Journal of Korean Ophthalmic Optics Society (한국안광학회지)

The Korean Ophthalmic Optics Society (한국안광학회)
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A Relationship between Corneal Eccentricity and Stable Centration of RGP Lens on Cornea

각막 이심률과 RGP 렌즈의 중심안정위치와의 상관관계

  • Park, Eun Hye (Dept. of Optometry, Seoul National University of Science and Technology) ;
  • Kim, So Ra (Dept. of Optometry, Seoul National University of Science and Technology) ;
  • Park, Mijung (Dept. of Optometry, Seoul National University of Science and Technology)
  • 박은혜 (서울과학기술대학교 안경광학과) ;
  • 김소라 (서울과학기술대학교 안경광학과) ;
  • 박미정 (서울과학기술대학교 안경광학과)
  • Received : 2012.11.01
  • Accepted : 2012.12.15
  • Published : 2012.12.31
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Abstract

Purpose: The present study was performed to investigate a relationship between the stable centrations of spherical RGP lens and aspherical RGP lens on cornea and corneal eccentricity. Methods: Two RGP lenses with different designs were fitted in alignment, steep or flat on total 84 eyes having corneal eccentricity of 0.28~0.78. The stable centration of lenses on cornea was analyzed by taking photographs with a high-speed digital camera. Results: The stable centrations of spherical and aspherical RGP lenses in horizontal direction were decentrated to temporal side. More centration to median side was shown when corneal eccentricity was larger. The difference between the stable centrations of spherical and aspheric RGP lenses according to corneal eccentricity was bigger when the fitting state was flatter. The difference in the stable centrations of aspherical RGP lens was smaller than that of spherical RGP lens regardless of fitting status. The stable centrations of spherical and aspherical RGP lenses in vertical direction were located below corneal apex regardless of fitting status however, there was no significant difference analyzed by the variation of corneal eccentricity. However, there were many cases that RGP lenses were in upper eyelid with increasing corneal eccentricity. Conclusions: The consideration of corneal eccentricity is required for RGP lens fitting and manufacturing aspherical RGP lens since the stable centration of spherical RGP lens as well as aspherical RPG lens' centration was changed depending on corneal eccentricity.

목적: 본 연구에서는 각막 이심률과 RGP 렌즈의 중심안정위치와의 상관관계를 알아보고자 하였다. 방법: 각막 이심률이 0.28~0.78인 각막 84안을 대상으로 구면 및 비구면 RGP 렌즈를 피팅 상태를 달리하여 착용시키고 각막에서의 중심안정위치를 초고속 카메라로 촬영하여 분석하였다. 결과: 구면과 비구면 RGP 렌즈의 수평방향 중심안정위치는 이심률이 작은 각막에서는 귀쪽으로의 치우쳐짐이 컸으나 이심률이 큰 경우는 각막 중심에 더 가까이 위치하였다. 구면 및 비구면 RGP 렌즈 모두 피팅 상태가 플랫할수록 이심률에 따른 중심안정위치의 차이가 커졌으며, 비구면 RGP 렌즈의 경우 각막 이심률이 작은 경우와 큰 경우 모두 중심안정위치의 차이가 구면 RGP 렌즈 보다 더 적었다. 구면 및 비구면 RGP 렌즈 착용 시 수직방향으로의 중심안정위치는 피팅 상태에 상관없이 모두 각막 중심을 기준으로 아래쪽에 위치하였으며 각막 이심률에 따른 차이는 통계적으로 유의하지 않았다. 그러나 이심률이 클수록 RGP 렌즈가 상안검에 맞닿는 경우가 많았다. 결론: 각막 이심률에 따라 구면 RGP 렌즈뿐만 아니라 비구면 RGP 렌즈의 중심안정위치가 달라졌으므로 RGP 렌즈의 피팅 및 제조 시에 이러한 점들이 고려되어야 할 것으로 보인다.

Keywords

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