後房レンズ挿入術後の残余乱視

Residual astigmatism following posterior chamber lens implantation

　後房レンズ挿入術後の残余乱視の程度とその要因を明らかにするため，偽水晶体眼134眼と年齢でマッチングした対照眼134眼について，屈折と角膜曲率半径を計測した。術後群では残余乱視度は-0.8±0.6D （平均±標準偏差）で，対照群と比べて平均値に有意差はなかったが，6例（6％）に2.0Dを越える強い残余乱視を認めた。対照群では直乱視に集中する傾向があったのにたいし，術後群では残余乱視の乱視軸はランダムな度数分布を示した。嚢内固定でない例や眼内レンズの位置異常を示す例では，有意に大きい術後残余乱視を認めた。しかし，後房レンズを嚢内固定する限り，術後残余乱視は小さいと考えた。

We measured the state of refraction and corneal curvature in 134 pseudophakic eyes. All theeyes had undergone posterior chamber lens implantation. Another series of age-matched 134 phakic eyesserved as control. The calculated residual astigmatism averaged-0.8±0.6D in the pseudophakic group.There was no difference in residual astigmatism between the two groups. As a major difference, residualastigmatism greater than 2.0D was present in 6 eyes, 6%, in the pseudophakic group. The axis of astigma-tism was randomly distributed in the pseudophakic group, while direct astigmatism was the rule in thecontrols. Residual astigmatism was significantly greater in eyes with out-of-the bag fixation or withdecentrated lens. Residual astigmatism was therefore negligible in pseudophakic eyes when the lens wasproperly fixated.