Plaque-forming unit: In virology, a plaque-forming unit (PFU) is a measure of the number of particles capable of forming plaques per unit volume, such as virus particles. It is a functional measurement rather than a measurement of the absolute quantity of particles: viral particles that are defective or which fail to infect their target cell will not produce a plaque and thus will not be counted.Meridian (perimetry, visual field): Meridian (plural: "meridians") is used in perimetry and in specifying visual fields. According to IPS Perimetry Standards 1978 (2002): "Perimetry is the measurement of [an observer's] visual functions ...ScotomaOperation Eyesight Universal: Operation Eyesight Universal is a Canada-based international development organisation, founded in 1963. It works to prevent avoidable blindness and to cure blindness that is treatable.Landolt CMark III (radio telescope): The Mark III was a portable and fully steerable radio telescope located at Wardle, near Nantwich, Cheshire in the north-west of England (at ). Constructed in 1966, it was remotely controlled from Jodrell Bank Observatory, and was mainly used as part of the MERLIN radio telescope network.Charles D. Phelps: Charles Dexter Phelps (September 16, 1937 – September 13, 1985) was a prominent American medical doctor, professor, and researcher in the field of ophthalmology. The clinical studies he oversaw contributed to significant advances in the scientific understanding and surgical and pharmacological treatment of glaucoma.Homonymous hemianopsiaLogMAR chart: A LogMAR chart comprises rows of letters and is used by ophthalmologists and vision scientists to estimate visual acuity. This chart was developed at the National Vision Research Institute of Australia in 1976, and is designed to enable a more accurate estimate of acuity as compared to other charts (e.LevobetaxololIntraocular pressurePercolation threshold: Percolation threshold is a mathematical concept related to percolation theory, which is the formation of long-range connectivity in random systems. Below the threshold a giant connected component does not exist; while above it, there exists a giant component of the order of system size.Generalizability theory: Generalizability theory, or G Theory, is a statistical framework for conceptualizing, investigating, and designing reliable observations. It is used to determine the reliability (i.Curiosity: Curiosity (from Latin curiosus "careful, diligent, curious," akin to cura "care") is a quality related to inquisitive thinking such as exploration, investigation, and learning, evident by observation in human and animal species. Curiosity is heavily associated with all aspects of human development, in which derives the process of learning and desire to acquire knowledge and skill.Optic disc: The optic disc or optic nerve head is the point of exit for ganglion cell axons leaving the eye. BecauseLearning Plan: A Learning Plan is a document (possibly an interactive or on-line document) that is used to plan learning, usually over an extended period of time.Zhou Mi (badminton)Binocular vision: Binocular vision is vision in which creatures having two eyes use them together. The word binocular comes from two Latin roots, bini for double, and oculus for eye.Biological motion: Biological motion is a term used by social and cognitive neuroscientists to refer to the unique visual phenomenon of a moving, animate object. Often, the stimuli used in biological motion experiments are just a few moving dots that reflect the motion of some key joints of the moving organism.Gary H. Posner: Gary H. Posner (born c.Sensory decussation: The sensory decussation or decussation of the lemniscus is a decussation or crossover of axons from the gracile nucleus and cuneate nucleus, which are responsible for fine touch, proprioception and two-point discrimination of the body. The fibres of this decussation are called the internal arcuate fibres and are found at the superior aspect of the closed medulla superior to the motor decussation.VigabatrinRetinal regeneration: Retinal regeneration deals with restoring retinal function to vertebrates so impaired.Korte's law: In psychophysics, Korte's law, also known more completely as Korte's third law of apparent motion, is an observation relating the phenomenon of apparent motion to the distance and duration between two successively presented stimuli. It was originally proposed in 1915 by Adolf Korte.Blind People's Association: The Blind People’s Association (BPA) is an organisation in India which promotes comprehensive rehabilitation of persons with all categories of disabilities through education, training, employment, community based rehabilitation, integrated education, research, publications, human resource development and other innovative means.Hypervigilance: Hypervigilance is an enhanced state of sensory sensitivity accompanied by an exaggerated intensity of behaviors whose purpose is to detect threats. Hypervigilance is also accompanied by a state of increased anxiety which can cause exhaustion.Coherence theory: In physics, coherence theory is the study of optical effects arising from partially coherent light and radio sources. Partially coherent sources are sources where the coherence time or coherence length are limited by bandwidth, by thermal noise, or by other effect.Assay sensitivity: Assay sensitivity is a property of a clinical trial defined as the ability of a trial to distinguish an effective treatment from a less effective or ineffective intervention. Without assay sensitivity, a trial is not internally valid and is not capable of comparing the efficacy of two interventions.Macula of retina: The macula or macula lutea (from Latin macula, "spot" + lutea, "yellow") is an oval-shaped pigmented area near the center of the retina of the human eye. It has a diameter of around .Neuropathy, ataxia, and retinitis pigmentosaAvoidance reactionRhodesia at the 1968 Summer Paralympics: Rhodesia competed at the 1968 Summer Paralympics in Tel Aviv, Israel from 4 to 13 November 1968. The team ranked eleventh out of the twenty-eight competing nations in the medal table and won a total of twenty medals; six gold, seven silver and seven bronze.Vortex ring toyCerebral hemisphere: The vertebrate cerebrum (brain) is formed by two cerebral hemispheres that are separated by a groove, the medial longitudinal fissure. The brain can thus be described as being divided into left and right cerebral hemispheres.Nerve fiber layer: The retinal nerve fiber layer (nerve fiber layer, stratum opticum, RNFL) is formed by the expansion of the fibers of the optic nerve; it is thickest near the porus opticus, gradually diminishing toward the ora serrata.Electromagnetic environment: In telecommunication, the term electromagnetic environment (EME) has the following meanings:Low vision assessment: Low vision is both a subspeciality and a condition. Optometrists and Ophthalmologists after their training may undergo further training in Low vision assessment and management.HyperintensityOptic neuropathySaccade: A saccade ( , French for jerk) is quick, simultaneous movement of both eyes between two phases of fixation in the same direction.Cassin, B.Temporal analysis of products: Temporal Analysis of Products (TAP), (TAP-2), (TAP-3) is an experimental technique for studyingAnxiolytic: An anxiolytic (also antipanic or antianxiety agent) is a medication or other intervention that inhibits anxiety. This effect is in contrast to anxiogenic agents, which increase anxiety.Scanning laser ophthalmoscopyImbert-Fick law: The Imbert-Fick "law" was invented by Hans Goldmann (1899–1991) to give his newly marketed tonometer (with the help of the Haag-Streit Company) a quasi-scientific basis; it is mentioned in the ophthalmic and optometric literature, but not in any books of physics. According to Goldmann,Goldmann H.Respiratory compensation: Respiratory compensation is a mechanism by which plasma pH can be altered by varying the respiratory rate. It is faster than renal compensation, but has less ability to restore normal values.Hemispatial neglectPurtscher's retinopathy: Purtscher's retinopathy is a disease where part of the eye (retina) is damaged. Usually associated with severe head injuries, it may also occur with other types of trauma, such as long bone fractures, or with several non-traumatic systemic diseases.Cue stick: A cue stick (or simply cue, more specifically pool cue, snooker cue, or billiards cue), is an item of sporting equipment essential to the games of pool, snooker and carom billiards. It is used to strike a ball, usually the .Tadpole pupil: The eye is made up of the sclera, the iris, and the pupil, a black hole located at the center of the eye with the main function of allowing light to pass to the retina. Due to certain muscle spasms in the eye, the pupil can resemble a tadpole, which consists of a circular body, no arms or legs, and a tail.Rimless eyeglasses: Rimless eyeglasses, are a type of eyeglasses in which the lenses are mounted directly to the bridge and/or temples. The style is divided into two subtypes: three piece glasses are composed of lenses mounted to a bridge and two separate temple arms, while rimways (also called cortlands) feature a supporting arch that connects the temples to the bridge and provides extra stability for the lenses.Fixation reflex: The fixation reflex is that concerned with attracting the eye on a peripheral object. For example, when a light shines in the periphery, the eyes shift gaze on it.Cortical blindnessCanon EOS 5Amorphosynthesis: Amorphosynthesis is a medical condition where the patient is unaware of somatic sensations from one side of the body; the left side is most commonly affected. This condition is usually a sign of a lesion in the right parietal lobe.Outline of photography: The following outline is provided as an overview of and topical guide to photography:Optic nerve tumor: An optic nerve melanocytoma is a tumor made up of melanocytes and melanin. These tumors are typically a benign; they can grow, but rarely transform into a malignancy.Electrical impedance tomography: Electrical Impedance Tomography (EIT) is a non-invasive medical imaging technique in which an image of the conductivity or permittivity of part of the body is inferred from surface electrode measurements. Electrical conductivity depends on free ion content and differs considerably between various biological tissues (absolute EIT) or different functional states of one and the same tissue or organ (relative or functional EIT).Flicker (screen): Flicker is a visible fading between cycles displayed on video displays, especially the refresh interval on cathode ray tube (CRT) based computer screens. Flicker occurs on CRTs when they are driven at a low refresh rate, allowing the brightness to drop for time intervals sufficiently long to be noticed by a human eye – see persistence of vision and flicker fusion threshold.Pyrethroid: A pyrethroid is an organic compound similar to the natural pyrethrins produced by the flowers of pyrethrums (Chrysanthemum cinerariaefolium and C. coccineum).Spalding MethodGlare (vision): Glare is difficulty seeing in the presence of bright light such as direct or reflected sunlight or artificial light such as car headlamps at night. Because of this, some cars include mirrors with automatic anti-glare functions.PapilledemaMagnetic pulse welding: Magnetic pulse welding (MPW) is a solid state welding process that uses magnetic forces to weld two workpieces together. The welding mechanism is most similar to that of explosion welding.Autorefractor: An autorefractor or automated refractor is a computer-controlled machine used during an eye examination to provide an objective measurement of a person's refractive error and prescription for glasses or contact lenses. This is achieved by measuring how light is changed as it enters a person's eye.