硝子体手術前後の視神経乳頭形状の変化

Volumetric changes in the optic disc following vitreous surgery

（C4-3-5）　硝子体手術を施行した／7眼（黄斑円孔9眼，網膜上膜5眼，糖尿病黄斑浮腫2眼，白内障術後の黄斑浮腫1眼）で術前，術後にHeidelberg Retina Tomographを用いて乳頭形状を記録重比較し，術中の硝子体操作時間，液ガス置換の有無や術中の灌流圧などとの関係を検討した。硝子体操作時間が長く，液ガス置換を行い，術中の灌流圧が高いほど，乳頭に長期間持続する変化を認めた。乳頭体積の変化の原因として，手術操作による神経線維の浮腫，乳頭部での毛細血管床の傷害による血漿成分の漏出などが考えられた。乳頭深度の増大の原因としては眼球壁の変形，神経線維に対する物理的傷害などが考えられた。硝子体手術時には可能な限り操作時間を短く作灌流圧を低く保つことが必要である。

We prospectively evaluated the volumetric changes in the optic disc in 17 eyes following vitreous surgery. The series comprised idiopathic macular hole 9 eyes, epiretinal membrane 5 eyes, diabetic macular edema 2 eyes and pseudophakic macular edema 1 eye. The optic disc was evaluated by a Heidelberg Retina Tomograph before and up to 6 months after surgery. The parameters of the optic disc included : cup/disc area ratio, cup volume, rim volume, and mean and maximum cup depths. Changes in these parameters were more pronounced along with longer duration of surgery, with fluid/air exchange and with higher intraoperative perfusion pressure. These changes appeared to have been induced by edema in retinal nerve fibers and extravasation of plasma components secondary to damaged capillaries in the optic nerve head. The findings show the necessity of shorter duration of surgery and lower perfusion pressure to avoid optic disc damage during vitreous surgery.