白内障手術における線状刀刺出点の検討（第2報）

The apparent direction of Graefe's knife in anterior chamber. II. Influence of several factors

　線状刀を用いて角膜切開を行う場合の刺出目標について，第1報^1）において前房内線状刀のsa—gittal結像による見かけ位置を基に検討したが，今回は非点収差によるmeridional,sagittal及び最小錯乳円の像位置を計算し，さらに観察角，角膜曲率半径，角膜切開の長さが，真の刺出点と刺出目標点との間の喰違いに及ぼす影響について綜合的な検討を行なつた。

The apparent displacement of the Graefe's knife in the anterior chamber was calculated with the ray-tracing method, in an attempt to verify the time-honoured maxim that the knife has to be directed 1 mm centrally from the limbus in order to let it emerge at the corneoscleral margin.

While the corneal curvature scarcely influ-enced the apparent depth of the knife, thedistance between the aimed and the real emerging point increased the more as the peripheral cornea became the more flattened, a phenomenon explained from the geome-trical rather than optical reason.