자동각막굴절계, IOL Master, 각막지형도의 각막굴절력 및 각막난시 측정의 비교 분석

목적: 백내장 수술 시 난시인공수정체 난시 도수를 정확히 결정하기 위해, 각막의 굴절력 및 난시 측정의 각 검사 간 재현성 및 난시 예측오차를 비교 분석하고자 하였다. 대상과 방법: 192명 254안의 의무기록을 후향적으로 분석하여, 자동각막굴절계, IOL Master, 각막지형도 검사를 통한 각막 굴절력의 재현성을 평가하였으며, 난시축의 일치 정도 및 난시값의 비교, 술 후 구면렌즈 대응치와 예측 인공수정체도수와의 차이로 예측오차를 비교 분석하였다. 결과: 평균 각막굴절력은 각막지형도에서 높았고, 난시는 IOL Master로 측정 시 높게 측정되었다. 평균 각막굴절력의 평균 coefficients of variation은 자동각막굴절계가 0.19%로 가장 낮았고, 난시축의 차이는 1.5D 이상에서는 통계적으로 유의미하지 않았다. 예측오차는 IOL Master와 자동각막굴절계의 측정값을 이용한 경우가 각막지형도의 측정값을 이용한 경우보다 작았다. 결론: 굴절력의 재현성은 자동굴절검사와 IOL Master 측정값이 높았고, 난시는 IOL Master로 측정 시 높았고, 1.5D 이상 난시의 축예측에는 각 검사가 일치하는 경향을 보였다. Purpose: To comparatively analyze the repeatability and consistency between different methods of measuring corneal refraction and astigmatism in order to precisely determine the toric intraocular lens target. Methods: The medical records of 254 eyes of 192 persons were retrospectively reviewed to compare the repeatability of corneal refraction measured with autokeratometer, IOL Master, and topography. The axis and the amount of the astigmatism were compared between these methods. The differences between the estimated spherical equivalents using measured corneal refractive values and the actual spherical equivalents after cataract surgery were compared to evaluate the expected astigmatic error of each measurement. Results: The average corneal refraction was greater with topography than with IOL Master or autokeratometer. Astigmatism calculated with IOL Master was greater than that measured with topography or autokeratometer. The mean coefficient of variation for mean corneal refraction was 0.19% with autokeratometer, which was smaller than that with IOL Master or topography. In patients with more than 1.5D of astigmatism, there were no significant differences in the axis measured by each instrument. The expected spherical error in IOL calculation was smaller with the measured values from IOL Master and autokeratometer than were those with topography. Conclusions: The repeatability of measurements for corneal refraction and astigmatism was significantly higher using the autokeratometer and IOL Master, with the highest astigmatic value observed with the IOL master. The axis of astigmatism for each method was consistent in the patients with more than 1.5D of astigmatism. J Korean Ophthalmol Soc 2011;52(12):1427-1433