<unk>  can be separated into two categories, "inconspicuous<unk> " or "gross<unk> ", based on symptom severity and the amount the<unk>  affects the patient's quality of life. Inconspicuous<unk>  Inconspicuous<unk>  is often described by seeing motion as a cinema reel or a multiple exposure photograph. This is the most common kind of<unk>  and many patients consider the stroboscopic vision as a nuisance. The<unk>  often occurs with visual trailing (palinopsia), with afterimages being left at each frame of the motion. It is caused by prescription drugs, hallucinogen persisting perception disorder (HPPD), and persistent aura without infarction. The pathophysiology of<unk>  palinopsia is not known, but it has been hypothesized to be due to inappropriate activation of physiological motion suppression mechanisms which are normally used to maintain visual stability during eye movements (e.g. saccadic suppression). Gross<unk>  Gross<unk>  is an extremely rare condition. Patients have profound motion blindness and struggle in performing the activities of daily living. Instead of seeing vision as a cinema reel, these patients have trouble perceiving gross motion. Most of what is known about this extremely rare condition was learned through the case study of one patient, LM. LM described pouring a cup of tea or coffee difficult "because the fluid appeared to be frozen, like a glacier". She did not know when to stop pouring, because she could not perceive the movement of the fluid rising. LM and other patients have also complained of having trouble following conversations, because lip movements and changing facial expressions were missed. LM stated she felt insecure when more than two people were walking around in a room: "people were suddenly here or there but I have not seen them moving". Movement is inferred by comparing the change in position of an object or person. LM and others have described crossing the street and driving cars to also be of great difficulty. LM started to train her hearing to estimate distance. A change in brain structure (typically lesions) disturbs the psychological process of understanding sensory information, in this case visual information. Disturbance of only visual motion is possible due to the anatomical separation of visual motion processing from other functions. Like<unk> , perception of color can also be selectively disturbed as in achromatopsia. There is an inability to see motion despite normal spatial acuity, flicker detection, stereo and color vision. Other intact functions include visual space perception and visual identification of shapes, objects, and faces. Besides simple perception,<unk>  also disturbs visuomotor tasks, such as reaching for objects and catching objects. When doing tasks, feedback of one's own motion appears to be important.
Akinetopsia
Palinopsia
Photopsia
Pelopsia
Dysmorphopsia
Oscillopsia
Agraphesthesia
Cyanopsia