RT Journal Article SR Electronic T1 Twenty-four hour intraocular pressure monitoring with the SENSIMED Triggerfish contact lens: effect of body posture during sleep JF British Journal of Ophthalmology JO Br J Ophthalmol FD BMJ Publishing Group Ltd. SP 1323 OP 1328 DO 10.1136/bjophthalmol-2016-308710 VO 101 IS 10 A1 Beltran-Agulló, Laura A1 Buys, Yvonne M A1 Jahan, Farzana A1 Shapiro, Colin M A1 Flanagan, John G A1 Cheng, Jason A1 Trope, Graham E YR 2017 UL http://bjo.bmj.com/content/101/10/1323.abstract AB Purpose To determine the difference in relative intraocular pressure (IOP) measured by the SENSIMED Triggerfish (TF) contact lens in flat compared with 30° head-up sleeping positions in patients with progressive primary open-angle glaucoma or normotensive glaucoma, based on recent or recurrent disc haemorrhage.Design Prospective, randomised, cross-over, open-label comparative study.Methods IOP was monitored for 24 hours using TF on two separate sessions. Patients were randomly assigned to sleep flat one night and 30° head-up the other. Outputs in arbitrary units were obtained. Sleep and wake periods were defined as 22:00–6:00 and 8:00–22:00, respectively. Mean TF values during sleep and wake periods and wake–sleep and sleep–wake slopes were calculated for each session. TF output signals were compared between positions.Results Twelve subjects completed the study. Significant mean positive slopes were noted during the sleep period for both positions (p<0.01). No significant differences in the TF mean values were observed between positions (p=0.51). Six (54%) subjects had mean TF values significantly higher during the flat supine session, while four (36%) subjects had higher values during the head-up session. A significant increase in Goldmann IOP (p=0.001) and TF (p=0.02) measurements were observed after 24 hours of TF wear (‘drift phenomenon’).Conclusions Sleep position affects IOP as measured by TF in some patients with progressive glaucoma. The upward drift in TF output detected in >50% of the subjects requires further investigation to establish whether the increased output values over time are an artefact induced by the TF or a real change in IOP.Trial registration number NCT01351779