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Ocular Anatomy PowerPoint Presentation

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Description : Check out this medical PowerPoint presentation titled "Ocular Anatomy” by Dr.Ajai Agrawal.

This medical PowerPoint presentation is about the eye, a complex organ that allows us to perceive the world around us. It consists of several different parts, each with its own unique function. Here are some of the main components of ocular anatomy:

Cornea: This is the clear, dome-shaped front surface of the eye that helps to focus incoming light.
Iris: The iris is the colored part of the eye that controls the size of the pupil, which regulates the amount of light that enters the eye.
Pupil: The pupil is the black circular opening in the center of the iris that allows light to enter the eye.
Lens: The lens is a clear structure located behind the iris that helps to focus light onto the retina.
Retina: The retina is a thin layer of tissue that lines the back of the eye and contains photoreceptor cells that convert light into electrical signals that can be sent to the brain.
Optic Nerve: The optic nerve is a bundle of nerve fibers that carries visual information from the retina to the brain.
Sclera: The sclera is the white, outer layer of the eye that helps to protect the eye and maintain its shape.
Choroid: The choroid is a layer of blood vessels located between the sclera and the retina that helps to nourish the retina.
Aqueous Humor: The aqueous humor is a clear, watery fluid that fills the front chamber of the eye and helps to maintain its shape.
Vitreous Humor: The vitreous humor is a gel-like substance that fills the back chamber of the eye and helps to maintain its shape.

These are just a few of the many parts of the eye that work together to enable us to see the world around us.

Tags : Ocular Anatomy, Cornea, Iris, Pupil, Retina, Optic Nerve, Sclera, Choroid, Aqueous Humor, Vitreous Humor, Ophthalmology, Ophthalmology PowerPoint presentation

Published on : Jun 20, 2023 | Views : 2039 | Downloads : 1

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Slide 1-

Ocular Anatomy Dr.Ajai Agrawal Additional Professor Department of Ophthalmology A.I.I.M.S., Rishikesh
Slide 2-

Acknowledgement Photographs included in the presentation are courtesy of Dr.Jonathan.J.Dutton and Dr.Thomas.G.Waldrop (Atlas of Clinical and Surgical Orbital Anatomy)
Slide 3-

Learning Objectives At the end of this class students shall be able to Identify various structures of the eye Have a basic understanding of the structure and functions of various parts of the eye
Slide 4-

Orbit Lodges the eyeball Eye lids – Cover and protect Lacrimal system- Secretes and drain tears Extraocular muscles- for ocular movements Layers of eyeball- perform various functions
Slide 5-

Bony Orbit Made by 7 Bones:- Frontal Zygomatic Maxillary Ethmoidal Sphenoid Lacrimal Palatine
Slide 6-

Frontal view of bony orbit
Slide 7-

Outer eye: Eyelids The eyelids fulfill two main functions: protection of the eyeball secretion, distribution and drainage of tears
Slide 8-

The eyelid muscles
Slide 9-

Lid structure and movement ● The levator muscle extends from an attachment at the orbital apex to attachments at the tarsal plate and skin. ● The lids are securely attached at either end to the bony orbital margin by medial and lateral palpebral ligaments.
Slide 10-

Innervation - Sensory innervation is from the trigeminal (fifth) cranial nerve, via the ophthalmic division (upper lid) and maxillary division (lower lid). - The orbicularis oculi is innervated by the facial (seventh) nerve. - The levator muscle in the upper lid is supplied by the oculomotor (third) nerve.
Slide 11-

Blood supply Network of blood vessels which form an anastomosis between branches derived from the external carotid artery via the face and from the internal carotid artery via the orbit.
Slide 12-

Lymphatics Lymphatic fluid drains into the preauricular and submandibular nodes. Preauricular lymphadenopathy is a useful sign of infective eyelid swelling (especially viral).
Slide 13-

Lacrimal system Lacrimal gland Lacrimal passage Lacrimal puncta Lacrimal canaliculi Lacrimal sac Naso-lacrimal duct
Slide 14-

Tear production The lacrimal gland secretes most of the aqueous component of the tear film Location: superotemporal part of the anterior orbit Innervation : parasympathetic fibres carried by the facial nerve.
Slide 15-

Lacrimal Apparatus/Drainage system
Slide 16-

Extraocular muscles 4 Recti 2 Obliques Medial rectus (MR) Inferior Rectus (IR) Superior rectus (SR) Inferior oblique (IO) Superior Oblique(SO) Lateral Rectus (LR)
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Extra-ocular muscles Action results in eye movements Medial Rectus --- Adduction Inferior Rectus --- Depression,Extorsion,Adduction Superior Rectus --- Elevation , Intorsion, Adduction Inferior Oblique--- Extorsion, Elevation, Abduction Superior Oblique--- Intorsion, Depression,Abduction Lateral Rectus --- Abduction
Slide 20-

EXTRAOCULAR MUSCLES
Slide 21-

Nerve supply of Extra Ocular Muscles Three Cranial Nerves supply the Extra Ocular Muscles CN 3rd-Oculomotor-MR, IR, SR, IO CN 4th-Trochlear—SO CN 6th- Abducens--- LR
Slide 22-

Overview of ocular anatomy
Slide 23-

Conjunctiva The conjunctiva is a mucous membrane lining the eyelids. Covers the anterior eyeball up to the edge of the cornea. At the upper and lower reflections between eyeball and eyelid, conjunctiva forms two sacs, the superior and inferior fornices .
Slide 24-

Cornea and sclera The cornea and sclera form a spherical shell which makes up outer wall of eyeball.
Slide 25-

Cornea and sclera The sclera is : - principally collagenous, - avascular (apart from some vessels on its surface) - relatively acellular. It is perforated posteriorly by the optic nerve, and by sensory and motor nerves and blood vessels to the eyeball. The cornea and sclera merge at the corneal edge (the limbus).
Slide 26-

Limbus Juncture between the cornea and the sclera Nourishes peripheral cornea Assists in corneal wound healing Pathway for aqueous outflow (contains trabecular meshwork and canal of schlemm)
Slide 27-

Corneoscleral limbus Transition zone: anterior：bowman`s terminal-Descemet’s terminal posterior：scleral spur／iris root 1.5～2.0mm width Appearance Semitransparant zone White sclera Angle of AC
Slide 28-

The chief functions of the cornea Protection against invasion of microorganisms into the eye Transmission and focusing (refraction) of light.
Slide 29-

Cornea Made up of 5 layers Specialized Transparent Tissue No blood vessels Primarily responsible for refracting light (43-44 diopters) More nerve endings than anywhere else in the body Protection to the eye The only part of the eye that is transplanted from one person to another
Slide 30-

Cornea Epithelium Bowman membrane Stroma Descemet membrane (posterior limiting layer of cornea) Endothelium
Slide 31-

Cornea- 5 layered
Slide 32-

Cornea Oval transverse：11.5～12mm vertical：10.5～11mm curvature：anterior： 7.8mm posterior：6.8mm thickness：centre：0.5～0.55mm periphery:1mm Refractive index：1.377
Slide 33-

1.Epithelium ： 50μm 5～6 layers Squamous cell Basal cell Renewing cycle≈7 days Cornea 2.Bowman’s membrane : 12 μm No cell Collagen ，matrix Scar
Slide 34-

3.Stroma 500 μm 2～3％ corneal cells 1％matrix（GAGs) Fibrous lamina 200～250 layers Parallel to surface Parallel collagen fibers Ordered arrangement Scar Cornea 4. Descemet’s membrane 10～12 μm No structure elasticity Secreted by endothelial cells Basal membrane of endothelial cell Regeneration
Slide 35-

5.Endothelium ： 5 μm Monolayer hexagon 500 000 cells Tight junctions Pump Cornea
Slide 36-

The uvea comprises the iris and ciliary body anteriorly choroid posteriorly UVEA
Slide 37-

Iris Consists of connective tissue containing muscle fibres, blood vessels and pigment cells. Its posterior surface is lined by a layer of pigment cells. At its centre is an aperture, the pupil. The main function of pupil: Control light entry to the retina and to reduce intraocular light scatter.
Slide 38-

Ciliary body The ciliary body is a specialised structure uniting the iris with the choroid. Secretes aqueous humour Anchors the lens via the zonules, through which it modulates lens convexity. The posterior part of the ciliary body merges into the retina at the ora serrata.
Slide 39-

Choroid The choroid, consisting of blood vessels, connective tissue and pigment cells, is sandwiched between the retina and the sclera. It provides oxygen and nutrition to the outer retinal layers.
Slide 40-

Lens The discus-like lens comprises a mass of long cells known as fibres. Has a hard nucleus surrounded by less dense fibres, the cortex. Relatively dehydrated Transparent.
Slide 41-

Aqueous humour Fills the anterior and posterior chambers. The anterior chamber is the space between the cornea and the iris. Behind the iris and in front of the lens is the posterior chamber. They are connected by the pupil.
Slide 42-

Formation The ciliary body forms aqueous humour By ultrafiltration and active secretion.
Slide 43-

Drainage Aqueous circulates from the posterior to the anterior chamber through the pupil. Passes through the trabecular meshwork (a specialised tissue in the anterior chamber angle between the iris and the cornea). From here aqueous drains into Schlemm's canal.
Slide 44-

Vitreous A thick, transparent gel like substance that fills the center of eyeball, giving it form and shape The vitreous body is 99% water but, vitally, also contains collagen fibrils and hyaluronan, which impart cohesion and a gel-like consistency. The vitreous is adherent to the retina at certain points, particularly at the optic disc and at the ora serrata. Volume - 4.5ml RI:1.3360≈aqueous humor
Slide 45-

Retina Innermost layer of the eye. Converts light energyelectrical energy --->brain via the optic nerve Composed of 10 layers. Contains Photoreceptors Cones-near Center (seeing detail and color) Rods- in Periphery (seeing in low light and movement)
Slide 46-

Transparent ,thin Anterior rim：ora serrata 3 parts:- Peripheral Retina Macula／fovea Optic disc Retina
Slide 47-

Optic disc Only optic nerve fibers Physiological blind spot Macula Thinnest Point of sharpest vision is in the fovea located in the center of the macula Retina
Slide 48-

Histology of retina 1 RPE 2 Layers of Rods & Cones 3 External Limiting Membrane 4 Outer Nuclear layer 5 Outer Plexiform layer 6 Inner Nuclear layer 7 Inner Plexiform Layer 8 Ganglion Cell layer 9 Nerve Fibre layer 10 Internal limiting membrane
Slide 49-

Retina The blood supply of the retina is derived from the central retinal artery and vein, and from the choroid. The retinal vessels enter and leave the eye through the optic nerve and run in the nerve fibre layer. A major arterial and venous branch, forming an 'arcade', supplies each of the retinal quadrants .
Slide 50-

Optic nerve The ganglion cell axons in the retinal nerve fibre layer make a right- angled turn into the optic nerve at the optic disc, which has no photoreceptors and corresponds to the physiological blind spot. Behind the eyeball these axons become myelinated. Here the optic nerve is surrounded by cerebrospinal fluid in an anterior extension of the subarachnoid space and is protected by the same membranous layers as the brain.
Slide 51-

Optic Nerve Pathways/Visual Cortex Message is carried down the optic nerve through pathways to occipital cortex; here vision becomes sight At the optic chiasm, the nasal nerve fibers cross; temporal nerve fibers go straight back to cortex; this arrangement impacts on visual fields Results in visual field losses can be predicted based on where damage is located on the optic nerve
Slide 52-

Conclusion The human eye is lodged inside bony orbit and protected by eyelids. It has an outer protective scleral coat modified anteriorly to form cornea The middle layer or uvea consists of the ciliary body and iris anteriorly and choroid posteriorly The innermost layer is retina containing photoreceptors which lines the posterior two-thirds of choroid. The optic nerve carries visual information to the visual cortex.