Purpose
To assess ocular perfusion pressure (OPP) with automated measurements of blood pressure (BP) and intraocular pressure (IOP) in normal and normotensive glaucoma (NTG) patients, and to evaluate the corneal changes following 24-hour Triggerfish (Sensimed AG, Switzerland) contact lens sensor (CLS) wear.
Methods
Twelve normal and 3 NTG subjects completed keratometry, Snellen visual acuity, gonioscopy, Goldmann applanation tonometry (GAT), slit lamp examination (SLE) and fundoscopy in both eyes. Each subject wore an automated ambulatory BP monitor (ABPM) on the left arm and a CLS in the left eye for 24 hours. The CLS measures IOP related strain (mV Eq) at the corneoscleral junction. SLE and GAT were repeated after CLS removal to assess for corneal and conjunctival changes. Mean IOP and systemic BP during sleep and wake, and BP dip during sleep were calculated in 10 normal subjects. Three normal and 3 NTG subjects completed corneal topographic measurements (Galilei G4, Ziemer Ophthalmic Systems AG, Switzerland) before and after CLS wear. Pre- and post-CLS central anterior axial curvature (C-AAC), mean refractive power (MRP), total corneal power (TCP), and central and peripheral corneal thickness (CCT, PCT) were measured.
Results
Mean age was 52.3±13.4 years; 46.7% of participants were female. The mean, awake, and sleep systolic BPs (SBP, mmHg) were 138.5±12.0, 146.2±10.6, and 126.5±14.5, respectively. The mean, awake, and sleep diastolic pressures (DBP, mmHg) were 82.1±9.6, 85.7±10.6, and 72.1±9.4, respectively. The percentage dips between awake and sleep were 11.4% for SBP and 15.3% for DBP. The mean sleep and awake IOP equivalent (mV Eq) was 39.9 ± 183.9 and -45.7 ± 140.6, respectively. The pre- and post-CLS wear corneal topographic measurements were 43.4±1.7D and 43.8±2.7D for C-AAC, 43.7 ± 1.7D and 43.9±2.7D for MRP, 42.9±1.6D and 43.2D±2.8D for TCP, 547.7±30.3µm and 548.3±37.2µm for CCT, and 660.8±26.2µm and 669.1±22.3µm for PCT, respectively (all P>0.05). After CLS wear, 10 subjects had 360° conjunctival staining, 10 had central corneal epithelial staining, and 1 had Descemet’s folds.
Conclusions
During recumbent sleep systolic BP dips and IOP rises, decreasing nocturnal OPP. Despite clinical evidence of lens-associated staining of the cornea and conjunctiva there was no significant difference in corneal topography after 24-hour CLS wear.