Intraocular Pressure Measured by a Novel Sensing Contact Lens Versus Tonometry

While elevated intraocular pressure (IOP) is no longer part of the definition of glaucoma it remains the sole proven modifiable risk factor for the onset and progression of glaucoma. IOP is known to vary with the time of day as well as with daily activities. The importance of the nycthemeral IOP pattern for successful management of glaucoma has been well documented, especially for patients who experience visual loss despite apparently normal and/or controlled IOP during office hours. The current way of assessing nycthemeral IOP fluctuation is to perform repeated discrete tonometry measurements, once per hour in the best cases. Since its development in the 50s, Goldmann applanation tonometry (GAT) has remained the gold standard method for measuring IOP, despite its limitations. However, tonometry may be an imperfect method for measuring changes in IOP because it allows only snapshot and non-continuous measurements, it is not physiologic and disturbs the sleep architecture. There have been many efforts in the past decades to search for an ambulatory and frequent method to monitor IOP for 24 hours. In this context, Sensimed AG has recently developed a sensing contact lens-based device intended to measure IOP over 24 hours, the Goldfish (GF). First-in-man data obtained with this device showed agreements between IOP measured by GF and values obtained by standard tonometry in the same eye, comparable to literature results for routinely used tonometry devices. However, this pilot study included 9 subjects only with improvable safety, tolerability and efficacy profiles. The main goal of this study is to assess IOP measurements with the GF and compare the values with those obtained by standard tonometry in patients with open angle glaucoma (OAG) and ocular hypertension (OHT).