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Loss of Corrected Visual Acuity According to Different Meridional Visual Acuity in Astigmatic Eyes

난시안에서 주경선 간 시력차이와 교정시력의 손실

  • 조나영 (강원대학교 안경광학과) ;
  • 김상엽 (강원대학교 안경광학과) ;
  • 문병연 (강원대학교 안경광학과) ;
  • 조현국 (강원대학교 안경광학과)
  • Received : 2016.02.03
  • Accepted : 2016.03.25
  • Published : 2016.03.31

Abstract

Purpose: This study was performed to investigate the difference of meridional visual acuity and the loss of corrected visual acuity (VA) in order to emphasis the importance of astigmatic correction. Methods: 64 subjects (122 eyes) aged $22.75{\pm}2.36years$ participated in this study. After full correction of astigmatic refractive error, VA was measured in which the direction of the slit filter was matched with astigmatic axis and $90^{\circ}$ to the astigmatic axis. Results: 52 eyes showed no difference in VA between the two direction. However 70 eyes had difference VA between them. 14 out of 52 eyes and 24 out of 70 eyes had under 1.0 in monocular VA. The astigmatic degree was higher in the existence of VA difference between the two direction than non-existence. The difference is higher with under 1.0 monocular VA. Monocular VA is closely related to the focal line having better VA in the principal focal line. Glasses replacement period was analyzed as 6~12 months for the preservation of better VA. Conclusions: The final glasses prescription has to be given with full correction because continued under-correction for astigmatism causes meridional VA difference.

목적: 난시교정의 중요성을 강조하기 위해 주경선 간 시력차이 유무와 교정시력의 손실정도를 알아보고자 하였다. 방법: 평균 나이 $22.75{\pm}2.36$세의 난시성 굴절이상자 64명(122안)을 대상으로 하였다. 난시안을 완전교정 한 후 열공판 중앙의 가는 틈을 난시교정 축방향과 $90^{\circ}$ 반대방향으로 일치시킨 상태에서 시력을 각각 측정하였다. 결과: 경선 간 시력차이가 존재하지 않는 경우는 52안이었고, 경선 간 시력차이가 존재하는 경우는 70안이었다. 단안시력이 1.0 미만인 경우는 52안 중 14안, 70안 중 24안으로 나타났다. 난시도는 경선 간 시력차이가 존재하는 경우가 경선간 시력차이가 존재하지 않는 경우보다 높게 나타났으며, 단안시력이 1.0 미만의 경우가 더 높은 것으로 나타났다. 단안시력은 주경선 중 시력이 높게 나타나는 경선과 높은 상관성을 보였다. 좋은 시력을 유지하기 적합한 안경 교체주기는 6~12개월로 분석되었다. 결론: 난시의 지속적인 저교정은 경선 간 시력차이를 일으키는 원인이 되므로 임상에서 난시안의 최종처방은 완전교정을 목표로 하여야 한다.

Keywords

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  1. Effect of Undercorrected Astigmatism on Visual Acuity According to Essential Astigmatism Power vol.23, pp.4, 2018, https://doi.org/10.14479/jkoos.2018.23.4.415