Simone J N, Whitacre M M
Department of Ophthalmology, University of Kansas Medical Center, Kansas City 66103.
Ophthalmology. 1990 Feb;97(2):238-43. doi: 10.1016/s0161-6420(90)32599-x.
Large increases in the intraocular pressure (IOP) of postoperative gas-containing eyes may require the removal of gas or fluid to reduce the IOP to the normal range. Application of the ideal gas law to Friedenwald's equation provides a mathematical model of the relationship between IOP, intraocular gas and fluid volumes, and the coefficient of scleral rigidity. This mathematic model shows that removal of a given volume of gas or fluid produces an identical decrease in IOP and that the more gas an eye contains, the greater the volume reduction necessary to reduce the pressure. Application of the model shows that the effective coefficient of scleral rigidity is low (mean K, 0.0021) in eyes with elevated IOP that have undergone vitrectomy and retinal cryopexy and very low (mean K, 0.0013) in eyes with elevated IOP that have undergone placement of a scleral buckle and band. By using the appropriate mean coefficient of rigidity, the volume of material to be aspirated to produce a given decrease in IOP can be predicted with clinically useful accuracy.
术后含气眼的眼内压（IOP）大幅升高可能需要排出气体或液体，以使眼内压降至正常范围。将理想气体定律应用于弗里登瓦尔德方程，可得出眼内压、眼内气体和液体体积以及巩膜刚性系数之间关系的数学模型。该数学模型表明，排出一定体积的气体或液体可使眼内压产生相同程度的降低，且眼内所含气体越多，为降低眼压所需减少的体积就越大。该模型的应用表明，在接受玻璃体切除术和视网膜冷冻疗法的眼压升高的眼中，巩膜刚性的有效系数较低（平均K值为0.0021）；而在接受巩膜扣带术的眼压升高的眼中，该系数则非常低（平均K值为0.0013）。通过使用适当的平均刚性系数，能够以临床上有用的准确度预测为使眼压产生特定降低而需要吸出的物质体积。
