モードロック方式YAGレーザーによる後部硝子体手術

Use of mode-locked YAG laser in the treatment of vitreous strands and membranes

　モードロック方式によるNd・YAGレーザーを用い，硝子体腔内に網膜を牽引する病変を示す16症例（糖尿病性網膜症6例，網膜静脈分枝閉塞症3例，その他5例）の治療を行い，これに成功した．後部硝子体における増殖組織のYAGレーザーによる切断は，緊張を持った膜性の病変でより容易に実施できた．緊張が少なく，明瞭な索形成の見られない硝子体混濁の場合には若干の困難を伴った．

　一度の照射回数は，平均560回（最低71，最高1272）であり，症例により，一度ないし数度で満足できる硝子体切断が完成した．

　術中の合併症は2例にみられ，硝子体新生血管からのわずかな出血と，網膜の白い凝固斑であったが，いずれも一過性であって，術後の経過に悪影響を残さなかった．

Mode-locked YAG laser was used in severing vitreous strands or membranes in 16 eyes. The casesincluded proliferative retinopathy (6 eyes), branch retinal vein occlusion ( 3 ), acute retinal necrosis ( 1 ) and others. While attempting to sever vitreal mebranes, a number of consecutive shots were appli-ed to create a tiny hole. This procedure was repeat-ed until a row of holes were formed transversing the membrane at a right angle to the force of stretch. These holes were then made to merge so as to cut the whole membrane at the desired site.As a standard setting, we used the power output of 4 m J for each burst. A total of 71 to 1,272 bursts, average 560, were necessary to sever a membrane or a strand in the present series. The sites of vitreous strands or membranes to be treated were located, in the majority of cases, either in the middle or posterior vitreous. The distance between the site of laser application and the retinawas :imm or more. As a major complication, he-morrhages occurred from the severed portion of fibrovascular membrane in 1 eye. This hemorrhage was temporary and disappeared without sequelae when examined 24 hours later. Retinal burn, simi-lar in appearance as in conventional argon laser treatment, developed in 1 eye. No further com-plications were observed throughout the series.