Abstract
Purpose:
IOP (intraocular pressure) is one of the most important risk factors for progression in glaucoma and reduction in IOP remains the main therapeutic tool to control glaucoma and reduce or even stop progression of associated visual field defects. Measuring IOP, not only at defined schedule visits, is an essential need for high qualified and significant glaucoma monitoring. The goal of this study is to evaluate the concordance of a minimal invasive implanted suprachoroidal pressure transducer with direct intracameral manometry.
Methods:
Suprachoroidal pressure transducers were implanted in 6 new zealand white rabbits. Microinvasive surgery was performed under general anesthesia. For implantation a scleral incision was performed to modulate a suprachoroidal pocket. The IOP sensor was then placed in this pocket. To verify the function of the implantable microsensor cannulation of the anterior chamber, with following simultaneous intracameral and telemetric IOP measurement, was performed at 1, 4, 8 and 12 weeks after implantation.
Results:
Bland-Altman plots were generated to evaluate the agreement between the telemetric and direct intracameral IOP measurements. The mean bias between the telemetric and the intracameral manometry was +0,35mmHg at 1 week, +1,72mmHg at 4 weeks, -0,19mmHg at 8 weeks and +3,57mmHg at 12 weeks after implantation. Limits of agreement (95% CI) showed a good concordance with upper limits of 9,4mmHg at 1 week, 13,5mmHg at 4 weeks, 5,6mmHg at 8 weeks and 8,1mmHg at 12 weeks after implantation and lower limits of -8,7mmHg at 1 week, -10,0mmHg at 4 weeks, -5,9mmHg at 8 weeks and -1,0mmHg at 12 weeks after implantation.
Conclusions:
Telemetric suprachoroidal implantable IOP microsensors showed reproducible IOP measurements with good concordance in IOP range between 10mmHg and 45mmHg. Continuous IOP monitoring will enable a new level of diagnostic methods allowing IOP self-measurements at any day or night time and help detecting elevated IOP levels or even IOP fluctuation und spikes. Furthermore telemetric IOP monitoring could even play an essential role in preventing glaucoma associated visual field defects.