Comparison between the intraocular pressure fluctuations measured at home versus in the clinic / 国际眼科杂志(Guoji Yanke Zazhi)

AIM: To compare intraocular pressure (IOP) fluctuations measured at home and in the clinic over a 24-hour period.METHODS: A prospective investigational study.A total of 120 Chinese participants were selected from five communities in the Chengdu area.Patients underwent a clinical interview and IOP was measured both at home and in the clinic.IOP were measured at 8 a.m., 10 a.m., 12 a.m., 2 p.m., 4 p.m., 6 p.m., 8 p.m., 10 p.m., 2 a.m., 6 a.m.using the same pneumatonometer.Measurements were taken in the sitting position.RESULTS: The average 24-hour IOP measured in the clinic was slightly lower than that at home.The mean difference in 24-hour IOP measurements between home and clinic was 0.27 mmHg.The IOP fluctuation in the clinic was higher than at home (the mean difference was 0.01 mmHg).There was no statistically significant difference in the average 24-hour IOP measured at home vs in the clinic.The average IOP measured at 2 p.m.at home (16.04±5.95 mmHg) was significantly higher compared with the measurement in the clinic (15.43±5.16 mmHg) (P<0.05).The overall agreement between 24-hour IOP measurements made in the clinic and at home in diagnosis of primary open angle glaucoma was 85.0% (K coefficient: 0.68).CONCLUSION: The 24-hour IOP measured in the clinic was similar to that measured at home, and the method of measuring IOP in the clinic is acceptable in diagnosing primary open angle glaucoma.

Advances in intraocular pressure measurement after corneal refractive surgery / 中华实验眼科杂志

After corneal refractive surgery,patients need to use glucocorticoids for a long time to control the wound healing,However,it can cause elevated intraocular pressure,even glucocorticoid-induced glaucoma,therefore properly evaluating patients' postoperative intraocular pressure (IOP) to avoid missing diagnosis of glucocorticoidinduced glaucoma and timely find glaucoma patients after corneal refractive surgery has an important clinical significance.The central corneal thickness (CCT),corneal curvature (CC),ablation depth,preoperative IOP and corneal biomechanics are responsible for IOP changes after corneal refractive surgery.To obtain accurate IOP value after corneal refractive surgery,this article reviewed the IOP measurements and their influential factors after surface,lamellar and all-in-one femtosecond laser refractive surgery.

Design of an Electromagnetic Pressure Control System in Intraocular Pressure Measurement / 中国医学物理学杂志

Objective:This paper studied the electromagnetic-driven pressure control system in the automatic measurement of intraocular pressure (IOP).The accuracy of pressure control directly impacts on the accuracy of IOP measurements,so it calls for precise pressure to achieve closed-loop control.Methods:According to the actual needs of IOP measuring,we got the structural and electromagnetic parameters of the electromagnetic drive system by combining the methods of numerical calculation and ANSYS simulation.Using the FC bus and digital-analog conversion,the microcontroller module controlled the drive current digitally and precisely in order to achieve closed-loop control of pressure.Results:The experimental results showed that in the electromagnetic pressure control system,the pressure range was 0 N～0.48982 N,the accuracy 0.00058 N,the drive current control error about 1% on average.Besides,the electromagnetic force and the excitation current showed a good linear relationship in the same stroke.Conclusions:The electromagnetic pressure control system achieved a good result in closed-loop control of pressure.The control pressure range and control accuracy were in line with the standard of Goldmann applanation tonometer.According to the results,this study laid the foundation for the further development of IOP automatically measuring instruments.