Cutting Edge Glaucoma - Issue 2

50 • CUTTING EDGE - GLAUCOMA before a button is pressed on the reader to activate the electromagnetic coupling sequence—this is all the cooperation required from the patient. The sensor can conduct up to 10 measurements per second. The ophthalmologist receives the patient’s IOP measurements by telemetry and can easily create the patient’s tension profile, detect dips and peaks during diurnal and nocturnal IOP fluctuations, and recognize situations that require an adjustment to the therapy [23]. In an animal model, reliable IOP readings were possible without any human interaction. The device recorded the diurnal and nocturnal IOP-lowering effects of two antiglaucomatous drugs, latanoprost and dorzolamide [33]. The first clinical experiences with the sensor are encouraging. Though reports have thus far been anecdotal, implantation of the sensor went smoothly in our clinic, and the measurements, readings, and transmission of data were found to be reliable and uncomplicated [6]. The long-term safety of the intraocular sensor was confirmed in a small group of patients ( n = 5) with an average follow-up of 37.5 months [17]. The intraocular sensor gives the eyecare provider a tool for noninvasively assessing the IOP at different times of the day (and night) and during different activities in the patient’s daily life. Without any doubt, the analysis of these measurements and their impact on clinical practice requires more studies with larger groups of patients. It will be interesting to see how the IOP values documented by the sensor relate to Goldmann applanation tonometry, which is generally considered to be the gold standard method of measuring the IOP more than 60 years after its invention [16]. The concept of measuring the IOP intraocularly and continuously holds promise [24] and will certainly lead to further developments and new technologies, some of which appear to be on the horizon. For instance, a wireless implantable intraocular pressure monitor microsystem (IMM) that comprises a powering coil, an antenna, and a piezoresistive microelectromechanical system pressure sensor was recently described by Bhamra et al . That sensor, integrated on a 5-μm-thick biocompatible Parylene C substrate, was reported by the authors to have been implanted into laboratory rodents [3]. Also, an optomechanical implant using an artificial neural network (ANN) has been implanted into rabbits, as reported by Kim et al . [15]. Medical Therapy Initiated by Surgical Procedure: Intraocular Drug Delivery Visual field loss in glaucoma represents irreversible damage to visual function. It is crucial to diag- nose and treat glaucoma in order to stop or at least slow the progression of the disease and thus delay additional optic nerve damage. The Achilles heel of conservative glaucoma therapy is the often less-than-stellar adherence. Many patients do not apply their antiglaucomatous eye drops correctly, as frequently as ordered, or at all. In a survey of 190 glaucoma patients in the United States who were taking one or more medications, 27% reported poor compliance. The most important risk factors for nonadherence in that study were decreased self efficacy (odds ratio, OR: 4.7) and problems with administering the IOP-lowering eyedrops (OR 2.3). Other causes of insufficient adherence were forgetfulness (OR 5.6) and difficulties with the medication schedule (OR 2.9) [29]. There is a social imbalance in adherence: glaucoma patients who are more afflu- ent, older, and white (compared to minority groups in the U.S. population) tend to show better