please help me describe how light passes through the eye. &&also what structures must light pass through before it reaches your retina?
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The structure of the mammalian eye owes itself completely to the task of focusing light onto the retina. All of the individual components through which light travels within the eye before reaching the retina are transparent, minimising dimming of the light. The cornea and lens help to converge light rays to focus onto the retina. This light causes chemical changes in the photosensitive cells of the retina, the products of which trigger nerve impulses which travel to the brain.\n\nLight enters the eye from an external medium such as air or water, passes through the cornea, and into the first of two humours, the aqueous humour. Most of the light refraction occurs at the cornea which has a fixed curvature. The first humour is a clear mass which connects the cornea with the lens of the eye, helps maintain the convex shape of the cornea (necessary to the convergence of light at the lens) and provides the corneal endothelium with nutrients. The iris, between the lens and the first humour, is a coloured ring of muscle fibres. Light must first pass though the centre of the iris, the pupil. The size of the pupil is actively adjusted by the circular and radial muscles to maintain a relatively constant level of light entering the eye. Too much light being let in could damage the retina; too little light makes sight difficult. The lens, behind the iris, is a convex, springy disk which focuses light, through the second humour, onto the retina.\n\nTo clearly see an object far away, the circularly arranged ciliary muscles will pull on the lens, flattening it. Without muscles pulling on it, the lens will spring back into a thicker, more convex, form. Humans gradually lose this flexibility with age, resulting in the inability to focus on nearby objects, which is known as presbyopia. There are other refraction errors arising from the shape of the cornea and lens, and from the length of the eyeball. These include myopia, hyperopia, and astigmatism.\n\nOn the other side of the lens is the second humour, the vitreous humour, which is bounded on all sides: by the lens, ciliary body, suspensory ligaments and by the retina. It lets light through without refraction, helps maintain the shape of the eye and suspends the delicate lens.\n\nThree layers, or tunics, form the wall of the eyeball. The outermost is the sclera which gives the eye most of its white colour. It consists of dense connective tissue filled with the protein collagen to both protect the inner components of the eye and maintain its shape. On the inner side of the sclera is the choroid, which contains blood vessels that supply the retinal cells with necessary oxygen and remove the waste products of respiration. Within the eye, only the sclera and ciliary muscles contain blood vessels. The choroid gives the inner eye a dark colour, which prevents disruptive reflections within the eye. The inner most layer of the eye is the retina, containing the photosensitive rod and cone cells, and neurons.\n\nTo maximise vision and light absorption, the retina is a relatively smooth (but curved) layer. It does have two points at which it is different; the fovea and optic disc. The fovea is a dip in the retina directly opposite the lens, which is densely packed with cone cells. It is largely responsible for colour vision in humans, and enables high acuity, such as is necessary in reading. The optic disc, sometimes referred to as the anatomical blind spot, is a point on the retina where the optic nerve pierces the retina to connect to the nerve cells on its inside. No photosensitive cells exist at this point, it is thus "blind".\n\nIn some animals, the retina contains a reflective layer (the tapetum lucidum) which increases the amount of light each photosensitive cell perceives, allowing the animal to see better under low light conditions.
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because it passes thru our cornea and hits our retina
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I assume that the light enters water through the glass since incidence is less than refracted angle also assuming refrative index of glass as 1.66 and water as 1.33\n\nWhat is the question then ? Also how can light return to where it originates ? That is dependent on the setup.
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Actually, the reason for this is known.  There are two major types of light-sensing cells in your retina, called rods and cones.  Cones are specialized for color vision and detail-they are concentrated in the central portion of your vision, so that when you look directly at something which isnt moving, you can see it very clearly, in color and detail.  The rods are black and white, and are specialized for low-light detection of movement.  Since the cones are in the center of your vision, there are more rods in the periphery of your vision.  If you think about it, this makes perfect evolutionary sense, since you want to quickly detect things moving in your periphery, so you can react to an attack-because humans have such excellent detail vision, we can detect things in our center of vision even when they arent moving (many carnivores, such as dogs, hve a difficult time seeing stationary objects), so we dont need such good "movement" vision in the center.  This arrangement also explains why color disappeas in low light, because cones require bright light, while rods work in dim light.  In addition, this explains why, in a dark room, you can actually see better in your peripheral vision-because the concentration of cones in the center of your retina is pretty useless in low light.
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Reflection of flashlight in the retina.\n\nFurther details:
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natural light is made up of different wavelength. differents wavelengths hit the grating at slightly different time. light doesnt pass through diffraction grating but its reflected from the grating to a photomultiplier because the gratings job is to divide the light in as many wavelengths as posible.
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1) its optical centre\n2) 1/2 cm\n3)converges, diverges\n4)perpendicular incidence of light\n5)ciliary muscles
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Just imagine that a ray of light bounces in a droplet of water, and that broken wavelength bounces out another side of the water droplet, divided into it's color components.\n\nThe only colored light that reaches your eye, is the water droplets that are uniquely pointing in your direction. Hence, the bow affect, since those droplets are uniquely pointing that color to your eyes. \n\nFunny way of thinking about it, but another person standing 1/2 mile away from you is seeing different water droplets producing the same rainbow affect. Even someone standing 10 feet way is seeing the affect of different water droplets.
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a translucent material reflects some of the light that hits it\n\nWhen light strikes a translucent material, it enters the body of the object, scatters and re-emerges from the surface\n\nIf an object is translucent, it will allow some of the light to come through, but most of the light is scattered
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ok, well think about what the resolving power means, first.  \n\nit says that if you take 2 point-like objects, and bring them closer and closer together, then your eye (or some optical instrument) will have a lower limit in terms of seeing them as 2 individual objects.  at some distance apart from one another, they will simply blur together and look like a single object or blobby thing.\n\nnow obviously, if the 2 objects are closer to your eye, then you can see them better, so the "distance between objects" is maybe not a very good way of determining your resolving power, because it depends on where the objects are.\n\na distance-independent way of stating the resolving power is in terms of the ANGLE between the objects.  this is the angle formed by the line that goes from object 1 to your eye, and the line that goes from object 2 to your eye.  for any given eye, there is some angular separation between 2 objects below which distinct objects cannot be resolved.  this angle is called the resolving power.  (radians are just a unit of angle, like degrees.  there are 2 * pi = 6.28 radians all the way around a circle.) \n\nso, if you think about it, someone with sharper vision can resolve 2 point-like objects that are closer together than can someone with poor vision.  this corresponds to a *smaller* angle because they're closer together.  so a small value for resolving power corresponds to sharp eyesight.\n\nas for optical or visual acuity, that is simply the reciprocal of the resolving power.  that means that a *larger* value means sharper eyesight.  in a medical context, visual acuity is usually expressed as something like 20/10 (which equals 2) for very good eyesight or 20/100 (which equals 0.2) for poor eyesight.  as you can see, the larger the value, the better the eyesight.\n\nhope this helps!\n\nps - have a look at this website if you need more info:\nhttp://www.tedmontgomery.com/the_eye/acuity.html
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I've never experienced a phenomenon that could not be related to some outside perturbation\n\nAs for the human retina, it has about 125 million rod photoreceptor cells (plus about 6 million cone cells, used mostly at night).  On a surface roughly 1/4th of that of a full format digital SLR today, the retina has about 10x more "pixels", i.e. a density 40x higher (and our own "pixels" don't interfere w eachother, unlike those of cameras ;-)\n\nGiven that from even as low as 10 megapixels is is pretty much impossible to see any on a postcard size print, I'd be very surprised if anyone could identify individual megapixels in the case of our own 125 megapixel camera ;-)\n\nhope this helps\n\na
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The retina in the back of the eye is a thin and transparent sensitive film.\n\nIt contains two types of receptor cells, rods and cones.\n\nCones handle day and color vision.\n\nRods are responsible for night vision. They are concentrated more at the sides of\nthe eye’s back wall. Therefore, objects are best seen at the sides, or ‘corners’ of our eyes, where rods are there.\n\nRods  are super sensitive than cones.  That is they respond to very small power of light.\n\nBut they take some 30 to 40 minutes to reach their maximum effectiveness.\n\nThey do not react to colors but react to the brightness.
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Question 1\n\nThe answer is A)  opaque and appears blue\n\nWe see the reflected blue light and all others colors are absorbed and therefore do not reach the eye. The object is opaque because none of the light can pass through the object.\n\nQuestion 2 can be tricky\n\nIf ALL of the blue light is transmitted and ALL of the other wavelengths are absorbed then you would have the following:\n\nIf you look through the object at a source the object will appear transparent and blue in color.\n\nIf you look at the object from the side that it is illuminated against a dark background, and if none of the light is reflected (either all absorbed or transmitted) the object will appear opaque and black.  However if some of the light is reflected, as would almost certainly be the case, then the object would likely appear blue and opaque.\n\nBasically, I can make the object in case 2 appear differently based on how I illuminate and view the object.  \n\nMy best answer for  (2) is (d) none of these, but probably not for the reason that the person posing the question had in mind.
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This is different than what is normally called the "blind spot".  That is a spot off to the side of your vision where all of the optic nerve enters the eyeball.  A good demonstration of the blind spot can be found in the link below.  You can even cut & paste the demo into paint and change the color of the spot to see how color affects it.\n\nWhat you're experiencing is a more subtle phenomenon.  Cones (think ice cream cone) sense color, while rods (think magician's rod) sense only black and white.  Rods are don't work well in bright light, but work very well in low light situations such as when all the lights are turned off, but there is still light from an outside street lamp.  OTOH, cones work well in bright light, but stop working almost completely in low light.  \n\nAnother aspect of this is that cones only cover central vision, whereas rods cover the entire retina.  There are also fewer rods in the central vision.\n\nSo.  You are in a dark room or on a dark street.  The light from the computer screen/car ahead of you knock out the rods in your central vision but not the peripheral vision.  Then the light goes out and the cones stop working while the central rods haven't gotten started yet, but the peripheral vision is still working well.  So you can see things out of the corner of your eye but it disappears when you look straight at it.  Boo!  It must be a ghost!
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You are on the right track. It's quite simple:\n\nGenerally, wet things look darker because they refract less light. Light, which is made of photons, refracts against an object and lands on your retina and your brain can register some amount of darkness or brightness. Now when that object is wet (assuming it is hydrophilic or "wettable") more light is absorbed by the water so less light lands in your eyes and the object appears darker.\n\nGreat question!
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The light was not reflected.  Think about this:  if you look into someone's eye (through their pupil), can you see the back of their eye?  No.  The light is actually absorbed by special cells in the retina called photoreceptors (rods and cones).  These cells start the transmission of light information to the brain.
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I dont know much but i would like to help you....u can use lenses...and a liquid similar to the vitreous humor.\nBut its really interesting that u r trying to create a Working model of human eye. Good luck.