正常人眼内压的昼夜变化可达9mmHg,高于10mmHg者罕见。增加眼内压的生理因素有:房水流入增加、房水流出阻力增加以及静脉,特别是上巩膜静脉压升高。影响眼内压的其他生理变化包括:瞳孔扩大妨碍房水流出。体位变化,由直立位到坐位眼内压升高;仰卧位眼内压会进一步升高;如呈垂头仰卧位(Trendelenburg氏体位)则眼内压升得更 Normal intraocular pressure diurnal changes up to 9mmHg, higher than 10mmHg are rare. Physiological factors to increase intraocular pressure are: increased aqueous inflow, aqueous humor outflow resistance increases, and the veins, especially the scleral venous pressure. Other physiological changes that affect intraocular pressure include: Enlarged pupils impede the flow of aqueous humor. Changes in body position, from the upright to the seat intraocular pressure increased; supine position intraocular pressure will be further increased; such as vertical head supine position (Trendelenburg’s position) intraocular pressure rise more