ヘルペス性角膜実質炎後の角膜の電子顕微鏡的観察

Ultrastruture of the cornea after herpetic stromal keratitis

　樹枝状角膜炎から円板状角膜実質炎になった2眼に全層角膜移植を行い，得られた角膜を透過型電子顕微鏡で検索した。17年前に発症し，2年後に再発が1回あった61歳女性では，角膜上皮細胞の層が少なく，表層の2～3層以外は暗細胞で，基底細胞も暗細胞であった。Bowman膜はほぼ正常で，変形が強い実質細胞を含み，核に変形像があった。内皮細胞は明細胞で，ミトコンドリアの変形萎縮があった。高電子密度の顆粒が多数あった。電子密度が高い限界膜に囲まれた空胞の中に無構造物質があった。20年前に発症し，複数回の再発があった51歳男性では，Bowman膜が障害され，特異な結晶構造の好酸球が実質に浸潤し，膠原線維束の走行が乱れていた。Bowman膜と角膜実質の障害が高度にあったのは，ヘルペス性角膜実質炎の頻回再発の結果であると推定した。摘出した角膜を検索することは，術後の治療方針の参考にもなる。

We performed penetrating keratoplasty on two eyes of disciform keratopathy secondary to dendritic keratitis. Both corneal buttons were examined by electron microscopy. One specimen was from a 61-year-old female. She had had dendritic keratitis 17 years before with one recurrence of disciform keratitis. The epithelial layer was thin. The keratocytes showed degenerated nuclei. Stromal lamellae retained their normal structure. Endothelial cells appeared as clear ones and contained atrophic metochondria with numerous granules of high electric density. There were empty vesicles with high electric density limiting membrane. Another 51-year-old male had multiple recurrences of disciform keratitis. His cornea showed destroyed Bowman's membrane. The stroma was infiltrated by numerous inflammatory cells containing eosinocytes. Stromal fibers were irregularly arranged. Recurrences of herpetic stromal keratitis appeared to have damaged the Bowman's membrane and the stroma. Examination of removed corneal buttom may serve as guidelines for postoperative treatment.