Embryology of eye


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My first presentation in my department ,.. Elementary and very important to proceed with the subject,..

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Embryology of eye

  1. 1. Rajvin Samuel Ponraj
  2. 2. <ul><li>Embryogenesis : </li></ul><ul><li>Organisation and development of the primary layers of the developing embryo </li></ul><ul><li>After fertilization - sequential formation </li></ul><ul><li>of three cell masses </li></ul>
  3. 4. <ul><li>Organogenesis: </li></ul><ul><li>process in which segregatory cells become rudimentary organs </li></ul>
  4. 5. Derivatives of embryonic tissues <ul><li>Neural Crest </li></ul>
  5. 6. <ul><li>Neural crest </li></ul><ul><li>Corneal keratocytes, </li></ul><ul><li>Cornea endothelium </li></ul><ul><li>Trabecular meshwork, </li></ul><ul><li>Stroma of the iris and choroid, </li></ul><ul><li>Ciliary muscle, </li></ul><ul><li>Fibroblasts of the sclera, the vitreous, and the optic nerve meninges., </li></ul><ul><li>Extraocular muscles, </li></ul><ul><li>Subepidermal layers of the eyelids. </li></ul>
  6. 7. <ul><li>Surface ectoderm </li></ul><ul><li>lens </li></ul><ul><li>the lacrimal gland </li></ul><ul><li>the epithelium of the cornea </li></ul><ul><li>conjunctiva </li></ul><ul><li>epidermis of the eyelids </li></ul>
  7. 8. <ul><li>Neuro ectoderm </li></ul><ul><li>optic vesicle and optic cup </li></ul><ul><li>Retinal pigment epithelium </li></ul><ul><li>Ciliary epithelium </li></ul><ul><li>Iris muscles </li></ul><ul><li>optic nerve fibers and glia. </li></ul>
  8. 9. <ul><li>Mesoderm </li></ul><ul><li>Vitreous </li></ul><ul><li>Extra ocular & lid muscles </li></ul><ul><li>Orbital and ocular vascular endothelium </li></ul>
  9. 10. <ul><li>3 to 4 week stage of embryo </li></ul>
  10. 11. 2 nd month stage of embryo
  11. 12. j 3 rd month stage of embryo
  12. 13. 4 th month stage of embryo
  13. 14. 5 th month to birth
  14. 15. At birth : <ul><li>Anterior – posterior diameter : 16.5 mm </li></ul><ul><li>Anterior chamber – shallow </li></ul><ul><li>Lens - spherical </li></ul><ul><li>Cornea diameter = 10 mm </li></ul><ul><li>Orbit is divergent to 50 degrees </li></ul><ul><li>Myelination occurs till lamina cribrosa </li></ul><ul><li>Retina except macula is fully differentiated </li></ul><ul><li>and formed </li></ul>
  15. 16. Post natal period : <ul><li>Fixation completed by 6 months </li></ul><ul><li>Macula formed by 6 months </li></ul><ul><li>Steropsis and accomadation by 6 months </li></ul><ul><li>Cornea reaches adult size by 2 years </li></ul><ul><li>Lens develops throughout life </li></ul>
  16. 17. RETINA <ul><li>It develops from the optic cup. </li></ul><ul><li>The outer layer of the optic cup is the pigment layer. </li></ul><ul><li>The neural layer is formed from the inner layer of the optic cup. </li></ul>
  17. 18. MACULA <ul><li>It develops as a result of localized increase of superimposed nuclei in the ganglion cell layer, lateral to the optic disc. </li></ul>
  18. 19. Optic nerve <ul><li>Develops from glial cells of neuro ectodermal cells and axons fron ganglion cells with meningeal coverings forming the optic nerve sheets </li></ul>
  19. 20. Lens <ul><li>The posterior wall begin to elongate anteriorly and form long fibers that gradually fill the lumen of the vesicle. </li></ul><ul><li>The secondary lens fibres start from equator region elongate towards anteriorly and soon detach to form the next lens fibre layer </li></ul>
  20. 22. <ul><li>Migration of neural crest cells </li></ul><ul><li>1 st wave – corneal and trabecular </li></ul><ul><li>endothelium </li></ul><ul><li>2 nd wave - corneal stroma </li></ul><ul><li>3 rd wave - Iris stroma </li></ul>
  21. 23. Vitreous <ul><li>Primary vitreous </li></ul><ul><li>Secondary vitreous </li></ul><ul><li>Tertiary vitreous </li></ul>
  22. 24. <ul><li>SCLERA : </li></ul><ul><li>This tough outer fibrous coat is formed from the condensation of the mesenchyme around the optic cup </li></ul><ul><li>CHOROID: </li></ul><ul><li>This inner vascular layer is formed from the mesenchyme surrounding the optic vesicle. </li></ul>
  23. 25. <ul><li>Ciliary glands and eyelashes develop as outgrowths of epithelial buds </li></ul><ul><li>Eyelid develop from surface ectoderm </li></ul><ul><li>Lacrimal glands develop as ectodermal buds </li></ul><ul><li>superolaterally into mesenchyme </li></ul>
  24. 26. <ul><li>Lacrimal sac and nasolacrimal duct develop from ectoderm - nasolacrimal furrow which gets burried into a cord </li></ul>
  25. 27. Summary of various part of the eye ball. Part Derived from Lens Surface ectoderm Retina Neuroectoderm (optic cup) Vitreous Mesoderm Choroid Mesoderm (infiltrated by neural crest cells?) Ciliary body Mesoderm Ciliary muscles Mesenchymal cells covering the developing ciliary body (neural crest) Iris Mesoderm Muscles of the iris Neuroectoderm (from optic cup) Sclera Mesoderm (infiltrated by neural crest cells?) Cornea Surface epithelium by ectoderm, substantia propria and inner epithelium by neural crest Conjunctiva Surface ectoderm Blood vessels mesoderm Optic nerve Neuroectoderm. Its covering (pia, arachnoid and dura) are derived from mesoderm
  26. 28. <ul><li>THANK YOU </li></ul>