부산대학교 도서관

Purpose The intraocular pressure (IOP) is determined by a dynamic equilibrium between the production and the outflow of the aqueous humor. The dependence of outflow facility on IOP may be related to the biomechanical properties of the eye. This study examines the relationship between the outflow facility and IOP for the living human eye using an invasive manometric device. Methods An intraoperative invasive manometric device was used to measure the IOP of fifty four eyes from fifty four cataract patients. The measurements were performed before cataract surgery. The anterior chamber of the eye was cannulated to a microstepping pump and the pressure was recorded by a pressure transducer through special developed computer software. The IOP was artificially increased to 40 mmHg by infusion of BSS in the anterior chamber of the eye. The IOP decay curve was recorded. A mathematical model was developed to calculate the outflow facility coefficient. Results The average outflow facility coefficient was 0.328 (SD 0.093) μl/min/mmHg. From the data analysis the outflow facility coefficient was proved to have a non linear correlation with IOP. This non linear behavior of outflow facility was approximated with an exponential mathematical model. Conclusion The invasive method of measuring in vivo outflow facility coefficient employed in this study, avoiding the errors of tonography may provide accurate data on the dependence of outflow facility coefficient on IOP. These data, in conjunction with ocular rigidity measurements may facilitate our understanding of the relationship between the biomechanical properties of the eye and the anatomical changes in the trabecular area at elevated IOP levels. [ABSTRACT FROM AUTHOR]