糖尿病網膜症における脈絡膜血管障害

Choroidal vascular disorders in diabetic retinopathy

　糖尿病網膜症における脈絡膜血管障害の有無を検索した。単純糖尿病網膜症6眼，増殖網膜症29眼を対象とし，走査レーザー検眼鏡を使ってインドシアニングリーン（ICG）造影を施行した。一画角70°の広角画像を貼り合わせてパノラマ脈絡膜造影像を作製し，正常眼と比較した。フルオレセイン螢光造影を併せて行いICG画像と比較した。

　単純網膜症1眼と増殖網膜症21眼で黄斑部のびまん性螢光の減弱が観察された。網膜血管床閉塞が高度な6眼では中間周辺部で虫食い状の脈絡毛細管板の閉塞があった。増殖網膜症で脈絡毛細管板に変化のあった7眼では，脈絡膜の中・大静脈レベルで血管数の減少が観察され，うち6眼では渦静脈が狭細化していた。

　重症糖尿病網膜症では脈絡毛細管板や脈絡膜の中・大静脈に高率に血流障害があることが証明された。渦静脈は脈絡膜の血流障害時に狭細化することが推測された。

Purpose: To identify the presence of choroidal vascular disorders in diabetic retinopathy.Material and Method: A total of 35 eyes were studied. Simple diabetic retinopathy was present in 6 eyes and proliferative one in 29 eyes. In addition to conventional fluorescein angiography, each eye was studied by indocyanine green (ICG) angiography using a scanning laser ophthalmoscope, SLO. Panoramic composite angiograms were made by patching together the printed angiograms.

Findings: A decrease in background ICG fluorescence in the macular area was present in one eye with simple retinopathy and in 21 eyes of proliferative retinopathy. This finding seemed to show decreased perfusion in the choriocapillaris. Patchy areas of obliterated choriocapillaris in the midperipheral fundus were present in 6 eyes with extensive retinal capillary nonperfusion. The number of choroidal veins was decreased in 7 eyes of proliferative retinopathy with attenuated vortex veins in 6 eyes.

Conclusion: Impaired circulation in the choriocapillaris and choroidal veins were frequent features in proliferative diabetic retinopathy.