Review Ioannis G Pallikaris †1

Institute of Optics and Vision, Department of Medicine, University of Crete, Greece Ophthalmology Department, University Hospital of Larissa, Greece Author for correspondence: [email protected] Ocular rigidity is a macroscopic parameter characterizing the relationship between pressure and volume changes in the human eye. Ocular rigidity depends on the architecture and material properties of the globe. Measurements of ocular rigidity have mainly been performed by means of invasive manometric devices or paired Schiotz tonometry. These measurements pertain to the injection (or displacement) of a given volume in the eye and measurement of the associated intraocular pressure change. Ocular volume, age, intraocular pressure, arterial pressure and ocular blood volume have all been suggested to influence ocular rigidity. Moreover, rigidity has been shown to be altered in patients with glaucoma and age-related macular degeneration. The significance of an accurate assessment of this parameter is apparent in tonometry, tonography and pulsatile ocular blood flow measurements, while its possible role in the pathogenesis of ocular disease remains to be elucidated.