The retina is the innermost layer of the eye that contains photoreceptor cells and ganglion cells. It has three distinct regions - the optic disc, macula lutea, and peripheral retina. The macula lutea contains the highest concentration of cones in the fovea and provides sharp central vision. The retina contains 10 layers including the retinal pigment epithelium, photoreceptor layers, bipolar cell layer, ganglion cell layer, and internal limiting membrane. The retina receives its blood supply from the central retinal artery and has no anastomoses. It contains two types of photoreceptor cells - rods for low light vision and cones for color and high acuity vision.
The retina develops from the optic cup during gestation. By 6 weeks, the retinal pigment epithelium and neurosensory retina have formed from the outer and inner layers of the optic cup. Between 4-12 weeks, the neurosensory retina differentiates into its layers. By birth, the retina has formed its layers - photoreceptor layer, plexiform layers, nuclear layers, ganglion cell layer and nerve fiber layer. The fovea develops later between 5-8 months. The retina has distinct topography with the optic disc, macula and peripheral regions having different thicknesses and cell densities to perform specialized functions like high acuity vision.
The retina is the light-sensitive tissue lining the back of the eye. It contains 10 layers including the retinal pigment epithelium, rods and cones, bipolar and ganglion cells. The retina is thinnest near the center and thickens toward the periphery. Key structures include the optic disc, macula with fovea for sharp central vision, and ora serrata marking the edge. The retina contains over 120 million light receptors and ganglion cells whose axons converge at the optic disc to form the optic nerve.
Tear film
1. TEAR FILM
2. The outer most layer of the cornea. It is the exposed part of the eyeball. FUNCTION It provide smooth optical surface It serves to keep the surface of cornea and conjunctiva moist. It serves as a lubricant for the preocular surface and lids It transfer oxygen from the air to the cornea Prevent infection due to the presence of antibacterial substance like lysozymes,and other protein. It wash away debris and irritants Provides pathway to WBC in case of injury.
3. LAYERS OF TEAR FILM It consist of three layers: 1.Lipid layer 2.Aqueous layer 3.Mucoid layer 1.LIPID LAYER
The cornea is the main refractive element of the eye, contributing 70% of the eye's refractive power. Even minor changes to its shape can significantly alter the image formed on the retina. The cornea has an elliptical anterior surface and a circular posterior surface. It varies in thickness from center to periphery. Corneal topography is used to map the shape of the cornea using various techniques such as Placido disk, elevation-based, and Scheimpflug imaging. Topography provides quantitative data on corneal curvature, thickness, and irregularities that aid in diagnosing conditions like keratoconus.
The retina is the innermost layer of the eye that converts light into neural signals. It contains several layers of tissue and cell types that carry out this visual transduction process. The outermost layer contains pigmented cells, followed by photoreceptor cells (rods and cones), bipolar and ganglion cells that transmit signals to the brain. Within the retina, the macula provides high-acuity central vision and the optic disc is where retinal ganglion cell axons exit as the optic nerve. The retina receives its blood supply from the central retinal artery and precise vascular architecture is important for normal visual function.
- A schematic eye is a mathematical model that represents the basic optical features of the real eye by using spherical surfaces and constant refractive indices.
- The first schematic eyes were developed in the 17th-19th centuries by scientists like Huygens, Smith, Le Grand, and Listing. Gullstrand further improved the model with four lens surfaces and refractive index gradients.
- Modern schematic eyes like Gullstrand's simplified model with three surfaces are commonly used for calculations involving refraction, image size and location, and the effects of refractive errors. While approximations, schematic eyes provide a framework for understanding ocular optics.
The retina develops from the optic cup during gestation. By 6 weeks, the retinal pigment epithelium and neurosensory retina have formed from the outer and inner layers of the optic cup. Between 4-12 weeks, the neurosensory retina differentiates into its layers. By birth, the retina has formed its layers - photoreceptor layer, plexiform layers, nuclear layers, ganglion cell layer and nerve fiber layer. The fovea develops later between 5-8 months. The retina has distinct topography with the optic disc, macula and peripheral regions having different thicknesses and cell densities to perform specialized functions like high acuity vision.
The retina is the light-sensitive tissue lining the back of the eye. It contains 10 layers including the retinal pigment epithelium, rods and cones, bipolar and ganglion cells. The retina is thinnest near the center and thickens toward the periphery. Key structures include the optic disc, macula with fovea for sharp central vision, and ora serrata marking the edge. The retina contains over 120 million light receptors and ganglion cells whose axons converge at the optic disc to form the optic nerve.
Tear film
1. TEAR FILM
2. The outer most layer of the cornea. It is the exposed part of the eyeball. FUNCTION It provide smooth optical surface It serves to keep the surface of cornea and conjunctiva moist. It serves as a lubricant for the preocular surface and lids It transfer oxygen from the air to the cornea Prevent infection due to the presence of antibacterial substance like lysozymes,and other protein. It wash away debris and irritants Provides pathway to WBC in case of injury.
3. LAYERS OF TEAR FILM It consist of three layers: 1.Lipid layer 2.Aqueous layer 3.Mucoid layer 1.LIPID LAYER
The cornea is the main refractive element of the eye, contributing 70% of the eye's refractive power. Even minor changes to its shape can significantly alter the image formed on the retina. The cornea has an elliptical anterior surface and a circular posterior surface. It varies in thickness from center to periphery. Corneal topography is used to map the shape of the cornea using various techniques such as Placido disk, elevation-based, and Scheimpflug imaging. Topography provides quantitative data on corneal curvature, thickness, and irregularities that aid in diagnosing conditions like keratoconus.
The retina is the innermost layer of the eye that converts light into neural signals. It contains several layers of tissue and cell types that carry out this visual transduction process. The outermost layer contains pigmented cells, followed by photoreceptor cells (rods and cones), bipolar and ganglion cells that transmit signals to the brain. Within the retina, the macula provides high-acuity central vision and the optic disc is where retinal ganglion cell axons exit as the optic nerve. The retina receives its blood supply from the central retinal artery and precise vascular architecture is important for normal visual function.
- A schematic eye is a mathematical model that represents the basic optical features of the real eye by using spherical surfaces and constant refractive indices.
- The first schematic eyes were developed in the 17th-19th centuries by scientists like Huygens, Smith, Le Grand, and Listing. Gullstrand further improved the model with four lens surfaces and refractive index gradients.
- Modern schematic eyes like Gullstrand's simplified model with three surfaces are commonly used for calculations involving refraction, image size and location, and the effects of refractive errors. While approximations, schematic eyes provide a framework for understanding ocular optics.
Specular microscopy is used to examine the corneal endothelium and analyze pathological changes. There are contact and non-contact types, with contact providing higher resolution but potential discomfort. The procedure involves placing the patient comfortably and using fixation to keep the eye still while obtaining images. Images are then analyzed to study normal endothelium morphology, diagnose corneal endothelial diseases, and monitor conditions like aging, diabetes, surgery, trauma, and compare surgical techniques. Specular microscopy can detect disorders like Fuchs' endothelial dystrophy and help with decisions like eye banking and surgery.
The Optics of Human Eye & Gallstrand schematic eyeHarsh Jain
The document summarizes key aspects of the human eye and optics. It describes how light stimulates vision and defines the electromagnetic spectrum. It then details the basic anatomy of the eye, including that it is divided into two chambers filled with aqueous and vitreous humor. Optics are discussed next, specifically how light enters through the cornea and pupil, is focused by the lens, and forms an image on the retina. Common refractive errors like myopia and hyperopia are also summarized. Finally, Gullstrand's schematic eye model is introduced as a simplified representation of the optical components and parameters of the typical human eye.
The document discusses the anatomy and surgical applications of the limbus. It defines the limbus as the transitional zone between the cornea and sclera, containing the pathways for aqueous humor outflow. Histologically, it describes how the layers of the cornea and conjunctiva become continuous at the limbus. Surgically, it notes the anterior limbal border, blue limbal zone, mid-limbal line, posterior limbal border, and white limbal zone. The best site for cataract incisions is the mid-limbal line, while anterior or posterior incisions risk damage to underlying structures. The limbus contains stem cells that renew the corneal epithelium.
This document provides an overview of the anatomy and development of the iris and some common congenital anomalies. It discusses the embryonic development of the iris from the optic cup and neural crest cells. The iris has 3 layers - an anterior limiting layer, iris stroma with muscles and blood vessels, and a posterior pigmented epithelial layer. The iris receives its arterial blood supply from the long and anterior ciliary arteries. It is innervated by both parasympathetic and sympathetic nerves that control the sphincter and dilator pupillae muscles. Common congenital anomalies discussed include heterochromia, aniridia, persistent pupillary membrane, and colobomata.
The uvea consists of the iris, ciliary body, and choroid. It develops from both neuroectoderm and vascular mesoderm. The iris develops fully by age 5, with pigmentation continuing after birth. The ciliary body appears by 9 weeks and is fully developed by 6 months gestation. The choroid layers are seen by 5 months gestation. The uvea regulates light entry and provides blood supply to the outer retina. Congenital anomalies include heterochromia, polycoria, persistent pupillary membranes, and colobomas. Uveitis is inflammation of the uveal tract.
The document provides an overview of the anatomy and physiology of the uveal tract. It describes the three parts of the uveal tract - iris, ciliary body, and choroid. The iris regulates the size of the pupil and gives eye color. The ciliary body secretes aqueous humor and helps with accommodation. It has ciliary processes that increase the surface area for secretion. Aqueous humor is formed through active transport of ions from the stroma into epithelial cells and through their gap junctions into the posterior chamber. The choroid provides nutrients and absorbs light.
The document summarizes the anatomy and physiology of the extraocular muscles (EOMs). It describes the 7 EOMs, their origins, insertions, actions, and nerve supply. The EOMs allow for precise eye movements through arrangements of fibers and innervation that provide both rapid and fatigue-resistant function. Their coordinated actions follow laws of ocular motility to produce conjugate and vergent eye movements in the cardinal gazes.
Bifocal lenses have two optical powers, one for distance vision and one for near vision. They are useful for presbyopia. There are several types of bifocal lenses including round, flat-top, and executive styles. Benjamin Franklin is credited with inventing the first bifocal lens in the late 18th century by cutting a single lens in half. Modern bifocals are manufactured using various techniques like fusing, cementing, or making from a single piece of plastic or glass. Proper positioning and design of the near segment is important to reduce issues like image jump and chromatic aberration. Bifocals come in many styles and materials to best suit individual needs and prescription requirements.
This document discusses various tests used to evaluate stereopsis and depth perception. It describes:
1. Tests of gross stereopsis like the pencil test that evaluate the ability to perceive depth with both eyes open versus monocularly.
2. The Frisby and Randot stereotests that use displaced shapes or dots seen through polarized lenses to test fine stereopsis.
3. Administration and passing criteria for the TNO and Lang stereotests which use random dot patterns to evaluate minimum stereoacuity.
4. The Fly test and Titmus test which similarly use vectographic images seen through polarized lenses but include shapes of increasing difficulty to measure fine stereoacuity.
The uvea consists of the iris, ciliary body, and choroid. It develops from both neuroectoderm and mesoderm. The iris controls the pupil size and appears by 9 weeks gestation. The ciliary body produces aqueous humor and appears by 9 weeks. The choroid supplies the outer retina and appears by 5 months gestation. The uvea contains muscles, epithelia, and vasculature. It is susceptible to inflammation and various congenital anomalies that can affect its structure and function.
This document provides an overview of the anatomy of the cornea including its dimensions, structures, physiology, and nerve supply. The cornea has 5 layers - epithelium, Bowman's layer, stroma, Descemet's membrane, and endothelium. It is avascular and transparent to allow for vision. The epithelium is stratified and squamous, the stroma contains collagen bundles, and the endothelium maintains deturgescence of the stroma. The cornea has important optical and protective functions for the eye.
The eyelids are composed of several layers including skin, muscle, orbital septum, fat and conjunctiva. The upper eyelid is raised by the levator palpebrae superioris muscle and Muller's muscle. The lower eyelid is retracted by the capsulopalpebral fascia. Several glands including the meibomian glands and glands of Zeis and Moll are located within the eyelids and help form the tear film. The orbicularis oculi muscle allows for eyelid closure and blinking. Together, the eyelid structures protect the eye and help spread tears across the surface of the eye.
Entoptic phenomena are visual effects and sensations that occur from causes within the human eye itself. Some key entoptic phenomena include floaters and flashes caused by vitreous changes, the Purkinje tree and blue field phenomenon caused by viewing retinal blood vessels, Haidinger's brushes and Maxwell's spot related to macular pigmentation, and blue arcs and phosphenes resulting from retinal or neural stimulation. These phenomena are caused by normal eye anatomy or may result from various pathological conditions. The observer cannot share a direct view of entoptic phenomena with others as they are caused by structures within one's own eye.
Detailed instumentaion and use of manual Lensometer and just a outline of automated lensometer.
I have used the picture of manual lensometer with out the parts describtion because i have explained orally by showing the picture..
Hope u all like it and may help you in learning better. :)
This document discusses the blood supply of the eye. It begins by outlining the main arteries involved - the ophthalmic artery, cerebral arteries, circle of Willis, and external carotid artery. It then provides detailed descriptions of each artery's origin, course, branches and clinical significance as they relate to supplying structures of the eye. This includes descriptions of the central retinal artery and its branches within the retina, as well as the conjunctival and episcleral arteries. It also briefly discusses the arteries of the brain including the internal and vertebral arteries, basilar artery, and circle of Willis.
This document provides an overview of the anatomy and microscopic structure of the retina. Key points include:
- The retina is a thin, delicate membrane lining the back of the eyeball. It contains photoreceptor cells (rods and cones) and neuronal layers.
- Gross anatomical regions include the optic disc, macula lutea, and peripheral retina. The macula contains the fovea centralis, which provides high-acuity central vision.
- Microscopically, the retina contains layers including the retinal pigment epithelium, photoreceptor outer and inner segments, plexiform layers, and ganglion cell layer.
- Rod and cone photoreceptors contain light-
The document summarizes the Amsler grid, a diagnostic tool used since 1945 to screen for and monitor macular diseases. It consists of a grid with a central dot that patients look at to detect any distortions, gaps, or blurred areas in their central vision. Various versions are available, including ones with different colors, patterns of lines, or dot sizes to test specific parts of the visual field and detect different types of visual abnormalities that could indicate conditions like macular degeneration or glaucoma. The procedure involves having patients view the grid with each eye separately at 16 inches and report any anomalies in the lines of the grid.
The ciliary body is part of the uvea and is located between the iris and choroid. It is composed of two parts - the ciliary processes and ciliary muscle. The ciliary processes project forward from the ciliary body and contain capillaries and pigmented and non-pigmented epithelial layers important for aqueous humor production. The ciliary muscle allows for accommodation by changing the shape and tension of the lens. The ciliary body receives its blood supply from the short and long posterior ciliary arteries and drains into the anterior ciliary veins and vena vorticosa. It plays key roles in aqueous humor production, maintenance of intraocular pressure, and accommodation.
The document discusses the anatomy and physiology of the retina. It begins by describing the embryological origin and topography of the retina. It then describes the major anatomical structures in detail, including the optic disc, macula lutea, fovea, and layers of the retina. The microscopic architecture contains 10 layers arranged from the sclerad to the vitread side. The physiology section briefly outlines the process of phototransduction and visual signal transmission through the retina and visual pathways.
Specular microscopy is used to examine the corneal endothelium and analyze pathological changes. There are contact and non-contact types, with contact providing higher resolution but potential discomfort. The procedure involves placing the patient comfortably and using fixation to keep the eye still while obtaining images. Images are then analyzed to study normal endothelium morphology, diagnose corneal endothelial diseases, and monitor conditions like aging, diabetes, surgery, trauma, and compare surgical techniques. Specular microscopy can detect disorders like Fuchs' endothelial dystrophy and help with decisions like eye banking and surgery.
The Optics of Human Eye & Gallstrand schematic eyeHarsh Jain
The document summarizes key aspects of the human eye and optics. It describes how light stimulates vision and defines the electromagnetic spectrum. It then details the basic anatomy of the eye, including that it is divided into two chambers filled with aqueous and vitreous humor. Optics are discussed next, specifically how light enters through the cornea and pupil, is focused by the lens, and forms an image on the retina. Common refractive errors like myopia and hyperopia are also summarized. Finally, Gullstrand's schematic eye model is introduced as a simplified representation of the optical components and parameters of the typical human eye.
The document discusses the anatomy and surgical applications of the limbus. It defines the limbus as the transitional zone between the cornea and sclera, containing the pathways for aqueous humor outflow. Histologically, it describes how the layers of the cornea and conjunctiva become continuous at the limbus. Surgically, it notes the anterior limbal border, blue limbal zone, mid-limbal line, posterior limbal border, and white limbal zone. The best site for cataract incisions is the mid-limbal line, while anterior or posterior incisions risk damage to underlying structures. The limbus contains stem cells that renew the corneal epithelium.
This document provides an overview of the anatomy and development of the iris and some common congenital anomalies. It discusses the embryonic development of the iris from the optic cup and neural crest cells. The iris has 3 layers - an anterior limiting layer, iris stroma with muscles and blood vessels, and a posterior pigmented epithelial layer. The iris receives its arterial blood supply from the long and anterior ciliary arteries. It is innervated by both parasympathetic and sympathetic nerves that control the sphincter and dilator pupillae muscles. Common congenital anomalies discussed include heterochromia, aniridia, persistent pupillary membrane, and colobomata.
The uvea consists of the iris, ciliary body, and choroid. It develops from both neuroectoderm and vascular mesoderm. The iris develops fully by age 5, with pigmentation continuing after birth. The ciliary body appears by 9 weeks and is fully developed by 6 months gestation. The choroid layers are seen by 5 months gestation. The uvea regulates light entry and provides blood supply to the outer retina. Congenital anomalies include heterochromia, polycoria, persistent pupillary membranes, and colobomas. Uveitis is inflammation of the uveal tract.
The document provides an overview of the anatomy and physiology of the uveal tract. It describes the three parts of the uveal tract - iris, ciliary body, and choroid. The iris regulates the size of the pupil and gives eye color. The ciliary body secretes aqueous humor and helps with accommodation. It has ciliary processes that increase the surface area for secretion. Aqueous humor is formed through active transport of ions from the stroma into epithelial cells and through their gap junctions into the posterior chamber. The choroid provides nutrients and absorbs light.
The document summarizes the anatomy and physiology of the extraocular muscles (EOMs). It describes the 7 EOMs, their origins, insertions, actions, and nerve supply. The EOMs allow for precise eye movements through arrangements of fibers and innervation that provide both rapid and fatigue-resistant function. Their coordinated actions follow laws of ocular motility to produce conjugate and vergent eye movements in the cardinal gazes.
Bifocal lenses have two optical powers, one for distance vision and one for near vision. They are useful for presbyopia. There are several types of bifocal lenses including round, flat-top, and executive styles. Benjamin Franklin is credited with inventing the first bifocal lens in the late 18th century by cutting a single lens in half. Modern bifocals are manufactured using various techniques like fusing, cementing, or making from a single piece of plastic or glass. Proper positioning and design of the near segment is important to reduce issues like image jump and chromatic aberration. Bifocals come in many styles and materials to best suit individual needs and prescription requirements.
This document discusses various tests used to evaluate stereopsis and depth perception. It describes:
1. Tests of gross stereopsis like the pencil test that evaluate the ability to perceive depth with both eyes open versus monocularly.
2. The Frisby and Randot stereotests that use displaced shapes or dots seen through polarized lenses to test fine stereopsis.
3. Administration and passing criteria for the TNO and Lang stereotests which use random dot patterns to evaluate minimum stereoacuity.
4. The Fly test and Titmus test which similarly use vectographic images seen through polarized lenses but include shapes of increasing difficulty to measure fine stereoacuity.
The uvea consists of the iris, ciliary body, and choroid. It develops from both neuroectoderm and mesoderm. The iris controls the pupil size and appears by 9 weeks gestation. The ciliary body produces aqueous humor and appears by 9 weeks. The choroid supplies the outer retina and appears by 5 months gestation. The uvea contains muscles, epithelia, and vasculature. It is susceptible to inflammation and various congenital anomalies that can affect its structure and function.
This document provides an overview of the anatomy of the cornea including its dimensions, structures, physiology, and nerve supply. The cornea has 5 layers - epithelium, Bowman's layer, stroma, Descemet's membrane, and endothelium. It is avascular and transparent to allow for vision. The epithelium is stratified and squamous, the stroma contains collagen bundles, and the endothelium maintains deturgescence of the stroma. The cornea has important optical and protective functions for the eye.
The eyelids are composed of several layers including skin, muscle, orbital septum, fat and conjunctiva. The upper eyelid is raised by the levator palpebrae superioris muscle and Muller's muscle. The lower eyelid is retracted by the capsulopalpebral fascia. Several glands including the meibomian glands and glands of Zeis and Moll are located within the eyelids and help form the tear film. The orbicularis oculi muscle allows for eyelid closure and blinking. Together, the eyelid structures protect the eye and help spread tears across the surface of the eye.
Entoptic phenomena are visual effects and sensations that occur from causes within the human eye itself. Some key entoptic phenomena include floaters and flashes caused by vitreous changes, the Purkinje tree and blue field phenomenon caused by viewing retinal blood vessels, Haidinger's brushes and Maxwell's spot related to macular pigmentation, and blue arcs and phosphenes resulting from retinal or neural stimulation. These phenomena are caused by normal eye anatomy or may result from various pathological conditions. The observer cannot share a direct view of entoptic phenomena with others as they are caused by structures within one's own eye.
Detailed instumentaion and use of manual Lensometer and just a outline of automated lensometer.
I have used the picture of manual lensometer with out the parts describtion because i have explained orally by showing the picture..
Hope u all like it and may help you in learning better. :)
This document discusses the blood supply of the eye. It begins by outlining the main arteries involved - the ophthalmic artery, cerebral arteries, circle of Willis, and external carotid artery. It then provides detailed descriptions of each artery's origin, course, branches and clinical significance as they relate to supplying structures of the eye. This includes descriptions of the central retinal artery and its branches within the retina, as well as the conjunctival and episcleral arteries. It also briefly discusses the arteries of the brain including the internal and vertebral arteries, basilar artery, and circle of Willis.
This document provides an overview of the anatomy and microscopic structure of the retina. Key points include:
- The retina is a thin, delicate membrane lining the back of the eyeball. It contains photoreceptor cells (rods and cones) and neuronal layers.
- Gross anatomical regions include the optic disc, macula lutea, and peripheral retina. The macula contains the fovea centralis, which provides high-acuity central vision.
- Microscopically, the retina contains layers including the retinal pigment epithelium, photoreceptor outer and inner segments, plexiform layers, and ganglion cell layer.
- Rod and cone photoreceptors contain light-
The document summarizes the Amsler grid, a diagnostic tool used since 1945 to screen for and monitor macular diseases. It consists of a grid with a central dot that patients look at to detect any distortions, gaps, or blurred areas in their central vision. Various versions are available, including ones with different colors, patterns of lines, or dot sizes to test specific parts of the visual field and detect different types of visual abnormalities that could indicate conditions like macular degeneration or glaucoma. The procedure involves having patients view the grid with each eye separately at 16 inches and report any anomalies in the lines of the grid.
The ciliary body is part of the uvea and is located between the iris and choroid. It is composed of two parts - the ciliary processes and ciliary muscle. The ciliary processes project forward from the ciliary body and contain capillaries and pigmented and non-pigmented epithelial layers important for aqueous humor production. The ciliary muscle allows for accommodation by changing the shape and tension of the lens. The ciliary body receives its blood supply from the short and long posterior ciliary arteries and drains into the anterior ciliary veins and vena vorticosa. It plays key roles in aqueous humor production, maintenance of intraocular pressure, and accommodation.
The document discusses the anatomy and physiology of the retina. It begins by describing the embryological origin and topography of the retina. It then describes the major anatomical structures in detail, including the optic disc, macula lutea, fovea, and layers of the retina. The microscopic architecture contains 10 layers arranged from the sclerad to the vitread side. The physiology section briefly outlines the process of phototransduction and visual signal transmission through the retina and visual pathways.
The document summarizes key aspects of retinal anatomy. It describes the layers of the retina including the retinal pigment epithelium, layers of rods and cones, internal limiting membrane and others. It also describes important structures like the optic disc, macula lutea, fovea and ora serrata. Cell types within the layers like photoreceptors, bipolar cells and ganglion cells are also defined.
The retina has several layers that serve important functions. The retinal pigment epithelium acts as a barrier and aids in visual pigment regeneration. The layers of rods and cones contain the light-sensitive photoreceptor cells that convert light signals into nerve impulses. Deeper retinal layers like the inner nuclear layer and ganglion cell layer contain neuron cell bodies that transmit these signals to the brain.
The retinal anatomy document summarizes the layers and structures of the retina. It notes that the retina consists of 10 distinct layers, including the retinal pigment epithelium, photoreceptor layer, and ganglion cell layer. It describes landmarks such as the macula lutea, fovea centralis, and optic disc. The document also discusses the blood supply to the retina from the central retinal artery and choroidal capillaries, as well as the neuroglial and neurotransmitter components of the retina.
The retina has multiple layers that process light and transmit visual signals. The outermost layer is the retinal pigment epithelium, followed inwardly by the layers of photoreceptors, bipolar and ganglion cells. The innermost layer is the nerve fiber layer containing ganglion cell axons. Specialized structures include the macula for high acuity vision and optic disc where ganglion cell axons exit as the optic nerve. Blood supply comes from the choroid circulated by the ciliary arteries. The retina converts light to electrical signals that travel through the optic nerve to the brain for visual processing.
The retina is the innermost layer of the eye that receives light signals and converts them into neural signals. It has 10 layers and can be divided into the posterior pole and peripheral retina. The posterior pole contains the optic disc and macula lutea, which contains the fovea centralis - the most light-sensitive region of the retina responsible for clear central vision. The retina receives its blood supply from the central retinal artery and veins and has both avascular and vascular regions.
The document summarizes the anatomy and physiology of the retina. It describes the three main regions of the retina - optic disc, macula lutea, and peripheral retina. It details the microscopic layers of the retina and the cells within each layer. It discusses the visual pigments rhodopsin and cone pigments, and how light induces photochemical changes in these pigments to initiate the visual process. Finally, it briefly outlines the pathway of visual signal transmission from the retina to the visual cortex.
The retina is a thin layer of tissue that lines the back of the eye on the inside. It is located near the optic nerve. The purpose of the retina is to receive light that the lens has focused, convert the light into neural signals, and send these signals on to the brain for visual recognition.
The retina is the innermost layer of the eye that receives and processes light. It contains specialized light-sensitive cells and is divided into 10 layers. The outermost layer contains melanin pigment to absorb light, while the inner layers contain photoreceptor cells, bipolar cells, ganglion cells and supporting Muller cells. The retina is thinnest at the fovea and thickest near the optic disc. It receives blood supply from the choroid and central retinal artery and vein. The retina contains the macula, optic disc and peripheral regions and can be affected by various congenital anomalies.
The retina is the innermost layer of the eyeball and consists of two main layers - the outer retinal pigment epithelium and the inner neurosensory layer. The retinal pigment epithelium is a single layer of hexagonal cells that absorbs light and supports the photoreceptor cells. The neurosensory layer contains the photoreceptor cells (rods and cones), bipolar cells, ganglion cells, horizontal cells, amacrine cells, and Muller cells arranged into 10 distinct layers. The retina receives its blood supply from both the choroidal capillaries and the central retinal artery and vein.
The retina is the innermost layer of the eye that contains photoreceptive cells and converts light into neural signals. It has 10 layers including the retinal pigment epithelium, layers of photoreceptors and neurons, and the internal limiting membrane. The retina contains rod and cone photoreceptors, bipolar and ganglion neurons, and receives dual blood supply from the choroid and central retinal vessels. It has a macula lutea region containing the fovea centralis for high acuity vision.
1. The retina is the innermost layer of the eyeball and contains photoreceptor cells that convert light into neural signals. It develops from the inner and outer layers of the optic cup.
2. The retina contains three main regions - the optic disc, macula lutea, and peripheral retina. The macula contains the fovea centralis which has the highest concentration of cone photoreceptors and allows for high acuity vision.
3. The retina has 10 layers including the retinal pigment epithelium, layers of photoreceptor cells, and ganglion cell layer. The retinal pigment epithelium supports the function of the photoreceptors and forms the blood-retinal barrier.
Retina : an overview
Seminar Presentation include Anatomy, Physiology, Pathology, Medical management and surgical management of retinal diseases and also latest updates. The Seminar was written and posted by famous ophthalmologist--
Dr Niraj Kumar Yadav
MBBS, MS Ophthalmology
FICM, FID, NDEP Liverpool UK
Anatomy of Retina by Robin Singh ( BMCO )Robin Singh
The retina is the innermost layer of the eye that receives light and converts it into nerve impulses. It has three distinct regions - the optic disc, macula lutea, and peripheral retina. The retina contains 10 layers including the retinal pigmented epithelium, rods and cones, plexiform layers, and ganglion cell layer. It receives its blood supply from both the central retinal artery and choriocapillaris. The macula lutea contains the fovea which is the most light-sensitive region of the retina.
The retina is a thin, multilayered sheet of neural tissue that lines the back interior of the eye. It contains several important structures including the optic disc, retinal blood vessels, and the area centralis containing the fovea and foveola. Microscopically, the retina consists of 10 layers including the retinal pigment epithelium, layers of photoreceptor cells, and ganglion cell layer. The retina converts light signals to neural signals which are transmitted to the brain via the optic nerve. It receives its blood supply from both the choroid and central retinal artery.
The retina is a thin, light-sensitive tissue that lines the back of the eye. It contains 10 layers including photoreceptors that convert light into neural signals. The macula contains the highest concentration of cones and allows for sharp, central vision. The optic disc is where retinal blood vessels and optic nerve fibers exit the eye. The retina receives dual blood supply from the central retinal artery and choroidal vessels. It contains over 120 million light-sensitive rods and cones and transmits visual information through the optic nerve to the brain.
The retina is a thin, multilayered neural tissue that lines the back of the eyeball. It contains specialized cells for vision like rods and cones. The vitreous humor is a clear jelly-like substance that fills the back portion of the eyeball. It helps maintain the shape of the eye and provides a pathway for nutrients. The vitreous is comprised of collagen fibrils suspended in hyaluronic acid. It can be divided into the vitreous cortex attached to surrounding structures, and the vitreous nucleus in the center. The retina and vitreous have an important anatomical relationship and work together for clear vision.
The uvea consists of the iris, ciliary body, and choroid.
The iris regulates the size of the pupil and is composed of two muscle layers - the sphincter pupillae and dilator pupillae. The ciliary body contains the ciliary muscle which helps with accommodation and produces aqueous humor in the ciliary processes. The choroid is the highly vascular layer that nourishes the outer retina.
Similar to ANATOMY OF RETINA - DR.RUTHRA.pptx (20)
5-hydroxytryptamine or 5-HT or Serotonin is a neurotransmitter that serves a range of roles in the human body. It is sometimes referred to as the happy chemical since it promotes overall well-being and happiness.
It is mostly found in the brain, intestines, and blood platelets.
5-HT is utilised to transport messages between nerve cells, is known to be involved in smooth muscle contraction, and adds to overall well-being and pleasure, among other benefits. 5-HT regulates the body's sleep-wake cycles and internal clock by acting as a precursor to melatonin.
It is hypothesised to regulate hunger, emotions, motor, cognitive, and autonomic processes.
These lecture slides, by Dr Sidra Arshad, offer a simplified look into the mechanisms involved in the regulation of respiration:
Learning objectives:
1. Describe the organisation of respiratory center
2. Describe the nervous control of inspiration and respiratory rhythm
3. Describe the functions of the dorsal and respiratory groups of neurons
4. Describe the influences of the Pneumotaxic and Apneustic centers
5. Explain the role of Hering-Breur inflation reflex in regulation of inspiration
6. Explain the role of central chemoreceptors in regulation of respiration
7. Explain the role of peripheral chemoreceptors in regulation of respiration
8. Explain the regulation of respiration during exercise
9. Integrate the respiratory regulatory mechanisms
10. Describe the Cheyne-Stokes breathing
Study Resources:
1. Chapter 42, Guyton and Hall Textbook of Medical Physiology, 14th edition
2. Chapter 36, Ganong’s Review of Medical Physiology, 26th edition
3. Chapter 13, Human Physiology by Lauralee Sherwood, 9th edition
10 Benefits an EPCR Software should Bring to EMS Organizations Traumasoft LLC
The benefits of an ePCR solution should extend to the whole EMS organization, not just certain groups of people or certain departments. It should provide more than just a form for entering and a database for storing information. It should also include a workflow of how information is communicated, used and stored across the entire organization.
Histololgy of Female Reproductive System.pptxAyeshaZaid1
Dive into an in-depth exploration of the histological structure of female reproductive system with this comprehensive lecture. Presented by Dr. Ayesha Irfan, Assistant Professor of Anatomy, this presentation covers the Gross anatomy and functional histology of the female reproductive organs. Ideal for students, educators, and anyone interested in medical science, this lecture provides clear explanations, detailed diagrams, and valuable insights into female reproductive system. Enhance your knowledge and understanding of this essential aspect of human biology.
2. • The Retina is the
innermost tunic of the
eyeball which is a thin,
delicate and transparent
membrane and is the most
highly developed tissue of
the eyeball.
3. GROSS ANAT. OF RETINA
• Extent : From the optic disc to the
ora serrata
• Surface area : 266 mm2
• Thickness : At posterior pole 0.56mm
At the ora serrata 0.1mm
• Colour : Purplish red
(visual rhodopsin)
• Regions : 3 distinct regions
Optic disc
Macula Lutea
Peripheral retina(General fundus)
TO ADD PICTURE
4. OPTIC DISC
• 1.5 mm diameter, well defined circular
area
• Appears pale (pale pink) due to lamina
cribrosa and absence of vasculature
• Physiological Cup: Depression seen in
it , central retinal vessels emerge
through the Centre of this cup.
• At the optic disc- All retinal layers
terminate except nerve fibres , which
pass through the lamina cribrosa to run
into optic nerve.
5. MACULA LUTEA (Area Centralis)
• About 5.5mm, temporal to theoptic disc
betweenthetemporal vascular arcades.
• Yellowcolour due to presence of the
oxygenated carotenoid (Zeaxanthine and
Lutein) pigment.
• Approx. 15 degree visual field, Photopic and
colour vision primarily
• Macular regiondivisible into
FOVEOLA
FOVEA
PARA FOVEOLAR ZONE
PERI FOVEOLAR ZONE
6. FOVEA
• Concave central retinal depression at Posterior pole
of globe.
• Diameter-1. 5mm –5 degrees of visual field
• Cones only
FOVEOLA
• central floor of the fovea where INNER NUCLEAR
and GANGLION LAYER are absent
• 0.35mm in diameter and 0.15mm in thickness
UMBO ( LIGHT REFLEX)
• Tiny depression seen in the Centre of foveola viz
referred to as the central bouquet of cones (150 to
200 micrometer) due to greatest concentration of
cones.
7. FOVEAL AVASCULAR ZONE
• Is located inside the fovea but outside the foveola.
• 0.3TO 0.6 mm
• Important in FA to identify Fovea Centre
PARAFOVEA
• Refers to a belt that measures 0.5mm in width which
surrounds the margin of fovea.
• This include 4-6 layers of ganglion cell and 7-10 layers of
bipolar cells.
PERIFOVEA
• Refers to a belt which measures 1.5mm in width and
surrounds the parafoveal area.
• This include several layers of ganglion cells and Six layers of
bipolar cells.
8. PERIPHERAL RETINA
• Increases the field of vision
• Divided into 4 regions
NEAR PERIPHERY-1.5mm around area centralis
MID PERIPHERY- 3mm wide zone around near
periphery till equator
FAR PERIPHERY- from optic disc- 9-10 mm on
temporal side and 16 mm on nasal side , from
equator till ora serrata
EXTREME PERIPHERY -Ora serrata and pars plana
10. RETINAL PIGMENT EPITHELIUM
• Outermost layer of the retina.
• Consists of single layer of hexagonal
shaped cells containing pigment
• It is thickly adherent to the underlying
Bruch's membrane and loosely to the
layer of rods and cones of the retina.
• The space between RPE and the sensory
retina is called subretinal space.
• Separation of the RPE from sensory
retina is called retinal detachment and
the fluid between the two layers is called
Sub retinal fluid (SRF).
11. • RPE cells are connected to each other by tight
junctions i.e. zonulae occludents and zonulae
adherents. Forming the outer blood retinal barrier.
• Apical part – containing microvilli towards rods and
cones along with MELANIN and LIPOFUSCIN pigments
• Basal part – towards Bruch's membrane containing
infoldings to increase surface area
• FUNCTIONS
Recycling of vitamin A.
Maintains the integrity of sub retinal space.
Transport of nutrients and metabolites.
Phagocytosis of photoreceptors.
Manufactures pigment.
Regeneration and repairing after injury.
12. LAYER OF RODS AND CONES (Neuro epithelium)
• Rods and cones (photo receptors) , end organs of vision , transform
light energy into nerve impulses.
• Rods contain photosensitive substance Rhodopsin whereas cones
contain Idopsin
• Cone cells – Photopic and central vision , Rod cells - Scotopic vision and
peripheral
• Cones = 6.5M , Rods = 120M
• At fovea maximum cones are present and rods are absent.
14. STRUCTURE OF ROD CELL
• Length = 40-60µm
• Outer segment is cylindrical , contains Rhodopsin & composed
of numerous protein lamellar disc.(600-1000/rod)
• Disc contain 90°/o of visual purple.
• Outer segment is attached to inner via cilium.
• Inner segment is thicker and has regions as
Outer - Ellipsoid ( mitochondria)
Inner - Myoid (organelles)
• Outer rod fibres- from inner segment at EXTERNAL.L.M,
swells into nucleus (rod granule) at the OUTER.NUC.L
and ends as Inner rod fibre as rod spherule at OUT.PLEX.L
15. STRUCTURE OF CONE CELL
•Length = 40-8Oµm
•Outer segment is conical viz shorter than
rod.
•Contains Iodopsin pigment packed in
lamellar disc.(1000-1200 disc/cone)
•Inner segment & cilium are similar to rods.,
But contain many mitochondria and end as
lateral processes called CONE FOOT at
OUTER.PLEX.L
16. EXTERNAL LIMITING MEMBRANE
• Fenestrated membrane extending from the ora serrata up to
the edge of optic disc. ( then as basal lamina between
pigmented and non pigmented epithelium of ciliary body)
• Processes of rods and cones pass through it.
• This layer is formed by the junction between the cell
membrane of photoreceptors & muller cells.( not a true
basement membrane)
18. OUTER NUCLEAR LAYER
• Made up of the nuclei of rods & cones.
• Cones nuclei - 6-7µm , Rod nuclei -
5.5µm , nuclei lie in a single layer next
to the E.L.M.
• Rod nuclei form the bulk of this layer
except at the cone dominated foveal
region. ( 10 layers)
• Stain with Mallory stain
Cones- red , rods – orange
19. OUTER PLEXIFORM LAYER
• Synapses between rod spherules
and cone pedicles with dendrites of
bipolar cells and processes of
horizontal cells
• Marks the junction of end organs of
vision and 1st order neurons in
retina.
• Thickest at macula 51 µm consists of
predominantly of oblique fibres that
have deviated from fovea also
known as HENLE’S LAYER.
21. • Contribute to vertical
communication
within the retinal
layer.
• Carry out
paracrine
functions.
• As principal glial cells, act as a
supportive framework and a
nutritive function.
• Astrocytes (mc around vessels),
oligo
And microglia
• Synapses with the
processes of Amacrine
cells and cell bodies of
the diffuse ganglion
cells.
• Neuronal interconnections
between photoreceptors
and bipolar cells .
• A cells with Cones
• B cells with Rods
Horizont
al
cells
Bipola
r
cells
Amacrin
e
cells
Müller
cells
Neurons of First Order
22. BIPOLARCELLS
Type Connections Peculiarity
1. Rod
Bipolar
Cells
20%,
Large
soma
profuse
dendrites
Arborize only with rod
spherules
Axons of these bipolar
cells have synapses
with soma up to 4
ganglion cells
2.
Midget
Bipolar
cells
Small
Make connections only in
triads of cone pedicle
Invaginating-
Deeply
invaginate cone
pedicle
Flat- Makes superficial
contact with cone
pedicle
Axons synapses with
SINGLE
ganglion cell.
3. Diffuse- Makes contact with cone
pedicles only
Not with their triads
Axons synapse with
number of
ganglion cells of all types.
4. Blue cone
bipolar cells
Innervate more than one cone
pedicle
23. INNER PLEXIFORM LAYER
• Synapses between Axons of bipolar cells
(1st order neurons) and Ganglion cells ( 2nd
order neurons)
• Amacrine cells also mediate
interactions within the layer and the
interplexiform cells receive input
from the Amacrine cells
• Also contains processes of Muller
cells , abundant microvasculature
, occasional displaced nucleus of
a ganglion / Amacrine cells.
• Layer is absent at foveola
24. GANGLION CELL LAYER
• Mainly composed of cell bodies 2nd order neurons of visual pathway
• Others: Processes of Müller cells, other neuroglia, branches of retinal
vessels are also present.
• At foveola and optic nerve head, ganglion cell layer is absent.
• Near foveola 6-8 layers, temporal side of optic disc 2 layers and at periphery
single layer
• TYPES W,X,Y ganglion
Off center & on center cell
MONOSYNAPTIC (central) & POLYSYNAPTIC CELL (peripheral retina)
1.2 million ganglion
cells at retina
Each produce a
single axon
Converge and exit
from the eye as
OPTIC NERVE
Synapse with cells of LGB , 3rd order neurons
25. NERVE FIBRE LAYER (stratus opticum)
• Formedbythe axons of the ganglion cells
• Theydonot become myelinateduntiltheypass through the lamina
cribrosa
• The myelinsheath beingformedbythe oligodendrocytes
• Also has centrifugal fibres, muller cells processes, retinal vessels and neuro
glial cells – macro ( structure) and microglia (wandering histiocytes)
ARRANGEMENT OF NERVE FIBRE IN RETINA
1. Nasal Half: Directly to optic disc as superior and inferior radiating
fibres (Srf & Irf).
2. Macular region: Pass straight in temporal part of disc as
papillomacular bundle.(PMB)
3. Temporal retina: Arch above and below the macular/ as superior /
inferior arcuate fibres. (Saf & Iaf).
26. INTERNAL LIMITING MEMBRANE
• Pas positive true basement membrane.
• Forms interface between retina and vitreous.
• Consists of elements:
Processes of Müller cells and other glial cells
Collagen fibrils
Proteoglycans
Basement membrane
27. BLOOD SUPPLY
• Outer four layers – Choriocapillaris
• Inner six layers- Central retina Artery
• Retina is supplied by Central RetinalArtery, Enters optic nerve on lower
surface 15-20 mm behind the globe.
• At the optic disc divide as sup and inf branches – nasal and temporal
• Retinal arteries are end arteries and have no anastomosis at ora
serrata.
• Fovea is avascular but partially gets blood supply from choriocapillaris.
• Macular area gets blood supply from central retinal artery .
28. • Superficial capillary network lies at the nerve fibre layer
• Deep network lies between inner nuclear and outer
plexiform layer – more dense
• BLOOD RETINAL BARRIER
• The endothelial cells of retinal capillaries are closely bound
together (zona occludens type) and form Blood Retinal
Barrier – absence of fluorescence leakage
• The endothelial cells lined by basement membrane around
which there are pericytes. Pericytes also have basement
membrane
• Ratio of endo : pericytes is 1:1