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Purpose: Acute zonal occult outer retinopathy (AZOOR) is one of the "white dot syndromes" a clinically heterogeneous group of inflammatory chorioretinopathies. The etiology is not yet clear. Methods: We present a 50 years female patient with a prior history of migraine. She experienced progressive visual loss and visual field defects in the last 3 years. Preceding each episode she experienced blue flickering photopsias. Results: Visual acuity was 0,3 in the right eye and 0,6 in the left eye. Biomicroscopy showed a normal anterior segment, fundus exam revealed pigment epithelial atrophy more pronounced in the worse eye. Electrophysiology showed a marked reduction in the photopic ERG in the more affected eye. MRI demonstrated multiple white matter lesions including a corpus callosum location. Lumbar puncture showed oligoclonal bands. Further tests demonstrated hearing impairment. Therapy was instituted during the three years course of the disease with steroids, immune suppressants and plasmapheresis with visual loss being progressive. New photopsia is currently present. Conclusions: The etiology of AZOOR remains unclear. With our patient being one of the few described in the literature with concomitant multiple sclerosis, the question remains on whether there is an underlying common process of inflammatory autoimmune reactions. Whether treatment is possible, remains to be evaluated.

The term ocular rigidity is widely used in ophthalmology. Generally it is assumed as a measurable physical parameter related to biomechanical properties of the whole eye globe. Formulas for clinical tonometry and tonography methods include the concept of ocular rigidity. Unfortunately ocular rigidity represents an elusive concept that means many things to many people. First of all, there is no consensual view on ocular rigidity in ophthalmology. The most of the formulas for ocular rigidity are based on discrete or continuous tonometric measurements in living or enucleated human eyes. Surprisingly ocular rigidity is measured in different units and has a different meaning by different authors. Finally, there is no clear consent between biomechanical engineers and ophthalmologists on the concept of ocular rigidity. In biomechanics parameters for the elasticity and viscoelasticity are accepted, which represent mechanical properties of a tissue an can consider its morphology. These are for example: Young’s moduli of the sclera, Poisson’s ratios of the cornea etc. Ophthalmological concepts on ocular rigidity are based on the consideration, that biomechanical properties of the corneoscleral shell are involved in the pressure‐volume relationship of the eye globe. Ocular rigidity defined in such a way climes to describe the total response of the eye without detailed considerations on its morphologic and material properties. In the proposed review several formulations of ocular rigidity are analysed and classified. It is attempted to link these conceptions with each other.

Ocular rigidity in ophthalmology is generally assumed to be a measurable surrogate parameter related to the biomechanical properties of the whole globe. Clinical tonometry and tonography, as well as recently developed methods to assess the ocular pulse amplitude and pulsatile ocular blood flow and measurements with the ocular response analyzer are based on the concept of ocular rigidity. Clinical concepts of ocular rigidity describe a resulting effect without considerations of possible diverse morphology and material properties of the different ocular tissues. It is commonly accepted that ocular rigidity is related to the elasticity of the sclera. Many formulations are however dependent on the internal volume of the globe, intraocular pressure, corneal biomechanics and thickness of the corneoscleral shell. Sometimes this is extended to biomechanical properties of the ocular vasculature and perfusion pressure. Therefore ocular rigidity is expressed in various units and has different physical meanings but the same name is used which is confusing. Ocular biomechanics introduces parameters of elasticity and viscoelasticity of the sclera, cornea and other tissues which consider the morphology of the different tissues describing their mechanical properties such as: Young’s modules of the sclera and Poisson’s ratios of the cornea. When applying these rigorous statements and methods of biomechanical modeling a unified concept for ocular rigidity can be developed in order to link the limited clinical concepts, to improve them and to better understand the results of clinical measurements.