前眼部形状解析装置TMS-5による角膜径（white to white）測定の再現性と他機種との比較検討

Repeatablity of white-to-white measurements of corneal diameter by instruments including TMS-5

要約　目的：複数の装置で測定した角膜径の値の再現性と装置の比較の報告。対象と方法：屈折異常以外に疾患がない25例46眼を対象とした。男性13眼，女性33眼で，年齢は20～31歳（平均24歳）である。角膜の水平径の測定には，TMS-5，ORBSCAN Ⅱ^®，Pentacam^®を用いた。2検者がwhite-to-whiteを指標として3回ずつ計測した。結果：TMS-5よる角膜径は，自動測定で11.86±0.34mm，手動で11.87±0.34mmで，両者間に差がなく，検者間にも有意差がなかった。変動係数は，TMS-5による自動と手動測定値ともに2.9％，ORBSCAN Ⅱ^®が2.8％，Pentacam^®が3.9％であり，Bland-Altman Plots 95％信頼区間については，全機種で高い再現性を示した。TMS-5による測定値は，他機種よりも約0.4mm高値を示した。結論：TMS-5による角膜径の測定値の再現性は良好であり，他機種よりも高い値が得られた。

Abstract.　Purpose：To report repeatability and differences in corneal diameter measured by various instruments. Cases and Method：This study was made on 46 eyes of 25 cases who had no disorders other than refractive errors. The series comprised 13 male and 33 female eyes. The age ranged from 20 to 31 years, average 24 years. Horizontal corneal diameter was measured from white to white using TMS-5, ORBSCAN Ⅱ^®, and Pentacam^®. Measurement was repeated 3 times by two observers. Results：Corneal diameter averaged 11.86±0.34 mm and 11.87±0.34 mm when measured by automatic and manual mode of TMS-5 respectively. There was no difference between the two modes or between observers. Coefficient of variation was 2.9％ for both modes of TMS-5, 2.8％ for ORBSCAN Ⅱ^®, and 3.9％ for Pentacam^®. All instruments showed high repeatability. Corneal diameter measured by TMS-5 was larger than about 0.4 mm than other instruments. Conclusion：Corneal diameter measured by TMS-5 showed high repeatability. The value was greater by 0.4 mm than other instruments.