眼内計測による周辺虹彩前癒着の判別

Detection of peripheral anterior synechia by ocular biometry

　Shaffer分類Ⅱ度以下の狭隅角で明らかな周辺虹彩前癒着（PAS）のある50眼（狭隅角眼）の眼軸長，前房深度，水晶体厚，硝子体長を超音波Aモードで測定した。同様な生体計測を，Shaffer分類Ⅲ度とⅣ度の広隅角でPASのない67眼（広隅角眼）に対して行った。狭隅角眼では広隅角眼に比べ，眼軸長（p＜0.001），前房深度（P＜0.001），水晶体厚（p＜0.001）それぞれが有意に低値であった。硝子体長は両者間に有意差がなかった（p＜0.45）。眼内計測値の中で前房深度がPASの存在を最もよく判別し，そのカットオフ値は2.6mm （感厚：100％，特異度：82％）であった。

Ocular biometry was performed on 50 eyes with narrow angle of Shaffer grade Ⅱ or less with obvious peripheral anterior synechia (PAS). The findings were compared with another series of 67 eyes with wide angle of Shaffer grade Ⅲ or Ⅳ without PAS. An A-mode ultrasonography was used in the measurement. The narrow-angle eyes showed significantly smaller values than wide-angle eyes in axial length (p＜0.001), anterior chamber depth (p＜0.001), and lens thickness (p＜0.001). There was no significant difference between the two groups in the value of vitreous length (p＜0.46). The anterior chamber depth was the most useful indicator for PAS at the sensitivity of 100% and specificity of 82% with a cut-off of 2.6 mm.