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Intermittent Photic Stimulation
In medicine, Intermittent Photic Stimulation, or IPS, is a form of visual stimulation used in conjunction with electroencephalography to investigate anomalous brain activity triggered by specific visual stimuli, such as flashing lights or patterns. IPS and EEGs are often used to diagnose conditions such as photosensitive epilepsy. The field is relatively new and the details of use of IPS have not been widely standardized. IPS is often used in conjunction with other controllable generators of visual stimuli, such as low-level visual stimulation LLVS. Photic stimulation may also be used to elicit myoclonus, especially cortical reflex myoclonus when present in photo-sensitive forms. IPS may be used to stimulate the visual system for patients with amblyopia. This system uses a visual stimulus that is usually red in color with a frequency of about 4 Hz to stimulate the neural pathway between the retina and the visual cortex. The objective is to improve the visual acuity ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Photosensitive Epilepsy
Photosensitive epilepsy (PSE) is a form of epilepsy in which seizures are triggered by visual stimuli that form patterns in time or space, such as flashing lights; bold, regular patterns; or regular moving patterns. PSE affects approximately one in 4,000 people (5% of those with epilepsy). Signs and symptoms People with PSE experience epileptiform seizures upon exposure to certain visual stimuli. The exact nature of the stimulus or stimuli that triggers the seizures varies from one patient to another, as does the nature and severity of the resulting seizures (ranging from brief absence seizures to full tonic–clonic seizures). Many PSE patients experience an " aura" or feel odd sensations before the seizure occurs, and this can serve as a warning to a patient to move away from the trigger stimulus. The visual trigger for a seizure is generally cyclic, forming a regular pattern in time or space. Flashing lights or rapidly changing or alternating images (as in clubs, around ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Low-level Visual Stimulation
High-level and low-level, as technical terms, are used to classify, describe and point to specific goals of a systematic operation; and are applied in a wide range of contexts, such as, for instance, in domains as widely varied as computer science and business administration. High-level describe those operations that are more abstract in nature; wherein the overall goals and systemic features are typically more concerned with the wider, macro system as a whole. Low-level describes more specific individual components of a systematic operation, focusing on the details of rudimentary micro functions rather than macro, complex processes. Low-level classification is typically more concerned with individual components within the system and how they operate. Features which emerge only at a high level of description are known as epiphenomena. Differences Due to the nature of complex systems, the high-level description will often be completely different from the low-level one; and, th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amblyopia
Amblyopia, also called lazy eye, is a disorder of sight in which the brain fails to fully process input from one eye and over time favors the other eye. It results in decreased vision in an eye that typically appears normal in other aspects. Amblyopia is the most common cause of decreased vision in a single eye among children and younger adults. The cause of amblyopia can be any condition that interferes with focusing during early childhood. This can occur from poor alignment of the eyes (strabismic), an eye being irregularly shaped such that focusing is difficult, one eye being more nearsighted or farsighted than the other (refractive), or clouding of the lens of an eye (deprivational). After the underlying cause is addressed, vision is not restored right away, as the mechanism also involves the brain. Amblyopia can be difficult to detect, so vision testing is recommended for all children around the ages of four to five. Early detection improves treatment success. Glasse ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Visual Acuity
Visual acuity (VA) commonly refers to the clarity of vision, but technically rates an examinee's ability to recognize small details with precision. Visual acuity is dependent on optical and neural factors, i.e. (1) the sharpness of the retinal image within the eye, (2) the health and functioning of the retina, and (3) the sensitivity of the interpretative faculty of the brain. The most commonly referred visual acuity is the far acuity (e.g. 6/6 or 20/20 acuity), which describes the examinee's ability to recognize small details at a far distance, and is relevant to people with myopia; however, for people with hyperopia, the near acuity is used instead to describe the examinee's ability to recognize small details at a near distance. A common cause of low visual acuity is refractive error (ametropia), errors in how the light is refracted in the eyeball, and errors in how the retinal image is interpreted by the brain. The latter is the primary cause for low vision in people with a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
