Metamorphopsia in neurological practice

Metamorphopsia is distortion of the visual perception of environmental objects (shape, sizes, orientation, color, and/or motion parameters), but without affecting their essential characteristics. It can be observed in the clinical picture of a number of diseases, interfering with daily activities and restricting the behavior of patients due to fear of its sudden occurrence. However, the importance of metamorphopsia is underestimated in practice, which is associated with both patients' tendency to be reticent about it and with physicians' unawareness about this condition. The review presents the classification of visual distortions, the clinical characteristics of peripheral (in eye structural pathology) and central (in brain damage) metamorphopsia. The most detailed discussion focuses on palinopsia. The Pulfrich phenomenon and the visual snow symptom are briefly described. The review considers metamorphopsia concurrent with illusions in the Alice-in-Wonderland syndrome. It characterizes the neurophysiological mechanisms of distorted vision and the pathology in which the latter can occur. There is evidence that it is important to timely detect metamorphopsia.