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Eye

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Nursing NAIHS

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Eye

  1. 1. Eye Maj Dr Rishi Pokhrel MBBS, MD Dept of Anatomy, NAIHS
  2. 2. Introduction • Peripheral organ of vision • Present in anterior part of orbit • 1 inch in diameter • Orbital fascia and bulbar fascia
  3. 3. Orbital fascia and bulbar fascia
  4. 4. .
  5. 5. FASCIA BULBI (Tenon's capsule) • It is a thin membrane which envelops eyeball from optic nerve to ciliary region; • allows eyeball to move freely • smooth inner surface pierced by vessels and nerves • fuses with sheath of optic nerve and sclera • lower part of membrane thickens into suspensory ligament (checks ligaments) which attaches to zygomatic arch and lacrimal bones.
  6. 6. Structure
  7. 7. Structure • Outer fibrous coat is composed of – Sclera – Cornea • Middle vascular coat comprises – Choroid – Ciliary body – Iris • Inner nervous coat consists of – Retina
  8. 8. CORNEA • half inch wide convex and transparent layer. • 5 layered • Anterior chamber separates it from iris. • avascular, nourished by lymph and aqueous humor • rich nerve supply. • Its junction with sclera is limbus.
  9. 9. SCLERA • This visible white part of the eye is covered with conjunctiva. • made up of dense fibrous tissue. • It provides attachments to tendons of recti and obliqui. • It is pierces by numerous nerves and vessels.
  10. 10. CHOROID • It lines sclera and separates it from retina. • consists of pigmented tissue containing nerve plexuses, network of capillaries, arteries and superficially veins.
  11. 11. CILIARY BODY • connects choroid with iris. • made up of ciliary processes (internally) and ciliary muscle (externally).
  12. 12. CILIARY MUSCLE • muscular ring placed deep to anterior part of sclera. • made up of radial and circular fibres. • brought into action during accommodation e.g. it slackens suspensory ligament of lens thus making it move convex as is required for near vision.
  13. 13. IRIS • placed b/w lens and cornea • circular, colored and contractile curtain. • central aperture – pupil • made up of smooth muscle called sphincter pupillae and dilator pupillae. • Decrees and increase the size of pupil - aperture
  14. 14. RETINA • Light sensitive layer • 10 layers • Cells - Rods and cones • two components. – Pigmented layer (external layer) is attached to choroid and continues over ciliary body to iris. – Retina proper (internal layer) is in contact with vitreous. Ora serrata divides it into posterior optic part and anterior ciliary part. • Ora serrata - wavy border behind the ciliary body.
  15. 15. RETINA • Macula lutea- at posterior pole of eyeball on retinal is a small yellowish spot. – It presents fovea centralis - cones
  16. 16. ROD CONE
  17. 17. • Optic disc – point where optic nerve fibers converge to leave eyeball. – 1 mm below and 3 mm medial to posterior pole. – Its circumference is raised while its centre is depressed called optic cup. – The disc is the blind spot of eye as it lacks nervous elements.
  18. 18. LENS • transparent and circular, b/w vitreous and iris • Biconvex, 10 mm in diameter and 4 mm thick. • Ciliary muscle contraction -> slackening of suspensory ligament - > thickening of lens -> near vision
  19. 19. • ANTERIOR CHAMBER • It is the space between cornea anteriorly & iris and central part of lens posteriorly • POSTERIOR CHAMBER • It is behind iris and suspensory ligament and adjoining part of lens posteriorly. The two chambers communicate through pupil; filled with a clear fluid called aqueous humor.
  20. 20. • VITREOUS HUMOUR (Vitreous body) • transparent and jelly like substance that fills posterior 4/5 of eyeball. • enclosed in a transparent membrane (hyaloid membrane)
  21. 21. CLINICAL ANATOMY Cataract • progressive condition of lens characterized by loss of transparency. • a gray-white opacity in the lens. • Congenital cataracts are usually hereditary but may be caused by viral infection during first trimester of gestation. • Senile cataracts are uncomplicated cataracts of old age. Vision is lost if cataracts are not treated.
  22. 22. Retinal detachment • separation of retina from choroid. • The retina does not contain sensory nerves; thus condition is painless. • D begins at the thin peripheral edge of retina and extends gradually beneath thicker central areas. • is not checked it results in blindness.
  23. 23. Corneal grafting (keratoplasty) • This surgical procedure of transplantation of cornea is performed to improve vision in corneal scarring, distortion or perforation.
  24. 24. Glaucoma • elevated intraocular pressure because of obstruction of outflow of aqueous humour. Glaucoma may be: – Acute (narrow angle) – Chronic (wide angle) glaucoma
  25. 25. Corneal reflex • protective mechanism for eye where eyelids close when cornea is touched. • mediated by ophthalmic division of 5th cranial nerve (sensory) and 7th cranial nerve (motor). • This reflex may be used as a test of integrity of those nerves.
  26. 26. queries
  27. 27. Ant Epithelium Bowman’s membrane Substantia propria (Stroma) Descemet’s membrane Post Epithelium / Endothelium Layers of Cornea
  28. 28. Uvea • Vascular layer • 3 Parts – Choroid – Ciliary body – Iris
  29. 29. Retina
  30. 30. Introduction • Neural Photoreceptor layer • Development – Optic vesicle - cup – Outer layer- Pigment – Inner layer- Neural – Detachment
  31. 31. ROD CONE
  32. 32. Layers • Ten layers– Outside in – Retinal Pigment epithelium – Outer segment & Inner segment - Photoreceptors – External Limiting membrane – Outer Nuclear – Outer Plexiform – Inner Nuclear – Inner Plexiform – Ganglion cell – Optic nerve fibre – Internal Limiting membrane • Mnemonic: Please Reply MY New Post, Never Pray God For Money – NB- Outside in- ? Dir light/Impulse
  33. 33. Layers Of The Retina 10 9 8 7 6 5 4 3 2 1
  34. 34. 1. Retina contains photosensitive cells. The outer limit of the retina is the Pigmented Epithelium (PEp) 1. Choroid (Ch) is a highly vascular layer containing melanocytes and separated from the retina by the epithelial basement membrane (Bruch’s membrane) 3. Sclera (S) consists of dense fibroelastic connective tissue 3 Coats Of The Eye s

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