網膜動脈循環不全に併発した中心静脈閉塞症の1例

A case of acute central retinal vein occlusion associated with retinal arterial insufficiency

　82歳の男性で，網膜中心動脈不完全閉塞に中心静脈閉塞症を併発したと考えられ，同時に毛様網膜動脈の循環障害をも認めた症例を報告した．経過とともに，広範な毛細血管閉塞が進行したが，いわゆる出血型中心静脈閉塞症に比し，静脈のうっ血や網膜出血は比較的軽微であった．しかし，著明な循環の改善をみた毛様網膜動脈域では，出血の増加が顕著となった．

　本症例の発症過程は，中心動脈の循環不全による血流のうっ滞により，静脈血栓が形成され，この静脈圧の上昇によって毛様網膜動脈の循環障害を来たしたと考えられる．その後，毛様網膜動脈域では，循環改善による血管内圧の上昇が出血をもたらしたが，循環の改善が軽微であった中心動脈域では，出血が比較的少なかったものと推定される．

　したがって，出血型中心静脈閉塞症において，動脈循環不全による毛細血管障害が毛細血管閉塞に，循環回復時の血管内圧の上昇が網膜出血に関与している可能性があると考えた．

A 82-year-old male developed blurring of vision in his left eye. Funduscopv of the affected eye showed narrowing of retinal artery, macular edema and scat-tered retinal hemorrhages. Fluorescein angiography led to the diagnosis of central retinal vein occlusion and insufficiency of both central retinal and cilio-retinal arteries. Extensive capillary nonperfusion eventually developed, while the venous stasis and hemorrhages were less severe than in typical hem-orrhagic retinopathy. The insufficiency of ciliore-tinal artery became improved along with formation of an opticociliary vein. Retinal hemorrhage along the cilioretinal artery showed an increase.The course of events were interpreted by the following hypothesis. Central retinal artery occlu-sion would have induced stagnation and then occlu-sion of the central retinal vein. A decrease of pres-sure gradient between the cilioretinal artery and the occluded central retinal vein would lead to cilioretinal arterial insufficiency. The observed reti-nal hemorrhages after formation of optico-ciliary vein might be due to increased intraluminal pres-sure secondary to improved circulation in the cilio-retinal artery.