query: blind spot is located in the area of the retina

pos: Blind spot (vision) The blind spot is located about 12–15° temporally and 1.5° below the horizontal and is roughly 7.5° high and 5.5° wide. Blind spot (vision) A blind spot, scotoma, is an obscuration of the visual field. A particular blind spot known as the "physiological blind spot", "blind point", or "punctum caecum" in medical literature, is the place in the visual field that corresponds to the lack of light-detecting photoreceptor cells on the optic disc of the retina where the optic nerve passes through the optic disc. Because there are no cells to detect light on the optic disc, the corresponding part

neg: Retina entire retina contains about 7 million cones and 75 to 150 million rods. The optic disc, a part of the retina sometimes called "the blind spot" because it lacks photoreceptors, is located at the optic papilla, where the optic-nerve fibres leave the eye. It appears as an oval white area of 3 mm². Temporal (in the direction of the temples) to this disc is the macula, at whose centre is the fovea, a pit that is responsible for our sharp central vision but is actually less sensitive to light because of its lack of rods. Human and non-human primates possess

neg: Retina damage and allows the photoreceptor cells to have decades-long useful lives. The bird retina is devoid of blood vessels, perhaps to give unobscured passage of light for forming images, thus giving better resolution. It is, therefore, a considered view that the bird retina depends for nutrition and oxygen supply on a specialized organ, called the "pecten" or pecten oculi, located on the blind spot or optic disk. This organ is extremely rich in blood vessels and is thought to supply nutrition and oxygen to the bird retina by diffusion through the vitreous body. The pecten is highly rich in alkaline

neg: Blind spot (vision) Blind spot (vision) A blind spot, scotoma, is an obscuration of the visual field. A particular blind spot known as the "physiological blind spot", "blind point", or "punctum caecum" in medical literature, is the place in the visual field that corresponds to the lack of light-detecting photoreceptor cells on the optic disc of the retina where the optic nerve passes through the optic disc. Because there are no cells to detect light on the optic disc, the corresponding part of the field of vision is invisible. Some process in our brains interpolates the blind spot based on surrounding detail and

neg: Blind spot (vision) information from the other eye, so we do not normally perceive the blind spot. Although all vertebrates have this blind spot, cephalopod eyes, which are only superficially similar, do not. In them, the optic nerve approaches the receptors from behind, so it does not create a break in the retina. The first documented observation of the phenomenon was in the 1660s by Edme Mariotte in France. At the time it was generally thought that the point at which the optic nerve entered the eye should actually be the most sensitive portion of the retina; however, Mariotte's discovery disproved this theory.

neg: Visual prosthesis type of visual implant that has met with some success in the treatment of end-stage age-related macular degeneration. This type of device is implanted in the eye's posterior chamber and works by increasing (by about three times) the size of the image projected onto the retina in order to overcome a centrally located scotoma or blind spot. Created by VisionCare Ophthalmic Technologies in conjunction with the CentraSight Treatment Program, the telescope is about the size of a pea and is implanted behind the iris of one eye. Images are projected onto healthy areas of the central retina, outside the degenerated

neg: Retina is the only part of the CNS that can be visualized non-invasively. The vertebrate retina is "inverted" in the sense that the light sensing cells are in back of the retina, so that light has to pass through layers of neurons and capillaries before it reaches the rods and cones. In contrast, in the cephalopod retina the photoreceptors are in front, with processing neurons and capillaries behind them. Because of this, cephalopods do not have a blind spot. The overlying neural fibre layer does not degrade vision in the inverted retina. The neurons are transparent and the accompanying glial cells

neg: Filling-in Filling-in In vision, filling-in phenomena are those responsible for the completion of missing information across the physiological blind spot, and across natural and artificial scotomata. There is also evidence for similar mechanisms of completion in normal visual analysis. Classical demonstrations of perceptual filling-in involve filling in at the blind spot in monocular vision, and images stabilized on the retina either by means of special lenses, or under certain conditions of steady fixation. For example, naturally in monocular vision at the physiological blind spot, the percept is not a hole in the visual field, but the content is “filled-in” based on

neg: Form perception information of the stimulus. Form perception is a demanding task for the brain because a retina has a significant blind spot and retinal veins that obstruct light from reaching cells that detect light, or photoreceptor cells. The brain handles the blind spots through boundary processes, includes perceptual grouping, boundary completion, and figure-ground separation, and through surface processing, including compensation for variable illumination (“discounting the illuminant”), and filling blank areas with the surviving illuminant-discounted signals. In addition to photoreceptors, the eye requires a properly functioning lens, retina, and an undamaged optic nerve to recognize form. Light travels through the lens, hits

neg: Sergey Kravkov (psychologist) bioelectricity of different levels of visual system (retina, cerebral subcortex and cortex), interaction of macular and peripheral spheres of the retina, induction of retina, electrophysiology of the eyesight (electric sensibility of the eye, lability, electroretinogram), colour eyesight and its anomalies, sensorial classical conditioning, glaucoma diagnosis methods (by colour sensation and by the reaction of a blind spot) and many other items. Kravkov is one of the founders of physiological optics, a scientific discipline representing a synthesis of knowledge about physiological, psychical and psychological regularities that characterize the function of the eyesight organ. He studied the regularities of the functioning of

neg: Eye cells used for vision: the rods and the cones. Rods cannot distinguish colours, but are responsible for low-light (scotopic) monochrome (black-and-white) vision; they work well in dim light as they contain a pigment, rhodopsin (visual purple), which is sensitive at low light intensity, but saturates at higher (photopic) intensities. Rods are distributed throughout the retina but there are none at the fovea and none at the blind spot. Rod density is greater in the peripheral retina than in the central retina. Cones are responsible for colour vision. They require brighter light to function than rods require. In humans, there are

neg: Optic disc drusen retinal ganglion cell axons. The optic nerve head, or optic disc is the anterior end of the nerve that is in the eye and hence is visible with an ophthalmoscope. It is located nasally and slightly inferior to the macula of the eye. There is a blind spot at the optic disc because there are no rods or cones beneath it to detect light. The central retinal artery and vein can be seen in the middle of the disc as it exits the scleral canal with the optic nerve to supply the retina. The vessels send branches out in all

neg: Scotoma Scotoma A scotoma (Greek σκότος/"skótos", "darkness"; plural: "scotomas" or "scotomata") is an area of partial alteration in the field of vision consisting of a partially diminished or entirely degenerated visual acuity that is surrounded by a field of normal – or relatively well-preserved – vision. Every normal mammal eye has a scotoma in its field of vision, usually termed its blind spot. This is a location with no photoreceptor cells, where the retinal ganglion cell axons that compose the optic nerve exit the retina. This location is called the optic disc. There is no direct conscious awareness of visual scotomas.

neg: Caecobarbus geertsii reduced pigmentation and no externally visible eyes. Because of the lack of pigment, it appears pale whitish-pink overall. The operculum and lateral line region are purplish-red due to the gills and lateral line veins, respectively. The eye completely lacks a lens, and the retina and optical nerve are rudimentary and located deep inside the head. Despite this the fish is photophobic, actively avoiding light. Its maximum length is . Minor differences have been described between the different cave populations; some have a spot on the opercular and one has a serrated dorsal fin spine. The Congo blind barb mainly relies

neg: Collie eye anomaly as an autosomal recessive trait that has a penetrance reaching 100 percent, and has been localized to canine chromosome 37. The most common sign of CEA is the presence of an area of undeveloped choroid (appearing as a pale spot) lateral to the optic disc. The choroid is a collection of blood vessels supplying the retina. CEA can also cause retinal or scleral coloboma, coloboma of the optic disc, retinal detachment, or intraocular hemorrhage. It can be diagnosed by fundoscopy by the age of six or seven weeks. Severe cases may be blind. Controversies exist around eliminating this disorder from

neg: Cup-to-disc ratio large cup-to-disc ratio may imply glaucoma or other pathology. However, cupping by itself is not indicative of glaucoma. Rather, it is an increase in cupping as the patient ages that is an indicator for glaucoma. Deep but stable cupping can occur due to hereditary factors without glaucoma. Cup-to-disc ratio The cup-to-disc ratio (often notated CDR) is a measurement used in ophthalmology and optometry to assess the progression of glaucoma. The optic disc is the anatomical location of the eye's "blind spot", the area where the optic nerve and blood vessels enter the retina. The optic disc can be flat or

neg: Cup-to-disc ratio Cup-to-disc ratio The cup-to-disc ratio (often notated CDR) is a measurement used in ophthalmology and optometry to assess the progression of glaucoma. The optic disc is the anatomical location of the eye's "blind spot", the area where the optic nerve and blood vessels enter the retina. The optic disc can be flat or it can have a certain amount of normal cupping. But glaucoma, which is in most cases associated with an increase in intraocular pressure, often produces additional pathological cupping of the optic disc. The pink rim of disc contains nerve fibers. The white cup is a pit with

neg: Cuttlefish of light, which enhances their perception of contrast. They have two spots of concentrated sensor cells on their retinas (known as foveae), one to look more forward, and one to look more backward. The eye changes focus by shifting the position of the entire lens with respect to the retina, instead of reshaping the lens as in mammals. Unlike the vertebrate eye, no blind spot exists, because the optic nerve is positioned behind the retina. This allows cuttlefish to see in front of them and behind them at the same time. The cuttlefish's eyes are thought to be fully developed

neg: Neural correlates of consciousness is unclear what adaptive advantage consciousness could provide. As a result, an exaptive explanation of consciousness has gained favor with some theorists that posit consciousness did not evolve as an adaptation but was an exaptation arising as a consequence of other developments such as increases in brain size or cortical rearrangement. Consciousness in this sense has been compared to the blind spot in the retina where it is not an adaption of the retina, but instead just a by-product of the way the retinal axons were wired. Several scholars including Pinker, Chomsky, Edelman, and Luria have indicated the importance of

neg: Laser safety light onto a tiny spot on the retina. Light sources with a smaller degree of spatial coherence than a well-collimated laser beam, such as high-power LEDs, lead to a distribution of the light over a larger area on the retina. For such sources, the MPE is higher than for collimated laser beams. In the MPE calculation, the worst-case scenario is assumed, in which the eye lens focuses the light into the smallest possible spot size on the retina for the particular wavelength and the pupil is fully open. Although the MPE is specified as power or energy per unit surface,

neg: Tay–Sachs disease retina, easily observable by a physician using an ophthalmoscope. This red spot is a retinal area that appears red because of gangliosides in the surrounding retinal ganglion cells. The choroidal circulation is showing through "red" in this foveal region where all retinal ganglion cells are pushed aside to increase visual acuity. Thus, this cherry-red spot is the only normal part of the retina; it shows up in contrast to the rest of the retina. Microscopic analysis of the retinal neurons shows they are distended from excess ganglioside storage. Unlike other lysosomal storage diseases (e.g., Gaucher disease, Niemann–Pick disease, and Sandhoff

neg: Consciousness the very same survival advantages as a conscious organism. If evolutionary processes are blind to the difference between function "F" being performed by conscious organism "O" and non-conscious organism "O*", it is unclear what adaptive advantage consciousness could provide. As a result, an exaptive explanation of consciousness has gained favor with some theorists that posit consciousness did not evolve as an adaptation but was an exaptation arising as a consequence of other developments such as increases in brain size or cortical rearrangement. Consciousness in this sense has been compared to the blind spot in the retina where it is not

neg: Optics first through the cornea, which provides much of the eye's optical power. The light then continues through the fluid just behind the cornea—the anterior chamber, then passes through the pupil. The light then passes through the lens, which focuses the light further and allows adjustment of focus. The light then passes through the main body of fluid in the eye—the vitreous humour, and reaches the retina. The cells in the retina line the back of the eye, except for where the optic nerve exits; this results in a blind spot. There are two types of photoreceptor cells, rods and cones,

neg: Convergent evolution evolution is the camera eye of cephalopods (such as squid and octopus), vertebrates (including mammals) and cnidaria (such as jellyfish). Their last common ancestor had at most a simple photoreceptive spot, but a range of processes led to the progressive refinement of camera eyes — with one sharp difference: the cephalopod eye is "wired" in the opposite direction, with blood and nerve vessels entering from the back of the retina, rather than the front as in vertebrates. As a result, cephalopods lack a blind spot. Birds and bats have homologous limbs because they are both ultimately derived from terrestrial tetrapods,

neg: Blind spot monitor keep the vehicle from colliding. Blind spot monitor The blind spot monitor is a vehicle-based sensor device that detects other vehicles located to the driver’s side and rear. Warnings can be visual, audible, vibrating, or tactile. However, blind spot monitors are an option that may do more than monitor the sides and rear of the vehicle. They may also include "Cross Traffic Alert", "which alerts drivers backing out of a parking space when traffic is approaching from the sides." If side view mirrors on a car are adjusted in a particular way, there is no blind spot on the sides.

neg: Blind spot monitor Blind spot monitor The blind spot monitor is a vehicle-based sensor device that detects other vehicles located to the driver’s side and rear. Warnings can be visual, audible, vibrating, or tactile. However, blind spot monitors are an option that may do more than monitor the sides and rear of the vehicle. They may also include "Cross Traffic Alert", "which alerts drivers backing out of a parking space when traffic is approaching from the sides." If side view mirrors on a car are adjusted in a particular way, there is no blind spot on the sides. This method was first revealed

neg: Blind spot monitor to this recognized problem. BLIS is an acronym for "Blind Spot Information System", a system of protection developed by Volvo. Volvo's previous parent, Ford Motor Company, has since adapted the system to its Ford, Lincoln, and Mercury brands. This system was first introduced on the redesigned 2007 Volvo S80 sedan and produced a visible alert when a car entered the blind spot while a driver was switching lanes, using two door mounted lenses to check the blind spot area for an impending collision. Mazda was the first Japanese automaker to offer a blind spot monitor, which they refer to as

neg: Vehicle blind spot Vehicle blind spot A blind spot in a vehicle is an area around the vehicle that cannot be directly observed by the driver while at the controls, under existing circumstances. Blind spots exist in a wide range of vehicles: aircraft, cars, motorboats, sailboats, and trucks. Other types of transport have no blind spots at all, such as bicycles, horses, and motorcycles. Proper adjustment of mirrors and use of other technical solutions can eliminate or alleviate vehicle blind spots. A no zone is one of several areas around a large truck, where the truck driver cannot see. Collisions frequently occur in

neg: Vehicle blind spot the front of the vessel to cover the missing field of view. Blind spots exist where areas behind the sail are obscured from the view of a helmsman on a sailboat or windsurfer. This is especially true when they are heeled over; consequently, transparent windows are sometimes sewn into the sails. Vehicle blind spot A blind spot in a vehicle is an area around the vehicle that cannot be directly observed by the driver while at the controls, under existing circumstances. Blind spots exist in a wide range of vehicles: aircraft, cars, motorboats, sailboats, and trucks. Other types of transport

neg: Blind Spot (Beverly Hills, 90210) a date between Donna and recurring African-American character D'Shawn Hardell. In partnership with the Los Angeles chapter of the Gay & Lesbian Alliance Against Defamation, the producers of "Beverly Hills, 90210" sponsored screenings of "Blind Spot" at three gay and lesbian youth centers in the Los Angeles area. Following each screening, executive producer Chuck Rosin and guest star Todd Bryant participated in a question-and-answer session. Blind Spot (Beverly Hills, 90210) "Blind Spot" is a 1994 episode of the American television series "Beverly Hills, 90210". The episode follows two stories. In the first, series regular David Silver finds himself attracted to

neg: Optic disc Optic disc The optic disc or optic nerve head is the point of exit for ganglion cell axons leaving the eye. Because there are no rods or cones overlying the optic disc, it corresponds to a small blind spot in each eye. The ganglion cell axons form the optic nerve after they leave the eye. The optic disc represents the beginning of the optic nerve and is the point where the axons of retinal ganglion cells come together. The optic disc is also the entry point for the major blood vessels that supply the retina. The optic disc in a

neg: UM Motorcycles the helmet to communicate via Bluetooth with the UM Motorcycle. KAS (Keyless Alarm System) is a system to recognise the UM bike owner's presence within 1.2 metres of the bike, and subsequently start the bike without a key. BSM (Blind Spot Mirror System) is a system where the rear view mirrors have a section on the outer corner with a blind spot mirror, allowing the rider to spot vehicles in the blind spot area. UM Motorcycles UM-Motorcycles (United Motors) is an American motorcycle manufacturer headquartered in Miami. UM was formed in the early 2000s by Octavio Villegas Llano. The company

neg: Cyborg use of electronic stimulation of the retina to allow the eye to sense patterns of light. A specialized camera is worn by the subject, such as on the frames of their glasses, which converts the image into a pattern of electrical stimulation. A chip located in the user's eye would then electrically stimulate the retina with this pattern by exciting certain nerve endings which transmit the image to the optic centers of the brain and the image would then appear to the user. If technological advances proceed as planned this technology may be used by thousands of blind people and

neg: Optic disc patients without glaucoma. Optic disc The optic disc or optic nerve head is the point of exit for ganglion cell axons leaving the eye. Because there are no rods or cones overlying the optic disc, it corresponds to a small blind spot in each eye. The ganglion cell axons form the optic nerve after they leave the eye. The optic disc represents the beginning of the optic nerve and is the point where the axons of retinal ganglion cells come together. The optic disc is also the entry point for the major blood vessels that supply the retina. The optic

neg: Topographic map (neuroanatomy) damaged that individual would then have a blind spot in the real world, they would not be able to see the bit of the world that corresponded to the retina damage. Orientation maps are also topographic. In these maps there are cells which have a preference to a certain orientation, the maximum firing rate of the cell will be achieved at that preference. As the orientation is moved away from the firing rate will drop. An orientation map is topographic because neighboring neural tissues have similar orientation preferences. The term "retinotopic" refers to the maintenance of the particular order of

neg: Vitrectomy it. Often diabetic retinopathy is treated in early stages with a laser in the physician's office to prevent these problems. When bleeding or retinal detachment occur, vitrectomy is employed to clear the blood, membranectomy removes scar tissue, and injection of gas or silicone with scleral buckle may be needed to return sight. Diabetics should have an eye exam yearly. Macular holes – the normal shrinking of the vitreous humor with aging can occasionally tear the central retina causing a macular hole with a blind spot blocking sight. Vitreous hemorrhage – bleeding in the eye from injuries, retinal tears, subarachnoid hemorrhages

neg: Lilac chaser that appear larger because of Emmert's law: the size of an afterimage becomes larger as its viewing distance is increased. They are outside because moving away from the computer screen has decreased the visual angle of the lilac spots. They fade because the lilac discs that constantly refresh the green afterimages are now projected onto a different part of the retina. If one moves towards the screen, the effects are opposite. If one closes the right eye and moves close to the stimulus so that the nine-o'clock disc falls in the blind spot, one sees that the movement is no

neg: Non-24-hour sleep–wake disorder in the retina are also removed. Without light to the retina, the suprachiasmatic nucleus (SCN), located in the hypothalamus, is not cued each day to synchronize the circadian rhythm to the 24-hour social day, resulting in non-24 for many totally blind individuals. Non-24 is rare among visually impaired patients who retain at least some light perception. Researchers have found that even minimal light exposure at night can affect the body clock. People with this disorder might find it difficult to follow a regular clock scheme, as their biological clock can shift so much that they are sleepy during the day

neg: Filling-in that a real spreading of neural activity in early visual areas is the basis for filling-in of visual information. Komatsu and colleagues (Komatsu et al., 2000) recorded activity of cells of the blind spot representation in monkey striate cortex (area V1) and found some cells, in layers 4–6, that responded to large stimuli covering the blind spot (the condition under which filling-in is perceived), but not to small stimuli near the blind spot. A neuronal circuitry seems to exist that elaborates and transmits colour and brightness information through the blind region. Though intriguing, these results cannot be easily generalized to

neg: Adaptationism characteristics which become modified by natural selection of mutant phenotypes, it is as if some are traits are locked in place and are unable to change in certain ways. Some textbook anatomical constraints often include examples of structures that connect parts of the body together though a physical link. These links are hard if not impossible to break because evolution usually requires that anatomy be formed by small consecutive modifications in populations through generations. In his book, "Why We Get Sick", Randolph Nesse uses the "blind spot" in the vertebrate eye (caused by the nerve fibers running through the retina)

neg: Laser safety their eyesight. A pop or click noise emanating from the eyeball may be the only indication that retinal damage has occurred i.e. the retina was heated to over 100 °C resulting in localized explosive boiling accompanied by the immediate creation of a permanent blind spot. Lasers can cause damage in biological tissues, both to the eye and to the skin, due to several mechanisms. Thermal damage, or burn, occurs when tissues are heated to the point where denaturation of proteins occurs. Another mechanism is photochemical damage, where light triggers chemical reactions in tissue. Photochemical damage occurs mostly with short-wavelength (blue

neg: Distorted vision vision. Some people may think that these sparks are floaters. In reality, they represent white blood cells moving through the blood capillaries of the retina. This is a normal finding, and actually may indicate normal retinal function. Migraine headaches may be preceded by a visual "aura", lasting for 20 to 30 minutes, and then proceeding to the headache. Some people, however, experience the aura but do not have a headache. This visual aura can be very dramatic. Classically, a small blind spot appears in the central vision with a shimmering, zig-zag light inside of it. This enlarges, and moves to

neg: Lilac chaser longer smooth. There is a noticeable pause when the disappearance of the disc occurs on the region of the retina having no rods or cones. This suggests there are limits to the filling-in that normally prevents us from noticing a black hole in our visual fields at the location of the blind spot. Lilac chaser The lilac chaser is a visual illusion, also known as the Pac-Man illusion. It consists of 12 lilac (or pink, rose, or magenta), blurred discs arranged in a circle (like the numbers on a clock), around a small black, central cross on a grey background.

neg: Evolutionary developmental biology exactly matches an eye-forming gene in mice and humans. The same gene was quickly found in many other groups of animals, such as squid, a cephalopod mollusc. Biologists including Ernst Mayr had believed that eyes had arisen in the animal kingdom at least 40 times, as the anatomy of different types of eye varies widely. For example, the fruit fly's compound eye is made of hundreds of small lensed structures (ommatidia); the human eye has a blind spot where the optic nerve enters the eye, and the nerve fibres run over the surface of the retina, so light has to

neg: Macula of retina example in macular degeneration. The clinical macula is seen when viewed from the pupil, as in ophthalmoscopy or retinal photography. The term macula lutea comes from Latin "macula", "spot", and "lutea", "yellow". The macula is an oval-shaped pigmented area near the center of the retina of the human eye and some other animalian eyes. The macula in humans has a diameter of around and is subdivided into the umbo, foveola, foveal avascular zone, fovea, parafovea, and perifovea areas. The anatomical macula at is much larger than the clinical macula which, at , corresponds to the anatomical fovea. The clinical macula

neg: Expert age, handedness, and season of birth. In the field of education there is a potential "expert blind spot" (see also Dunning–Kruger effect) in newly practicing educators who are experts in their content area. This is based on the "expert blind spot hypothesis" researched by Mitchell Nathan and Andrew Petrosino (2003: 906). Newly practicing educators with advanced subject-area expertise of an educational content area tend to use the formalities and analysis methods of their particular area of expertise as a major guiding factor of student instruction and knowledge development, rather than being guided by student learning and developmental needs that are

neg: Scotoma and may be of any shape or size. A scotoma may include and enlarge the normal blind spot. Even a small scotoma that happens to affect central or macular vision will produce a severe visual disability, whereas a large scotoma in the more peripheral part of a visual field may go unnoticed by the bearer because of the normal reduced optical resolution in the peripheral visual field. Common causes of scotomata include demyelinating disease such as multiple sclerosis (retrobulbar neuritis), damage to nerve fiber layer in the retina (seen as cotton wool spots) due to hypertension, toxic substances such as

neg: Parasol cell the first step in the magnocellular pathway of the visual system. They project from the retina via the optic nerve to the two most ventral layers of the lateral geniculate nucleus of the thalamus, to the magnocellular cells. Eventually, the information these cells collect in the retina is sent to various parts of the visual cortex, including the posterior parietal cortex and area V5 through the dorsal stream, and the inferior temporal cortex and area V4 through the ventral stream. Parasol ganglion cells are located in the retina of the eyes, and make up roughly 10% of all retinal ganglion

neg: Bias blind spot spot is not related to actual decision-making ability. Participants who scored better or poorer on various tasks associated with decision making competence were no more or less likely to be higher or lower in their susceptibility to bias blind spot. Bias blind spot does, however, appear to increase susceptibility to related biases. People who are high in bias blind spot are more likely to ignore the advice of other people, and are less likely to benefit from training geared to reduce their commission of other biases. Bias blind spot The bias blind spot is the cognitive bias of recognizing the

neg: Baffles (submarine) sounds, it must be protected from the noise generated by machinery on the vessel on which the sonar is installed. Otherwise, its own noise would tend to drown out other sonar targets. To reduce noise, sound-attenuating material is placed between the sonar and the rest of the vessel. This makes the sonar much more effective, but causes a blind spot where this material is: as most hull-mounted sonars are located at the front of the vessel, the resulting blind spot is located directly behind the vessel. The term baffles is likely derived from a lesser used definition of the word

neg: Briard into an electrical signal that travels to the brain. When the photoreceptor cells deteriorate, vision is lost because the animal has no way to generate an image from the light reaching the retina. Puppies are usually blind before one year of age. For the first time ever, animals (Briards) that were born blind gained the ability to see after undergoing gene therapy, according to research from the University of Florida, Cornell University and the University of Pennsylvania. UF researchers had established that the apparently harmless adeno-associated virus can carry healthy copies of a gene into the cells of the retina,

neg: Robert MacLaren to (Professor) James Bainbridge and helped perform the world's first retinal gene therapy treatment. The operation was carried out at Moorfields in London. The patient was Mr. Robert Johnson, a young man with Leber's Congenital Amaurosis (LCA). A faulty gene in the pigment layer, RPE65, prevented his photoreceptor cells from working, so a valid copy of the gene was implanted in one eye to 'patch' the blind-spot and restore function. The delicate operation required passing a needle through the eye, to lift the retina and insert the new gene-copy in the pigment layer. This trial was funded by the Health

neg: Bias blind spot Bias blind spot The bias blind spot is the cognitive bias of recognizing the impact of biases on the judgment of others, while failing to see the impact of biases on one's own judgment. The term was created by Emily Pronin, a social psychologist from Princeton University's Department of Psychology, with colleagues Daniel Lin and Lee Ross. The bias blind spot is named after the visual blind spot. Most people appear to exhibit the bias blind spot. In a sample of more than 600 residents of the United States, more than 85% believed they were less biased than the average

neg: Visual impairment incapable people leading other incapable people. Being blind to something means not understanding or being aware of it. A "blind spot" is an area where someone cannot see: for example, where a car driver cannot see because parts of his car's bodywork are in the way; metaphorically, a topic on which an individual is unaware of their own biases, and therefore of the resulting distortions of their own judgements (see Bias blind spot). A 2008 study tested the effect of using gene therapy to help restore the sight of patients with a rare form of inherited blindness, known as Leber's

neg: Vehicle blind spot and size restraints pertaining to aerodynamics, as taller, more vertical windshields create additional drag and reduce fuel efficiency. They also include fashion and cost, whereby design and appearance considerations can be deemed preeminent. This system was first introduced in the Volvo S80 sedan and produced a visible alert when a car entered the blind spot while a driver was switching lanes, using two door mounted lenses to check the blind spot area for an impending collision. On Ford products, the system was first introduced in the spring of 2009 on the 2010 Ford Fusion and Fusion Hybrid, 2010 Mercury Milan

neg: Brodmann area 19 V4, V5 (also known as the middle temporal area, or MT), and V6 (also known as dorsomedial area) in the primate. Functional magnetic resonance imaging shows the existence of various retinotopic maps within area 19. In general, the diverse fields that comprise area 19 have reciprocal connections with areas 17 and 18, as well as posterior parietal and inferior temporal association areas. Area 19 has been noted to receive inputs from the retina via the superior colliculus and pulvinar, and may contribute to the phenomenon of blindsight. In patients blind from a young age, the area has been found to

neg: Prosimian are New World monkeys of genus "Aotus"). Related to their frequently nocturnal lifestyle, prosimians lack the colour vision of higher primates. Like most placental mammals, they are in effect red–green colour blind. This allows for more rod cells in the retina, which may enhance vision under low-light conditions. Except in tarsiers, the nocturnal vision is further augmented by a reflective tapetum lucidum behind the retina, similar to that found in other nocturnal mammals. This layer reflects the light that passes through the retina, increasing the photoreceptors exposure to the light. It is however not well developed in diurnal forms like

neg: Bias blind spot American. Only one participant believed that he or she was more biased than the average American. People do vary with regard to the extent to which they exhibit the bias blind spot. It appears to be a stable individual difference that is measurable (for a scale, see Scopelliti et al. 2015). The bias blind spot appears to be a true blind spot in that it is unrelated to actual decision making ability. Performance on indices of decision making competence are not related to individual differences in bias blind spot. In other words, everyone seems to think they are less biased

neg: Blind artists she is literally painting sight, giving a new perspective on sight loss. There are many organizations around the world that offer assistance to the blind. There are also some that offer assistance and support specifically for blind artists. One example of these organizations in the United States is the Blind Artists Society, a support group for visually impaired amateur artists. Founded in 2007, the organization is funded by the Retina Research Foundation and seeks to provide an environment where artists can gather to display and sell their art, communicate with other artists and receive support. The organization also organizes periodic

neg: Blind Spot (Beverly Hills, 90210) Blind Spot (Beverly Hills, 90210) "Blind Spot" is a 1994 episode of the American television series "Beverly Hills, 90210". The episode follows two stories. In the first, series regular David Silver finds himself attracted to his blind piano teacher, causing a strain on his relationship with girlfriend Donna Martin. In the second, series regular Steve Sanders discovers that Mike Ryan, the president of his college fraternity, is gay, and outs him to the rest of the fraternity. The 26th episode of season 4, "Blind Spot" originally aired on April 6, 1994. David Silver (Brian Austin Green) is having trouble practicing

neg: University of Toronto Mississauga numerous other student clubs. The Blind Duck Pub, located in The Student Centre, is popular eating spot on campus where students and staff are able to socialize. The menu includes chicken wings, halal meats, vegetarian dishes, French fries and more. The Blind Duck Pub also hosts many student events including the First Pub, Last Pub, and Halloween Pub where various artists such as Shawn Desman and Mia Martina perform. Students can find on-campus employment opportunities at the Blind Duck Pub as it is owned and operated by the UTM Student Union. The Recreation Athletic and Wellness Centre (RAWC), located in

neg: South Asian river dolphin the dolphin effectively blind, but the eye may still serve as a light receptor. The retina contains a densely packed receptor layer, a very thin bipolar and ganglion cell layer, and a tiny optic nerve (with only a few hundred optic fibers) that are sufficient for the retina to act as a light-gathering component. The dense pigmentation in the skin overlying the eye prevents light from reaching the retina from any entrance except for a pinhole sphincter-like structure. This structure is controlled by a cone-shaped muscle layer that extends from the posterior eye orbit to the overlying eye skin layer.

neg: Baffles (submarine) Baffles (submarine) The baffles is the area in the water directly behind a submarine or ship through which a hull-mounted sonar cannot hear. This blind spot is caused by the need to insulate the sonar array, commonly mounted near the bow, from the noise of the vessel's machinery. During the Cold War, one submarine would frequently attempt to follow another by hiding in its baffles. This led to the practice of "clearing the baffles", that is, turning to observe the blind spot and detect any followers. Related maneuvers included the "Crazy Ivan", a hard turn to clear the baffles and

neg: Antenna blind cone profiling such multi-level scanning is meant to provide. Thus, a weather event located very close to and/or directly overhead of the radar site will be mostly situated in the "cone of silence." This is part of the reason why most U.S. weather radars partially overlap each other's territories. Antenna blind cone In telecommunications, antenna blind cone (sometimes called a cone of silence or antenna blind spot) is the volume of space, usually approximately conical with its vertex at the antenna, that cannot be scanned by an antenna because of limitations of the antenna radiation pattern and mount. An Air Route

neg: Misha Mahowald Caltech as a PhD student in Computation and Neural Systems under the supervision of Professor Carver Mead, a specialist in computer science. For her thesis, Mahowald created her own project by combining the fields of biology, computer science, and electrical engineering, to produce the silicon retina. The silicon retina used analog electrical circuits to mimic the biological functions of rod cells, cone cells, and other non-photoreceptive cells in the retina of the eye. The invention was not only highly original and potentially useful as a device for restoring sight to the blind, but it was also one of the most

neg: Retinal precursor cells retina is generated from the precursor cells within the inner layer of the optic cup, as opposed to the retinal pigment epithelium that originate from the outer layer of the optic cup. In general, the developing retina is organized so that the least-committed precursor cells are located in the periphery of the retina, while the committed cells are located in the center of the retina. The differentiation of retinal precursor cells into the mature cell types found in the retina is coordinated in time and space by factors within the cell as well as factors in the environment of the

neg: Modrac Lake lake to function properly for the people that turned off the traditional swimming area, and also causing tourists to lose interest. A cable car for goods transport crosses Modrac Lake. Modrac Lake Modrac Lake (Bosnian: Jezero Modrac) is an artificial lake of Bosnia and Herzegovina. It is located in the municipality of Lukavac. Modrac Lake, as of this very day, is an attractive location to fishermen. Consisting a lot of species of fish, later in the year of 2005, it became a tourist attraction but initially became a blind spot because of the bad influence from the local government and

neg: Scintillating scotoma remains normal beyond the borders of the expanding scotoma(s), with objects melting into the scotoma area background similarly to the physiological blind spot, which means that objects may be seen better by not looking directly at them in the early stages when the spot is in or near the center. The scotoma area may expand to completely occupy one half of the visual area, or it may also be bilateral. It may occur as an isolated symptom without headache in acephalgic migraine. As the scotoma area expands, some people perceive only a bright flickering area that obstructs normal vision, while

neg: Visual cortex lower bank of the calcarine to the upper half of visual field. In concept, this retinotopic mapping is a transformation of the visual image from retina to V1. The correspondence between a given location in V1 and in the subjective visual field is very precise: even the blind spots are mapped into V1. In terms of evolution, this correspondence is very basic and found in most animals that possess a V1. In humans and animals with a fovea in the retina, a large portion of V1 is mapped to the small, central portion of visual field, a phenomenon known as

neg: Blind Spot (Homeland) directed by Clark Johnson, his first of the two episodes he directed for the first season. The original broadcast had 1.28 million viewers, which was an increase of 180,000 viewers over the previous episode. Todd VanDerWerff of The A.V. Club gave "Blind Spot" a grade of A, and declared "Homeland’s not just the best new show of the season; it’s the best show currently airing on TV". Jesse Carp of Cinema Blend thought the interrogation scene was "one of the most memorable in an already unforgettable series". Blind Spot (Homeland) "Blind Spot" is the fifth episode of the first season

neg: Blind Spot (1958 film) Adams realises that a pilot thought to be dead is really Johnny Brent (Michael Caine) who knows more about the theft and murders. Finally unravelling the mysterious death and smuggling operation, Adams proves his innocence. Principal location photography for "Blind Spot" took place at Majestic Hotel, Kensington, London, England. Studio shots were completed at Walton Studios, Walton-on-Thames, Surrey, England. Blind Spot is a remake of "Blackout", a British crime drama (1950 film), by the same producers, but a different director. "TV Guide" gave "Blind Spot" one out of four stars, and wrote, "A few good turns, including the final chase,

neg: Cortical stimulation mapping research because it targets neurons past the site of disease in most blind patients. However, significant challenges remain such as reproducibility in different patients, long-term effects of electrical stimulation, and the higher complexity of visual organization in the primary visual cortex versus that in the retina. Another site of research for a vision prosthesis using cortical stimulation is the optic nerve itself, which contains the nerve fibers responsible for the complete visual field. Research is still ongoing in this area and the small size of the optic nerve and the high density of nerve fibers are continuing challenges to this

neg: Cybernetics: Or Control and Communication in the Animal and the Machine also explores the various feedback loops involved in the operation of the eyes: the homeostatic operation of the retina to control light levels, the adjustment of the lens to bring objects into focus, and the complex set of reflex movements to bring an object of attention into the detailed vision area of the fovea. The chapter concludes with an outline of the challenges presented by attempts to implement a reading machine for the blind. Wiener opens this chapter with the disclaimers that he is neither a psychopathologist nor a psychiatrist, and that he is not asserting that mental problems are

neg: Blind Spot Pictures Most recently, Blind Spot Pictures produced the film "Iron Sky" for Timo Vuorensola, as a dark science fiction comedy about Nazis on the moon. They also have several features in development, including pre-production on Antti-Jussi Annila's werewolf inversion titled "Human", and the "Iron Sky" sequel "". In 2012, "Iron Sky" director Vuorensola joined as partner with the company. Blind Spot Pictures Blind Spot Pictures Oy is a Finnish production company established in 1997 by ACE-producer Tero Kaukomaa to produce and co-produce feature-films for international markets. Completed films include the Finnish/Chinese kung-fu film "Jade Warrior" by Antti-Jussi Annila, "Man's Job" by

neg: Blind Spot Pictures Blind Spot Pictures Blind Spot Pictures Oy is a Finnish production company established in 1997 by ACE-producer Tero Kaukomaa to produce and co-produce feature-films for international markets. Completed films include the Finnish/Chinese kung-fu film "Jade Warrior" by Antti-Jussi Annila, "Man's Job" by Aleksi Salmenperä, "Dancer in the Dark" by Lars von Trier (Zentropa / Denmark), "The Rainbowmaker" by Oscar nominated Nana Djordjadze, and "A Rational Solution" by Jörgen Bergmark, as well as the Golden Globe nominee "Everlasting Moments" by Jan Troell. Blind Spot Pictures has been co-producing with countries like China, Denmark, Estonia, Germany, Holland, UK, Italy, Sweden and Russia.

neg: Vehicle blind spot and Milan Hybrid and 2010 Lincoln MKZ and Mazda 6. This technology was also introduced on the 2010 Mazda CX-9 Grand Touring model. Some newer and more costly systems use side radar offering better performance and also warn of fast approaching vehicles entering the blind spot. Blind spots also exist in front of boats. When the boat accelerates, the bow rises, increasing the size of the blind spot. Large vessels can have up to several hundreds of meters of blind spot.This is generally known as the dead visual range of a ship. To address this, cameras are sometimes placed in

neg: The Blind Spot The Blind Spot The Blind Spot is a science fiction novel by American writers Austin Hall and Homer Eon Flint. The novel was originally serialized in six parts in the magazine "Argosy" beginning in May 1921. It was first published in book form in 1951 by Prime Press in an edition of 1,500 copies, though fewer than 800 were bound and the remainder are assumed lost. The sequel, "The Spot of Life", was written by Hall alone. The novel concerns an interdimensional doorway between worlds. In "In Search of Wonder", Damon Knight is critical of the novel's coherence, scientific accuracy

neg: Photoreceptor cell amacrine cells in the retina. The final result is differing populations of ganglion cells in the retina, a sub-population of which is also intrinsically photosensitive, using the photopigment melanopsin. A non-rod non-cone photoreceptor in the eyes of mice, which was shown to mediate circadian rhythms, was discovered in 1991 by Foster "et al." These neuronal cells, called intrinsically photosensitive retinal ganglion cells (ipRGC), are a small subset (≈1–3%) of the retinal ganglion cells located in the inner retina, that is, in front of the rods and cones located in the outer retina. These light sensitive neurons contain a photopigment, melanopsin,

neg: Retinal regeneration this treatment gives hope to people with dysfunctional vision and including degenerative eye diseases such as retinitis pigmentosa. The procedure involved injecting rod precursors which formed an 'anatomically distinct and appropriately polarized outer nuclear layer' - two weeks later a retina had formed with restored connections and sight, proving that it was possible to reconstruct the entire light-sensitive layer. Researchers at Moorfields Eye Hospital had already been using human embryonic stem cells to replace the pigmented lining of the retina in patients with Stargardt's disease. The team is also restoring vision to blind patients with an electronic retinal implant which

neg: Neurostimulation pathway usually includes a back telemetry voltage sampler that reads the voltage over a period of time on the recording electrode. The stimulator block is responsible to deliver predetermined current by external unit to the microelectrodes. This block includes a reference current and a digital to analog converter to transform digital commands to an analog current. Theoretical and experimental clinical evidences suggest that direct electrical stimulation of the retina might be able to provide some vision to subjects who have lost the photoreceptive elements of their retina. Therefore, visual prostheses are developed to restore vision for the blind by using

neg: The Blind Spot and style: Groff Conklin, however, more generously termed "The Blind Spot" an "honored classic" despite being "overwritten [and] leaning a little heavily on the pseudo-metaphysical." Forrest J Ackerman described it in "Astounding" as a "luxuriantly glorious Merrittesque [fantasy] of dimensional interstices" and "a highly philosophical work." Everett F. Bleiler wrote that "The Blind Spot" "used to be regarded as one of the classics of early science-fiction, but now it is much less esteemed." He concluded that while its opening section "evoke[s] a considerable sense of wonder," the novel "soon degenerates into a routine adventure story with loose ends." The Blind

neg: Retinal scan Retinal scan A retinal scan is a biometric technique that uses unique patterns on a person's retina blood vessels. It is not to be confused with another ocular-based technologies, iris recognition, commonly called an "iris scan", and eye vein verification that uses scleral veins." The human retina is a thin tissue composed of neural cells that is located in the posterior portion of the eye. Because of the complex structure of the capillaries that supply the retina with blood, each person's retina is unique. The network of blood vessels in the retina is not entirely genetically determined and thus even

neg: Progressive retinal atrophy fundus. The pigmented spots eventually coalesce and fade as the atrophy of the retina increases. It is an inherited condition (in the Labrador Retriever it is inherited as an autosomal dominant trait with variable penetrance). CPRA occurs in older dogs. Peripheral vision is retained for a long time. Vision is better in low light and better for moving or distant objects. Not all affected dogs go blind. Secondary cataracts are common. It can also be found in the poodle varieties There is another retinal disease in Briards known as hereditary retinal dysplasia. These dogs are night blind from birth, and

neg: Macular hole slowly shrinks on its own. Treatment is also done using ocriplasmin. Macular hole A macular hole is a small break in the macula, located in the center of the eye's light-sensitive tissue called the retina. If the vitreous is firmly attached to the retina when it pulls away, it can tear the retina and create a macular hole. Also, once the vitreous has pulled away from the surface of the retina, some of the fibers can remain on the retinal surface and can contract. This increases tension on the retina and can lead to a macular hole. In either case,

neg: Absolute threshold that 5 to 14 of the estimated 500 rods in the test area would each absorb one photon, with a 4% chance that one rod would absorb two photons. A second absolute threshold for vision involves the minimum photon flux (photons per second per unit area). In this case the light covers a wide field over an extended period of time instead of being concentrated on one spot on the retina in a short burst. Knowing the pupil diameter and the wavelength of the light, the result can be described in terms of luminance (~0.000001 candela per square meter or

neg: Filling-in similar phenomena, such as the filling-in of illusory contours or the filling-in through artificial scotomata or adapted edges (such as in the Troxler's effect). All these phenomena are indeed similar, and probably rely on similar neural circuitries but they are not identical. For instance, an obvious difference between filling-in across the blind spot and filling-in of occluded edges is that filling-in across the blind spot is modal (i.e. you literally see the filled-in section), while filling-in across occluders is amodal. Filling-in across the blind spot was found to be different also from filling-in across cortical scotomata in two patients examined

neg: Blind Spot (1958 film) can't pep up a tired script;" while the "Radio Times" rated the film two out of five stars, calling it a "stolid British crime yarn." "The Movie Scene" gave the film three out of five stars, noting, "Robert MacKenzie appeared to make only three movies yet going on what he does as Dan Adams in 'Blind Spot' makes me think he could have had a solid movie career...after a decent set up "Blind Spot" quickly unravels in to an ordinary 1950s crime drama with nothing to make it stand out except that it features a young Michael Caine." Blind Spot

neg: Macular degeneration of those 70 to 80, and nearly 12% of people over 80 years old. Signs and symptoms of macular degeneration include: Macular degeneration by itself will not lead to total blindness. For that matter, only a small number of people with visual impairment are totally blind. In almost all cases, some vision remains, mainly peripheral. Other complicating conditions may lead to such an acute condition (severe stroke or trauma, untreated glaucoma, etc.), but few macular degeneration patients experience total visual loss. The area of the macula comprises only about 2.1% of the retina, and the remaining 97.9% (the peripheral field)

neg: Central serous retinopathy Central serous retinopathy Central serous retinopathy (CSR), also known as central serous chorioretinopathy (CSC or CSCR), is an eye disease that causes visual impairment, often temporary, usually in one eye. When the disorder is active it is characterized by leakage of fluid under the retina that has a propensity to accumulate under the central macula. This results in blurred or distorted vision (metamorphopsia). A blurred or gray spot in the central visual field is common when the retina is detached. Reduced visual acuity may persist after the fluid has disappeared. The disease is considered of unknown cause. It mostly affects

neg: Albert Sandrin Jr. Albert Sandrin Jr. He won the 1949 U.S. Open in Omaha, and took 2nd in the 1951 U.S. Open in Fort Worth. He won the Illinois State Championship in 1944 and the Chicago Championship in 1946, 1949, 1957, and 1968. Sandrin had pigmentary degeneration of the retina. He was already almost completely blind at the time of the 1949 U.S. Open. After the founding of the International Braille Chess Association (IBCA) in 1958, he represented the U.S. in the World Blind Championships of 1970 and 1982, and played first board for the U.S. team in the Blind Olympiads of 1968,

neg: Macular hole Macular hole A macular hole is a small break in the macula, located in the center of the eye's light-sensitive tissue called the retina. If the vitreous is firmly attached to the retina when it pulls away, it can tear the retina and create a macular hole. Also, once the vitreous has pulled away from the surface of the retina, some of the fibers can remain on the retinal surface and can contract. This increases tension on the retina and can lead to a macular hole. In either case, the fluid that has replaced the shrunken vitreous can then seep

neg: Mark Pollock on to study Business and Economics in Trinity College, Dublin, where he became a champion schools rower and captain of the university's rowing club but aged 22 he lost the sight in his left eye and was then suddenly blind. In 2010, just weeks before his wedding, Pollock fell from an upstairs window, breaking his back and fracturing his skull. This caused bleeding on the brain and resulted in paralysis. Pollock has been blind since the age of twenty-two when his left retina became detached. This had a devastating effect on him as he believed at the time that blind

neg: Geordi La Forge "Star Trek Nemesis". "New Scientist" magazine reported on research as to whether a device similar to a VISOR can actually be created for blind or visually impaired people. Partial sight has been successfully restored to blind rats by installing an implant behind the retina. Several types of visual prosthesis are in development or trials in humans, and one device has been approved for sale in the European market. , 16 blind people worldwide have had sight partially restored in a procedure where electrodes implanted in their brains take impulses from a camera to allow patients to see lights and outlines

neg: Blind Spot (1958 film) Blind Spot (1958 film) Blind Spot is a 1958 British drama film directed by Peter Maxwell and starring Robert MacKenzie, Delphi Lawrence, Gordon Jackson, John Le Mesurier and Michael Caine in an early screen appearance. Laid up in a military hospital waiting for an operation, U.S. Army Captain Dan Adams (Robert MacKenzie), has lost his sight due to a head injury. While his doctors are waiting for his injury to heal before proceeding, Adams is driven off the base to a party but is dropped off at the wrong address. Entering the house, he stumbles over a body and startles

neg: Blind spot monitor the upcoming CX-3, often as part of an option package. Ford uses the acronym BLIS for its blind spot detection. The system is active both in "drive" and "neutral" transmission gears, and is turned off when in reverse or park gears. On Ford products, the system was first introduced in the spring of 2009, on the 2010 Ford Fusion and Fusion Hybrid, 2010 Mercury Milan and Milan Hybrid, and 2010 Lincoln MKZ. Mitsubishi offers a Blind Spot Warning (BSW) on the Pajero Sport launched in 2016. In 2010, the Nissan Fuga/Infiniti M for the first time offered countersteering capabilities to

neg: Blind Spot (Homeland) Blind Spot (Homeland) "Blind Spot" is the fifth episode of the first season of the psychological thriller TV series "Homeland". It originally aired on Showtime on October 30, 2011. The lone survivor of the al-Qaeda group that held Brody for eight years is captured. Saul and Carrie are to interrogate him, with Brody's help. Carrie (Claire Danes) visits her father, Frank (James Rebhorn), with the intent of pilfering some of his pills (he also has bipolar disorder). She manages to get some, but her visit is cut short when she gets a call telling her that the CIA has Afsal

neg: Stiles–Crawford effect an SCE-like drop in the intensity of light guided through the foveola. Tschukalow et al measured the transmission of collimated light under the light microscope at different angles after it had passed through human foveae from flat mounted isolated retinae. Light entering the fovea center, which is composed only of cones and Müller cells, at an angle of 0 degrees causes a very bright spot after passing through this area. However, when the angle of the light beam is changed to 10 degrees, less light is measured after transpasssing through the retina, the foveolar center becomes darker and the SCE-like

neg: Expert prevalent among novice learners. The blind spot metaphor refers to the physiological blind spot in human vision in which perceptions of surroundings and circumstances are strongly impacted by their expectations. Beginning practicing educators tend to overlook the importance of novice levels of prior knowledge and other factors involved in adjusting and adapting pedagogy for learner understanding. This expert blind spot is in part due to an assumption that novices’ cognitive schemata are less elaborate, interconnected, and accessible than experts’ and that their pedagogical reasoning skills are less well developed (Borko & Livingston, 1989: 474). Essential knowledge of subject matter for

neg: Retina one fovea, as opposed to certain bird species, such as hawks, who are bifoviate, and dogs and cats, who possess no fovea but a central band known as the visual streak. Around the fovea extends the central retina for about 6 mm and then the peripheral retina. The farthest edge of the retina is defined by the ora serrata. The distance from one ora to the other (or macula), the most sensitive area along the horizontal meridian is about 32 mm. In section, the retina is no more than 0.5 mm thick. It has three layers of nerve cells and

neg: Michael Kidner seen in their Pointillist paintings. Rothko's Colour Field abstractions led Kidner to see colour as "pure sensation". For example in his "Moving Green" 1959 the colours seem to float in an atmospheric colour relief in front of the canvas.On gazing at the colour field, the eye moves from the green to the red area and a bright, red spot or after image produced by the retina appears in the field. Later Kidner's After Image works became hard edged with flat uniform patterns, when he realised that optical activity producing shimmer is decreased by brushy paintwork and varied shapes. However After