波面センサーとオートケラトメータの角膜乱視の比較

Comparison of corneal astigmatism measured by autokeratometer and wavefront sensor

要約　目的：波面センサー（KR-9000PW，トプコン社）の，角膜形状解析後に高次収差を除外した乱視成分（WF乱視）と，オートケラトメータと同じ原理での測定による乱視（AK乱視）の比較。対象と方法：白内障術前103眼のWF・AK乱視の度数と軸角度を比較し，軸角度の相違と角膜高次収差の相関を検討した。結果：WF乱視度数はAK乱視より大きかった（p＝0.000072）。また両者の軸角度の相違は，乱視が小さいほど，また3次の収差が大きいほど，大きくなった。結論：両乱視で度数，軸は異なり，特に度数が小さい場合に軸の相違は顕著であった。トーリック眼内レンズの臨床において，より精緻な術前乱視の測定および手術適応の検討が重要であると考えられた。

Abstract.　Objective：To assess the agreement of magnitudes and axes of corneal astigmatism measured by corneal topographer and autokeratometer of hybrid wavefront sensor（KR-9000PW, Topcon）. Methods：The second corneal Zernike aberration（WF astigmatism）and autokeratometric（AK）astigmatism were measured and compared on preoperative 103 eyes. Correlations between the difference of these two astigmatism axis measurements and corneal higher-order aberrations（HOAs）were evaluated. Results：The magnitude of WF astigmatism is significantly greater than that of AK astigmatism（p＝0.000072）. The difference of axes of WF and AK astigmatism was greater, if the magnitude of astigmatism is small and if the third HOAs are greater. Conclusions：The magnitudes and axes differed in two astigmatism measurements, which is evident especially in axis measurement of eyes with low astigmatism. Thus it is desirable to thoroughly examine preoperative astigmatism and to consider the indication and usage of the toric intraocular lens.