치한다. 안경렌즈의 위치를 조금씩 변경시키며 선명한 마이어상을 관찰하여 곡률반경을 측정한 후, 구면계를 이용하여 곡률반경의 보정공식을 만든다. 결과: 전면부에 시험렌즈를 부착한 각막곡률계를 이용하여 곡률반경 측정이 성공적으로 수행되었다. 측정한 곡률반경은 구면계 데이터를 이용하여 보정값으로 변환 되었으며, 보정값을 만드는 직선의 방정식 5가지를 얻었다. 임의의 여러 가지 렌즈들을 전면부에 시험렌즈가 부착된 각막곡률계로 측정한 후 직선의 방정식을 이용하여 계산한 결과 3.5% 미만의 오차로 측정이 가능함을 알았다. 결론: 전면부에 시험렌즈를 부착한 각막곡률계를 이용하여 비접촉식으로 안경렌즈의 곡률반경을 측정하는 것이 가능하며, 그 정확도는 렌즈메져보다 오히려 높은 것으로 나타났다.

Keywords

References

  1. Sung PJ. Optometry, 4th Ed. Seoul: Daihaks Publishing Co., 2004;64-69.
  2. Jung BY, Ju KB. Front Radius of Spherical Spectacle Lens in the Cosmetic and the Optical Considerations. J Korean Oph Opt Soc. 2005;10(4):405-410.
  3. Park SJ, Shin CG, Ju SH. The Influence of the Front Surface Power and the Refraction Index on RMS Spot Diameter. J Korean Oph Opt Soc. 2003;8(2):57-63.
  4. Kim SJ, Lim HS. The Performance Analysis and Design of Selling Spectacle Lenses in Domestic Market. J Korean Oph Opt Soc. 2010;15(4):355-360.
  5. Miks A, Novak J, Novak P. Third-Order Design of Aspheric Spectacle Lenses. Opt Int J Light and Electron Opt. 2010;121(23):2097-2104. https://doi.org/10.1016/j.ijleo.2009.07.008
  6. Weimin S, Mingqui X. Aberration Analysis and Optical Design of Aspheric Spectacle Lens. Acta Optica Sinica. 2002;22(6):743-748.
  7. Optometry Teaching Materials Compilation Committees. Optometric Instrumentation, 2nd Ed. Seoul: Daihaks Publishing Co., 2000;155-171.
  8. Optometry Teaching Materials Compilation Committees. Optometric Instrumentation, 2nd Ed. Seoul: Daihaks Publishing Co., 2000;47-49.
  9. Lee YW, Cho HM, Lee IW. Measurement of Long Radius of Curvature by Using Bidirectional Shearing Interferometer. J Opt Soc Korea. 1994;5(2):198-203.
  10. Shukla RP, Udupa DV, Sinha AK. Simple Method for Measuring Long Radius of Curvature of Metal Cylindrical Surface. Journal of Optics -Calcutta-. 2001;30(2): 73-83.
  11. Zhang H, Lalor MJ, Burton DR. Improved technique for measurement of a long radius of curvature by a digital moire method [3479-35]. Progress in Biomedical Optics and Imaging(SPIE Proceedings Series). 1998;3479:304-310.