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| Human eye as an optical presentation system. Presentation - the eye as an optical system. I performed tasks ... |
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"I sing in front of you in rapture praise not to expensive stones, not gold, but glass" M.V. Lomonosov   Answers F \u003d 0.1m; D \u003d 10 diopters F \u003d 0.2m; D \u003d 5 diopters F \u003d 0.25 m; D \u003d 4 diopters F \u003d -0.15 m; D \u003d - 6.7dptr Score-4 points  Solving problems 1.There are two lenses: converging with focal length F 1 \u003d 50 cm and scattering with optical power D 2 \u003d -8.5 diopters. What is the optical power of this lens system ? 2.What is the optical power of the system of two lenses, if the focal length of one lens is F 1 \u003d 40 cm, and the optical power of the other is D 2 \u003d 6dptr?  Solving problems 3.What is the optical power of the system of two lenses, if the focal length of one lens is F 1 \u003d 5 cm, and the optical power of another D 2 \u003d -3 diopters. 4. Optical power of one of the lenses D 1 \u003d -25 diopters. Other focal length - F 2 \u003d 100 mm. What is the optical power of the system of these lenses?  Answers: 1. D \u003d -6.5 diopters. 2. D \u003d -3.5 diopters. 3. D \u003d 17 diopters 4.D \u003d -15 diopters. Score-4 points  Lesson topic : The eye is like an optical system. Visual defects and ways to correct them. Optical devices.   Mini-project No. 1 The eye is the organ of vision. Defects of vision and ways to eliminate them.   Visual defects Myopia Farsightedness    Mini-project number 2 The principle of the camera. Pinhole camera  1- lens 2-film 3-shutter Camera    Mini-project number 3 How the telescope works . reflectors refractors  Thin lens formula 1 / F \u003d 1 / d 0 + 1 / di Telescope magnification M \u003d M1 * M2 \u003d \u003d (- di1 / d 0 1) / (- di2 / d 0 2) M \u003d (- 29.2 / 63.4) / (- 102.2 / 9.6) \u003d -4.9  Mini-project No. 4 How the microscope works .  Thin lens formula 1 / F \u003d 1 / d0 + 1 / di Microscope magnification M \u003d M1 * M2 \u003d \u003d (- di1 / d 01 ) / (- di2 / d 02 ) M \u003d (- 19.2 / 20.9) / (-54.9 / 14.8) \u003d - 3.41   Homework : 1. Determine the optical power of the eyeglass lenses available in your home. 2. Determine which lens is installed in the door peephole. Find out what will be the image of the object obtained with its help.  Reflective screen today I found out ... it was interesting… it was difficult… i performed tasks ... i realized that ... now I can… i felt that ... i bought ... i learned… i managed … i could ... i'll try… surprised me ... gave me a lesson for life ... i wanted…  Lesson summary "5" - 15 points "4" - 14 points "3" - 13 points 
Completed: Student orgma 123 gr. treat.fak. Kochetova Christina Slide 2 A person perceives objects of the external world by analyzing the image of each of the objects on the retina. The retina is the light-receiving department. The images of objects around us on the retina are rendered using the optical system of the eye. The optical system of the eye consists of: Cornea Lens Vitreous humor Slide 3 The cornea, the cornea (lat.cornea) is the anterior most convex transparent part of the eyeball, one of the light-refracting media of the eye. The cornea in humans occupies about 1/16 of the area of \u200b\u200bthe outer shell of the eye. It looks like a convex-concave lens, with its concave part facing backwards, it is transparent, due to which light passes into the eye and reaches the retina. Normally, the cornea is characterized by the following features: sphericity specularity transparency high sensitivity absence of blood vessels. Functions: protective and supporting functions (provided by its strength, sensitivity and ability to quickly recover) light conduction and light refraction (provided by the transparency and sphericity of the cornea). Slide 4 Six layers are distinguished in the cornea: the anterior epithelium, the anterior borderline membrane (Bowman's), the main corneal substance, or the stroma Dua layer, the posterior borderline membrane (Descemet's sheath), the posterior epithelium, or the corneal endothelium. Slide 5 The lens (lens, lat.) Is a transparent biological lens, which has a biconvex shape and is included in the light-conducting and light-refracting systems of the eye, and provides accommodation (the ability to focus on objects at different distances). There are 5 main functions of the lens: Light conduction: The transparency of the lens ensures the transmission of light to the retina. Refraction: As a biological lens, the lens is the second (after the cornea) refractive medium of the eye (at rest, the refractive power is about 19 diopters). Accommodation: The ability to change its shape allows the lens to change its refractive power (from 19 to 33 diopters), which provides focusing of vision on various distant objects. Dividing: Due to the peculiarities of the location of the lens, it divides the eye into an anterior and posterior section, acting as an "anatomical barrier" of the eye, keeping the structures from moving (prevents the vitreous from moving into the anterior chamber of the eye). Protective function: the presence of the lens makes it difficult for microorganisms to penetrate from the anterior chamber of the eye into the vitreous body during inflammatory processes. Slide 6 The human eye as an optical systemThe structure of the lens. The lens is similar in shape to a biconvex lens, with a flatter front surface. The lens diameter is about 10 mm. The main substance of the lens is enclosed in a thin capsule, under the anterior part of which there is an epithelium (there is no epithelium on the posterior capsule). The lens is located behind the pupil, behind the iris. It is fixed with the help of the finest threads ("zinn ligament"), which are woven into the lens capsule at one end, and connected to the ciliary (ciliary body) and its processes at the other. It is due to the change in the tension of these threads that the shape of the lens and its refractive power change, as a result of which the process of accommodation takes place. Innervation and blood supply The lens has no blood and lymphatic vessels, nerves. Metabolic processes are carried out through the intraocular fluid, which surrounds the lens on all sides. Slide 7 The human eye as an optical system.The vitreous body is a transparent gel that fills the entire cavity of the eyeball, the area behind the lens. Functions of the vitreous body: conducting light rays to the retina due to the transparency of the medium; maintaining the level of intraocular pressure; ensuring the normal location of intraocular structures, including the retina and lens; compensation for intraocular pressure drops due to sudden movements or injuries due to the gel-like component. Slide 8 The structure of the vitreous body The volume of the vitreous body is only 3.5-4.0 ml, while 99.7% of it is water, which helps to maintain a constant volume of the eyeball. The vitreous body in front is adjacent to the lens, forming a small depression in this place, on the sides it borders on the ciliary body, and along its entire length - on the retina. Slide 9 The rays of light that are reflected from the objects under consideration necessarily pass through 4 refractive surfaces: the back and front surfaces of the cornea, the back and front surfaces of the lens. Slide 10 Construction of the image on the retina.Each of these surfaces deflects the light beam from its original direction, which is why a real, but inverted and reduced image of the observed object appears in the focus of the optical system of the organ of vision. Slide 11 Johannes Kepler (1571 - 1630) was the first to prove that the image on the retina is inverted by constructing the path of rays in the optical system of the eye. To test this conclusion, the French scientist René Descartes (1596 - 1650) took the eye of a bull and, scraping off an opaque layer from its back wall, placed it in a hole made in a window shutter. And right there, on the semi-transparent wall of the fundus, he saw an inverted image of the picture observed from the window. Slide 12 Why, then, do we see all objects as they are, i.e. not inverted? The fact is that the process of vision is continuously corrected by the brain, which receives information not only through the eyes, but also through other senses. In 1896 the American psychologist J. Stretton performed an experiment on himself. He put on special glasses, thanks to which the images of surrounding objects on the retina turned out not to be reversed, but straight. He began to see all objects upside down. Because of this, there was a mismatch in the work of the eyes with other senses. The scientist developed symptoms of seasickness. For three days, he felt nauseous. However, on the fourth day the body began to return to normal, and on the fifth day Stretton began to feel the same as before the experiment. The scientist's brain got used to the new working conditions, and he again began to see all objects straight. But when he took off his glasses, everything turned upside down again. Within an hour and a half, his vision was restored, and he began to see normally again. Slide 13 The refraction of light in the eye's optical system is called refraction. The theory of refraction is based on the laws of optics, which characterize the propagation of light rays in a variety of media. The straight line that passes through the centers of all refractive surfaces is the optical axis of the eye. Light rays falling parallel to this axis are refracted and collected in the main focus of the system. These rays emanate from infinitely distant objects, therefore the main focus of the optical system is the place on the optical axis, where the image of infinitely distant objects appears. Diverging beams, which come from those objects that are located at a finite distance, are already collected in additional foci. They are located farther than the main focus, because additional refractive power is required to focus the diverging rays. The more the incident rays diverge (the proximity of the lens to the source of these rays), the greater the refractive power is required. Slide 14 Slide 15 Disadvantages of the optical system of the eye and the physical basis for their elimination.Thanks to accommodation, the image of the objects in question is obtained just on the retina of the eye. This is done if the eye is normal. The eye is called normal if it collects parallel rays in a relaxed state at a point lying on the retina. The two most common eye defects are myopia and hyperopia. Slide 16 A short-sighted eye is one in which the focus, when the eye muscle is calm, lies inside the eye. Myopia can be caused by the greater distance of the retina from the lens compared to the normal eye. If the object is located at a distance of 25 cm from the myopic eye, then the image of the object will be obtained not on the retina, but closer to the lens, in front of the retina. To get the image on the retina, you need to bring the object closer to the eye. Therefore, in the myopic eye, the best vision distance is less than 25 cm. Slide 17 In order for the image to move to the retina, it is necessary to reduce the optical power of the refractive system of the eye. For this, a diffusing lens is used. To correct myopia, glasses with concave, diffusing lenses are used. Slide 18 Farsighted is an eye in which the focus, when the eye muscle is at rest, lies behind the retina. Farsightedness can be caused by the retina being closer to the lens than the normal eye. The image of an object is obtained behind the retina of such an eye. If the object is removed from the eye, then the image will fall on the retina, hence the name of this defect - farsightedness. Slide 19 The optical power of the system of the farsighted eye must be increased in order for the image to fall on the retina. For this, a collecting lens is used. Glasses for farsighted eyes use convex, collecting lenses. Slide 1
The presentation on the topic "Human eye as an optical system" can be downloaded absolutely free of charge on our website. Project subject: Physics. Colorful slides and illustrations will help you engage your classmates or audience. To view the content, use the player, or if you want to download the report - click on the corresponding text under the player. The presentation contains 20 slide (s). Presentation slides
Slide 1 The human eye as an optical system. Construction of the image on the retina. Disadvantages of the optical system of the eye and the physical basis for their elimination. Completed: Student orgma 123 gr. treat.fak. Kochetova Christina
Slide 2 The human eye as an optical system. A person perceives objects of the external world by analyzing the image of each of the objects on the retina. The retina is the light-receiving department. The images of the objects around us on the retina are rendered with the help of the optical system of the eye. The optical system of the eye consists of: Cornea Lens Vitreous humor
Slide 3 The cornea, the cornea (lat.cornea) is the anterior most convex transparent part of the eyeball, one of the light-refracting media of the eye. The cornea in humans occupies about 1/16 of the area of \u200b\u200bthe outer shell of the eye. It looks like a convex-concave lens, with its concave part facing backwards, it is transparent, due to which light passes into the eye and reaches the retina. Normally, the cornea is characterized by the following features: sphericity specularity transparency high sensitivity absence of blood vessels. Functions: protective and supporting functions (provided by its strength, sensitivity and ability to quickly recover) light conduction and light refraction (provided by the transparency and sphericity of the cornea).
Slide 4
Slide 5 The lens (lens, lat.) Is a transparent biological lens, which has a biconvex shape and is included in the light-conducting and light-refracting system of the eye, and provides accommodation (the ability to focus on objects at different distances). There are 5 main functions of the lens: Light conduction: The transparency of the lens ensures the transmission of light to the retina. Refraction: As a biological lens, the lens is the second (after the cornea) refractive medium of the eye (at rest, the refractive power is about 19 diopters). Accommodation: The ability to change its shape allows the lens to change its refractive power (from 19 to 33 diopters), which provides focusing of vision on various distant objects. Dividing: Due to the peculiarities of the location of the lens, it divides the eye into an anterior and posterior section, acting as an "anatomical barrier" of the eye, keeping the structures from moving (prevents the vitreous from moving into the anterior chamber of the eye). Protective function: the presence of the lens makes it difficult for microorganisms to penetrate from the anterior chamber of the eye into the vitreous body during inflammatory processes.
Slide 6 The human eye as an optical system The structure of the lens. The lens is similar in shape to a biconvex lens, with a flatter front surface. The lens diameter is about 10 mm. The main substance of the lens is enclosed in a thin capsule, under the anterior part of which there is an epithelium (there is no epithelium on the posterior capsule). The lens is located behind the pupil, behind the iris. It is fixed with the help of the finest threads ("zinn ligament"), which are woven into the lens capsule at one end, and connected to the ciliary (ciliary body) and its processes at the other. It is due to the change in the tension of these threads that the shape of the lens and its refractive power change, as a result of which the process of accommodation takes place. Innervation and blood supply The lens has no blood and lymphatic vessels, nerves. Metabolic processes are carried out through the intraocular fluid, which surrounds the lens on all sides.
Slide 7 The vitreous body is a transparent gel that fills the entire cavity of the eyeball, the area behind the lens. Functions of the vitreous body: conducting light rays to the retina due to the transparency of the medium; maintaining the level of intraocular pressure; ensuring the normal location of intraocular structures, including the retina and lens; compensation for intraocular pressure drops due to sudden movements or injuries due to the gel-like component.
Slide 8 The structure of the vitreous body The volume of the vitreous body is only 3.5-4.0 ml, while 99.7% of it is water, which helps to maintain a constant volume of the eyeball. The vitreous body is adjacent to the lens in front, forming a small depression in this place, on the sides it borders on the ciliary body, and along its entire length - on the retina.
Slide 9
Slide 10 Construction of the image on the retina. Each of these surfaces deflects the light beam from its original direction, which is why a real, but inverted and reduced image of the observed object appears in the focus of the optical system of the organ of vision.
Slide 11 Johannes Kepler (1571 - 1630) was the first to prove that the image on the retina is inverted by constructing the path of rays in the optical system of the eye. To test this conclusion, the French scientist René Descartes (1596-1650) took the eye of a bull and, scraping off an opaque layer from its back wall, placed it in a hole made in a window shutter. And right there, on the semi-transparent wall of the fundus, he saw an inverted image of the picture observed from the window.
Slide 12 Why then do we see all objects as they are, i.e. not inverted? The fact is that the process of vision is continuously corrected by the brain, which receives information not only through the eyes, but also through other senses. In 1896 the American psychologist J. Stretton performed an experiment on himself. He put on special glasses, thanks to which the images of surrounding objects on the retina turned out not to be reversed, but straight. He began to see all objects upside down. Because of this, there was a mismatch in the work of the eyes with other senses. The scientist developed symptoms of seasickness. For three days, he felt nauseous. However, on the fourth day, the body began to return to normal, and on the fifth day Stretton began to feel the same way as before the experiment. The scientist's brain got used to the new working conditions, and he again began to see all objects straight. But when he took off his glasses, everything turned upside down again. Within an hour and a half, his vision was restored, and he began to see normally again.
Slide 13 Refraction of light in the eye's optical system is called refraction. The theory of refraction is based on the laws of optics, which characterize the propagation of light rays in a variety of media. The straight line that passes through the centers of all refractive surfaces is the optical axis of the eye. Light rays, incident parallel to this axis, are refracted and collected in the main focus of the system. These rays emanate from infinitely distant objects, so the main focus of the optical system is the place on the optical axis where the image of infinitely distant objects appears. Diverging beams, which come from those objects that are located at a finite distance, are already collected in additional foci. They are located farther than the main focus, because additional refractive power is required to focus the diverging rays. The more the incident rays diverge (the proximity of the lens to the source of these rays), the more refractive power is required.
Slide 15 Disadvantages of the optical system of the eye and the physical basis for their elimination. Thanks to accommodation, the image of the objects in question is obtained just on the retina of the eye. This is done if the eye is normal. The eye is called normal if it collects parallel rays in a relaxed state at a point lying on the retina. The two most common eye defects are myopia and hyperopia.
Slide 16 A short-sighted eye is one in which the focus, when the eye muscle is calm, lies inside the eye. Myopia can be caused by the greater distance of the retina from the lens compared to the normal eye. If the object is located at a distance of 25 cm from the myopic eye, then the image of the object will be obtained not on the retina, but closer to the lens, in front of the retina. To get the image on the retina, you need to bring the object closer to the eye. Therefore, in the myopic eye, the best vision distance is less than 25 cm. Image in the eye: Now consider the eye as an optical system. It includes the cornea, lens, vitreous body. The main role in the creation of the image belongs to the lens. It focuses the rays on the retina, resulting in an actual reduced inverted image of objects, which the brain corrects in a straight line. The rays are focused on the retina, at the back of the eye.
Eye defects. We know that there are some visual defects, they can be congenital or acquired due to improper lifestyle. But both congenital and acquired vision defects in question can be eliminated in whole or in part, subject to regular training and following the doctor's recommendations. Of the eye defects in humans, the most common eye defects are myopia (myopia), hyperopia (hypermetropia), astigmatism and strabismus.
Nearsightedness (myopia). Nearsightedness or myopia is an eye disease in which a person sees close objects well and poorly sees distant objects. This occurs as a result of excessive refractive power of the cornea and lens of the eye, or because of the elongation of the eyeball (due to which the rays coming from distant objects are focused not on the retina, but in front of it). In medicine, several degrees of myopia are distinguished: Weak myopia, moderate and severe myopia, pathological myopia, pseudomyopia.
Treatment of myopia This is a long process. All methods of treating myopia are aimed at stopping or slowing down the development of myopia, as well as preventing the development of various complications that can be caused by myopia. When treating myopia, glasses are used that act as a "crutch", that is, they seem to replace the functions of the eye itself. Correction of vision with glasses is carried out against the background of the use of eye drops, which dilate the pupil. Such drops are used to relax the eyes and relieve the spasm of accommodation. Along with these measures, various exercises can be prescribed to strengthen and relax the eye muscles, exercises with changing lenses.
Farsightedness (hyperopia) Farsightedness, hyperopia is a deviation from the normal refraction of the eye, which consists in the fact that parallel rays of light, after refracting them in the eye, are collected in a focus located, as it were, behind the retina of the eye. At the same time, the images on the retina are unclear, blurry.
Hyperopia treatment. Treatment of hyperopia is a long-term process, but observing the regime of lighting, visual and physical exertion, eating well and doing gymnastics for the eyes can prevent or improve vision with existing hyperopia Treatment of hyperopia (hyperopia) includes the selection of "plus" glasses, contact lenses or laser correction.
Astigmatism Astigmatism is a pathology of refraction of the eye in which the sphericity of the cornea is disturbed, i.e. in different meridians, different refractive power and the image of an object when light rays pass through such a cornea are obtained not in the form of a point, but in the form of a straight line segment. At the same time, a person sees objects distorted, in which some lines are clear, others are blurred.
Treating Astigmatism As with any disease, astigmatism must be treated early and early diagnosis is required. For the correction of astigmatism: glasses, contact lenses and surgery. Glasses help correct astigmatism in childhood. With a high degree of astigmatism, glasses are poorly tolerated: eyes begin to ache and dizzy. Glasses and contact lenses do not cure astigmatism, but only correct vision. You can get rid of astigmatism only with the help of surgery. There are several types of them: 1. Keratomy (to correct myopic or mixed astigmatism); 2. thermokeratocoagulation (for the correction of hyperopic astigmatism); 3. laser coagulation.
Strabismus treatment. There are various therapeutic and surgical treatments for strabismus. 1. Pleoptic treatment is an increased visual load on the squinting eye. At the same time, various methods of stimulating the worse seeing eye with a therapeutic laser, medical computer programs are used. 2. Orthopedic treatment is a treatment using synoptic devices and computer programs that restore the binocular activity of both eyes. 3. Diploptic treatment restoration of binocular and stereoscopic vision in vivo. 4. Training on a convergent trainer is a technique that improves the work of the internal rectus oculomotor muscles (reduction to the nose - convergence).
Slide 1The eye as an optical system. Slide 2
AT. Slide 3
We obtain most of the information about the world around us through vision. The human organ of vision is the eye - one of the most advanced and at the same time simple optical instruments. Slide 4
Eye structure Slide 5
The human eye has a spherical shape. The diameter of the eyeball is about 2.5 cm. Outside, the eye is covered with a dense opaque shell - the sclera. The front of the sclera merges into the transparent cornea, the cornea, which acts as a collecting lens and provides 75% of the eye's ability to refract light. Slide 6
The optical system of the eye can be viewed as a collecting lens. The lens plays the main role here. Slide 7
Correction of myopia is carried out by choosing diffusing lenses Slide 8
Simplified optical system of the eye Slide 9
Accommodation is the eye's ability to adapt to clearly distinguish objects located at different distances from the eye. Accommodation occurs by changing the curvature of the lens surfaces by stretching or relaxing the ciliary body. When the ciliary body is stretched, the lens is stretched and its radii of curvature increase. With a decrease in muscle tension, the lens increases its curvature under the influence of elastic forces. Slide 10
Myopia - this condition is often called myopia. It occurs when parallel beams of light entering the eye are focused in front of the retina. To obtain a clear image, a concave corrective lens must be placed in front of the cornea. Slide 11
Hypermetropia Slide 12
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