To evaluate 24-hour continuous intraocular pressure (IOP) monitoring with a telemetric contact lens sensor (CLS) to detect prostaglandin-induced IOP reduction.
In this prospective interventional study 9 ocular hypertensive and primary open-angle glaucoma patients were washed out from IOP-lowering medication for 6 weeks. One study eye per patient underwent 3 baseline 24-hour measurement curves 4 days apart: 2 curves with Sensimed Triggerfish CLS and 1 curve with Goldmann applanation tonometry (GAT). Then the patients received travoprost monotherapy for 3 months. The 24-hour CLS and GAT curves were repeated on the study eyes under treatment at the end of the third month.
The 24-hour GAT IOP (mean±SD) decreased from 22.91±5.11 to 18.24±2.49 mm Hg (P<0.001). In contrast, the means of the 3 CLS curves showed no significant difference (152.94, 142.35, and 132.98 au, P=0.273). No difference was seen when the SD values of the 3 CLS curves were compared (133.51, 132.18, and 110.98 au, P=0.497). All CLS curves showed an increasing time trend (P≤0.001). Correlation of all 3 CLS curves of the individual eyes was high (r=0.726), but no correlation was seen between the corresponding CLS curve periods and GAT IOP values either at baseline (r=−0.223, P=0.546) or under treatment (r=0.320, P=0.402). No difference was seen between the erect/sitting (waking) and supine (sleeping) period CLS values (P>0.05).
Our results suggest that the current CLS technique cannot be clinically used to monitor IOP decrease induced by topical medication in glaucoma, and has limited value in identification of transient IOP elevation periods.