Recommended
More Related Content
What's hot
What's hot (20)
Similar to DR WANI'STALK ON Anatomy, development and applied anatomy of the vitreous final july 18 of 2020
Similar to DR WANI'STALK ON Anatomy, development and applied anatomy of the vitreous final july 18 of 2020 (20)
More from vbwani
More from vbwani (9)
Recently uploaded
Recently uploaded (20)
DR WANI'STALK ON Anatomy, development and applied anatomy of the vitreous final july 18 of 2020
- 2. Vitreous or vitreous body 0The word “vitreous” is derived from a Latin word “vitrum” which means glass 7/19/2020 DR VIVEK WANI JIO TALK ON VITREOUS 2
- 3. Vitreous morphological anatomy 0It is transparent, colorless, gel like structure that occupies the space between the lens and the retina 0The space is known as vitreous cavity 0It makes 80% of the volume of the globe 0Volume is about 4 ml 7/19/2020 DR VIVEK WANI JIO TALK ON VITREOUS 3
- 4. From Tozer et al https://www.vmrinstitute.com/wp- content/uploads/2013/10/Hartnett -Ch-3.pdf 7/19/2020 DR VIVEK WANI JIO TALK ON VITREOUS 4
- 5. From Yanoff and Duker Text book 7/19/2020 DR VIVEK WANI JIO TALK ON VITREOUS 5
- 6. Vitreous body 0It is made up of >98% water 0Other important constituents are collagen and hyaluronan 0It’s AL is 16.5 mm in an emmetropic eye 0Its viscosity is 2-3 times > water 0Refractive index =1.33 =aqueous 7/19/2020 DR VIVEK WANI JIO TALK ON VITREOUS 6
- 7. Vitreous anatomy The vitreous body is composed of 2 main parts which are continuous with each other: A. Hyaloid membrane or cortex –a membrane that envelopes the vitreous body B. Vitreous central part -Central core 7/19/2020 DR VIVEK WANI JIO TALK ON VITREOUS 7
- 8. From Yanoff and Duker Text book 7/19/2020 DR VIVEK WANI JIO TALK ON VITREOUS 8
- 9. A. Hyaloid membrane Hyaloid membrane is condensation of collagen fibers that envelope and run parallel to the surface of the vitreous body Is divided in to two parts a) Anterior hyaloid -anterior to the vitreous base b) Posterior hyaloid membrane that is posterior to the vitreous base 7/19/2020 DR VIVEK WANI JIO TALK ON VITREOUS 9
- 10. From Yanoff and Duker Text book 7/19/2020 DR VIVEK WANI JIO TALK ON VITREOUS 10
- 11. What is the vitreous base 0The vitreous base is portion of the vitreous that straddles the ora serrata It extends 1-2 mm anteriorly in to the pars plana 1-3 mm posterior to the ora in to anterior retina 0The vitreous cortex is strongly adherent to the underlying retina, ora and pars plana at the vitreous base 0 it cannot be detached7/19/2020 DR VIVEK WANI JIO TALK ON VITREOUS 11
- 12. a) Anterior vitreous face and its relations 0 The central part of anterior face is called patellar fossa a concave part that accommodates the lens 0 The anterior hyaloid membrane is adherent in a circular fashion to the posterior capsule of the lens at a diameter of about 9 mm 0 This adhesion is known as Weiger ligament or hyaloideo-capsular ligament or Egger’s line 0 This attachment is very strong in young age and becomes weaker with age 7/19/2020 DR VIVEK WANI JIO TALK ON VITREOUS 12
- 13. From Yanoff and Duker Text book 7/19/2020 DR VIVEK WANI JIO TALK ON VITREOUS 13
- 14. a) Spaces and canals of anterior vitreous face 0 Berger’s space gap between the anterior vitreous face and posterior surface of the lens internal to the Weiger ligament ( Erggelet’s line) 0 The anterior vitreous face continues outward from Weiger ligament, crosses the zonular body and pars plana and ends at the anterior border of the vitreous base 7/19/2020 DR VIVEK WANI JIO TALK ON VITREOUS 14
- 15. a) Spaces and canals of anterior vitreous face 0Canal of Petit- the space between anterior vitreous face and zonular body 0Sometimes intravitreal injection of gas during pneumoretinopexy can enter Petit’s space and forms a donut shaped gas entrapped in this space7/19/2020 DR VIVEK WANI JIO TALK ON VITREOUS 15
- 16. From Entokey website7/19/2020 DR VIVEK WANI JIO TALK ON VITREOUS 16
- 17. Anterior vitreous face 0 There is an opening in the center of Berger space which opens in to a narrow transparent canal that traverses through the vitreous body in a S shaped manner posteriorly to attach to the margins of the ONH 0 This canal is known as Cloquet’s canal formed by collagen fibers surrounding this space 0 There are no collagen fibers in the canal and is the embryological remnant of hyaloid artery 0 It’s attachment to the ONH encloses a space shaped like a funnel known as space of Martegiani 7/19/2020 DR VIVEK WANI JIO TALK ON VITREOUS 17
- 18. From Entokey website7/19/2020 DR VIVEK WANI JIO TALK ON VITREOUS 18
- 19. b) Posterior vitreous face or posterior hyaloid membrane 0 It starts from the posterior border of the vitreous base and envelopes the vitreous and ends around the edge of ONH 0 It is loosely adherent to the inner limiting membrane (ILM)of the retina 0 It is absent over the ONH 0 It is condensation of collagen fibers that run parallel to the surface of the vitreous body 7/19/2020 DR VIVEK WANI JIO TALK ON VITREOUS 19
- 20. b) Normal attachments of the posterior vitreous face 0Around the borders of the ONH 0To the retina around the macula in a circular fashion at 3 mm diameter 0Over the retinal blood vessels 0At the vitreous base posterior border 7/19/2020 DR VIVEK WANI JIO TALK ON VITREOUS 20
- 21. 0The posterior vitreous face is in contact with internal limiting membrane of the retina 0The attachment between posterior hyaloid and ILM is supposed to be with glue like substance made up of connecting proteins like laminin and fibronectin 0The attachment of posterior hyaloid to ILM is strong in younger individuals b) Normal attachments of the posterior vitreous face 7/19/2020 DR VIVEK WANI JIO TALK ON VITREOUS 21
- 22. Micro structure of the vitreous 0 Vitreous is made up of collagen, water, hyaluronan, chondroitin sulfate and cells 0 Collagen fibers are of type II(75%), a hybrid of type V/XI 10% and type IX 15% 0 The hyaluronon molecules occupy space between the collagen fibres and bind water molecules 0 The negatively charged Hyaluronan and positively charged collagen form electrostatic binding ensuring swollen nature of the vitreous gel and separation of the collagen fibers 7/19/2020 DR VIVEK WANI JIO TALK ON VITREOUS 22
- 23. Micro structure of the vitreous 0 The Collagen IX with chondroitin sufate molecules holds the fibers away from each other thus separating them for transparency 0 The collagen fibers need to be separated by at least one wavelength of incident light to prevent light scattering allowing light transmission through the vitreous 0 Its production is stops in early life 7/19/2020 DR VIVEK WANI JIO TALK ON VITREOUS 23
- 24. Hyaluronan 0It is unbranched polymer of repeating acetyl glucosamine disachharide molecule 0It has tremendous capacity to hold water 0In unhydrated state a molecule has volume of 0.63 cm3/gm and in hydrated state it is 2000- 3000 cm3/gm 0It is continuously produced by hyalocytes and leaves the vitreous through aqueous 7/19/2020 DR VIVEK WANI JIO TALK ON VITREOUS 24
- 25. How are the collagen fibers arranged in cortex, vitreous base and core? Posterior Cortex 0 It is 100-110 micron thick made up sheets of collagen fibers 0 Thinner over macula and is absent over the ONH 0 Bundles of collagen fibers start from the posterior border of the vitreous base run parallel to retinal surface and run circumferentially 0 The fibers are continuous and do not branch 7/19/2020 DR VIVEK WANI JIO TALK ON VITREOUS 25
- 26. From Tozer et al https://www.vmrinstitute.com/wp- content/uploads/2013/10/Hartnett -Ch-3.pdf 7/19/2020 DR VIVEK WANI JIO TALK ON VITREOUS 26
- 27. How are the collagen fibers arranged in cortex, vitreous base and core? 0The posterior hyaloid is adherent to retina strongly in younger age and loosens in older age 0The adhesion is through a glue like substance made up of laminin and fibronectin 0The cortex also contains hyalocytes which have function of producing hyaluronan and phagocytic and immunologic function 7/19/2020 DR VIVEK WANI JIO TALK ON VITREOUS 27
- 28. Collagen fibers in the core 0The collagen fibers are less in number and run parallel to the Cloquet canal 0Hyalocytes are not present in the core vitreous 0There is more water and hyaluronan than collagen 7/19/2020 DR VIVEK WANI JIO TALK ON VITREOUS 28
- 29. Structure of the vitreous Vitreous base 0 The vitreous base is the place of strongest adhesion of vitreous 0 Vitreous base is 3 dimensional structure 0 It has 4-5 mm width- 1-2 mm anterior to ora and 2-3 mm posterior to the ora 0 It also extends inwards in to the vitreous 0 The collagen fibers are denser and more in number here 7/19/2020 DR VIVEK WANI JIO TALK ON VITREOUS 29
- 30. From Tozer et al https://www.vmrinstitute.com/wp-content/uploads/2013/10/Hartnett-Ch- 3.pdf 7/19/2020 DR VIVEK WANI JIO TALK ON VITREOUS 30
- 31. Structure of the vitreous base 0 The heavy bundles of collagen fibers in the vitreous base vertically attach or insert in to the basal lamina of retinal glial cells posterior to the ora 0 And the collagen fibers interdigitate with basement membrane of the ciliary body epithelium anterior to the ora serrata 0 This is the basis of strong adhesion between the vitreous base and retina 0 Whereas in the collagen fibers run parallel to the retina and donot attach or insert in to the ILM 7/19/2020 DR VIVEK WANI JIO TALK ON VITREOUS 31
- 32. Vitreous cells or Hyalocytes 0Vitreous is mainly acellular 0Hyalocytes are found in cortical vitreous 0Hyalocytes are basically mononuclear phagocytes or macrophages 0They produce hyaluronan 0Few fibrocytes and glial cells are also seen in vitreous 7/19/2020 DR VIVEK WANI JIO TALK ON VITREOUS 32
- 33. From Tozer et al https://www.vmrinstitute.com/wp-content/uploads/2013/10/Hartnett-Ch- 3.pdf 7/19/2020 DR VIVEK WANI JIO TALK ON VITREOUS 33
- 34. Development of vitreous Recognized to take place in two stages. The stages are overlapping Primary vitreous Secondary vitreous Tertiary vitreous is actually zonular fibres which is part of ciliary body development 7/19/2020 DR VIVEK WANI JIO TALK ON VITREOUS 34
- 35. From Snell & Lemp 7/19/2020 DR VIVEK WANI JIO TALK ON VITREOUS 35
- 36. Primary Vitreous 0 Starts as early as 4 th week of gestation 0 It develops between the developing lens and the developing retina 0 Contributed by neuroectoderm, surface ectoderm and mesenchyme a) neuroectoderm of retinal layer and ectoderm of the lens epethelium initially produce delicate cytoplasmic processes in the space between lens and invaginating optic cup b) Mesenchyme tissue that forms the hyaloid artery system enters through the optic fissure7/19/2020 DR VIVEK WANI JIO TALK ON VITREOUS 36
- 37. From Williams and Cook -Eyenews 7/19/2020 DR VIVEK WANI JIO TALK ON VITREOUS 37
- 38. Primary Vitreous 0 The mesenchymal tissue enters the primary vitreous at around 5th week of GA through the optic or choroidal fissure and forms hyaloid artery and branches and forms capillary network in the vitreous 0 This is called vasa hyaloidea propria 0 It communicates with vascular network around the lens-tunica vasculosa lentis 0 Fibroblasts from mesenchyme enter the primary vitreous and contribute to collagen formation 0 So primary vitreous is vascular and cellular 7/19/2020 DR VIVEK WANI JIO TALK ON VITREOUS 38
- 39. From Snell & Lemp 7/19/2020 DR VIVEK WANI JIO TALK ON VITREOUS 39
- 40. From Tozer et al https://www.vmrinstitute.com/wp-content/uploads/2013/10/Hartnett-Ch- 3.pdf 7/19/2020 DR VIVEK WANI JIO TALK ON VITREOUS 40
- 41. From Snell & Lemp 7/19/2020 DR VIVEK WANI JIO TALK ON VITREOUS 41
- 42. Primary Vitreous 0The vasa hyaloidea propria starts disappearing with appearance of secondary vitreous 0The fetal fissure starts closing from 5th week and the closure is complete by 7 th week 0The eye becomes a closed system 7/19/2020 DR VIVEK WANI JIO TALK ON VITREOUS 42
- 43. From Snell & Lemp 7/19/2020 DR VIVEK WANI JIO TALK ON VITREOUS 43
- 44. Secondary vitreous 0 This is the stage of formation of homogenous, acellular vitreous which is made up of type II collagen and hyaluronic acid 0 It starts to appear between retina and the posterior vaso hyaloidea propria 0 It starts at 6 week of gestation 0 The secondary vitreous pushes and encircles the primary vitreous pushing it forward and center 7/19/2020 DR VIVEK WANI JIO TALK ON VITREOUS 44
- 45. From Snell & Lemp 7/19/2020 DR VIVEK WANI JIO TALK ON VITREOUS 45
- 46. Secondary Vitreous 0 Hyalocytes, derived from the mesenchyme around the hyaloid vessels and possibly from blood-derived monocytes, now migrate into the definitive vitreous 0 The vasa hyaloidea propria of primary vitreous which is very prominent at around 9 week of GA starts disappearing gradually by atrophy 0 The border between the primary and secondary vitreous form the Weiger ligament anteriorly 7/19/2020 DR VIVEK WANI JIO TALK ON VITREOUS 46
- 47. Secondary vitreous 0 Cloqeuet canal appears when the hyaloid artery atrophies 0 Secondary vitreous is clear vitreous that is seen in adults 0 The collagen and hyaloronic acid are supposed to be produced by hyalocytes 0 The hyaluronic acid greatly enlarges the vitreous thus swelling it in size and helping the eye to grow 7/19/2020 DR VIVEK WANI JIO TALK ON VITREOUS 47
- 48. Applied Anatomy of the Vitreous 0We will deal with common conditions that have relation with anatomy of vitreous 0We will not deal with inherited conditions or all vitreal diseases 7/19/2020 DR VIVEK WANI JIO TALK ON VITREOUS 48
- 49. I) Importance of anterior hyaloid membrane 0 During anterior segment surgeries there may be violation of the anterior hyaloid membrane –cataract surgery 0 Then the fluid enters the vitreous through an opened anterior hyaloid and the pressure in vitreous increases 0 It allows the vitreous to enter AC and then prolapse out of eye through the surgical wound 7/19/2020 DR VIVEK WANI JIO TALK ON VITREOUS 49
- 50. Consequences of vitreous in wound 0 If proper anterior vitrectomy is not done to clear all prolapsed vitreous then vitreous in wound or AC may lead to delay in wound healing vitreous wick syndrome-iridocyclitis, CME Vitreous touch to cornea and endothelial damage Endophthalmitis Vitreous traction on retina leading to retinal tears and RD 7/19/2020 DR VIVEK WANI JIO TALK ON VITREOUS 50
- 51. Consequences of rupture of anterior hyaloid face IN patients with diabetes 0Worsening of DR and macular edema 0Neovascular glaucoma 7/19/2020 DR VIVEK WANI JIO TALK ON VITREOUS 51
- 52. Anterior Vitreous examination 0Anterior retrolental vitreous is usually optically empty 0Any cells in it indicate inflammation or tumors or hemorrhage 0Pigments in anterior vitreous known as Shaffer’s sign may indicate a retinal tear 7/19/2020 DR VIVEK WANI JIO TALK ON VITREOUS 52
- 53. II) Vitreous base and surgical importance a) Site of intravitreal injection and entry for pars plana vitrectomy The vitreous base straddles the ora serrata 1-2 mm anterior to it and 1-3 mm posterior to it When entering the vitreous we have to avoid the pars plicata which is vascular and avoid injuring the lens in phakic eye-so we have to go posterior We want to avoid the entering the eye through the vitreous base which is around 1-2 mm anterior to the ora 7/19/2020 DR VIVEK WANI JIO TALK ON VITREOUS 53
- 54. B) Vitreous base and surgical importance Pars plicata first 2 mm from limbus vascular so avoid After 2 mm up to 6 mm is pars plana ideal as no bleeding Vitreous base occupies about 1-2 mm of posterior pars plana So 4 mm in phakic eyes avoids injuring the lens and also avoids passing through the vitreous base In aphakic and pseudophaic eyes it is at 3.5 mm Passing through the vitreous base may distort it and exert traction on its posterior margin causing retinal breaks during intravitreal injections or while passing the trocars for pars plana vitrectomy 7/19/2020 DR VIVEK WANI JIO TALK ON VITREOUS 54
- 55. SITE OF ENTRY FOR PPV OR IVI 7/19/2020 DR VIVEK WANI JIO TALK ON VITREOUS 55
- 56. Passing the blade through the vitreous base can cause tears 7/19/2020 DR VIVEK WANI JIO TALK ON VITREOUS 56
- 57. III) Posterior hyaloid A-SURGICAL 0 Removal of posterior hyaloid is the most important step of any vitrectomy surgery 0 PVD is difficult to achieve in very young patients but much easier in older individuals if it is not detached already 0 The posterior hyaloid is detached near the disc and lifted till the vitreous base and we stop here 0 If we try to lift it further we will cause tears at vitreous base 7/19/2020 DR VIVEK WANI JIO TALK ON VITREOUS 57
- 58. Posterior hyaloid B) Vitreous degeneration and posterior vitreous detachment b) Posterior vitreous detachment The vitreous undergoes degeneration resulting in separation of collagen fibers from hyaluronan The gel portion of vitreous becomes less with age This results in condensation of vitreous fibers and appearance of lacunae of clear vitreous where collagen fibers are absent Condensed vitreous fibers cause floaters 7/19/2020 DR VIVEK WANI JIO TALK ON VITREOUS 58
- 59. Liquefaction of vitreous – synchisis 0 From Duanes text book 7/19/2020 DR VIVEK WANI JIO TALK ON VITREOUS 59
- 60. 0 From Duanes text book 7/19/2020 DR VIVEK WANI JIO TALK ON VITREOUS 60
- 61. B) Vitreous base and PVD b) Vitreous base –may extend posteriorly in tongue shaped manner with age or in patients with myopia This has a role to play in the development of retinal tears during PVD 7/19/2020 DR VIVEK WANI JIO TALK ON VITREOUS 61
- 62. Abnormal strong adhesions of vitreous to retina 0 Margins of lattice degeneration 0 Chorioretinal scars 0 Posterior extensions of vitreous base 0 WWP 0 Abnormal strong adhesions will result in retinal breaks or avulsed vessels causing vitreous hemorrhage or retinal hgs when PVD occurs 7/19/2020 DR VIVEK WANI JIO TALK ON VITREOUS 62
- 63. C) POSTERIOR VITREOUS DETACHMENT- PVD 0 PVD is separation of the posterior vitreous cortex from the ILM 0 This usually occurs after substantial liquefaction of the vitreous (synchisis) 0 The loculi or areas of liquefaction in the vitreous coalesce 0 A break occurs in the posterior vitreous surface through which the fluid escapes 0 The vitreous body collapses-syneresis 0 The escaped fluid dissects the vitreous cortex from the retina in all quadrants up to posterior border of the vitreous base where it is firmly attached to the retina 7/19/2020 DR VIVEK WANI JIO TALK ON VITREOUS 63
- 64. PVD 0 PVD is diagnosed by visualizing the posterior vitreous face and the Weiss ring –a glial ring detached from the edge of the ONH 7/19/2020 DR VIVEK WANI JIO TALK ON VITREOUS 64
- 65. PVD 7/19/2020 DR VIVEK WANI JIO TALK ON VITREOUS 65
- 66. PVD 0Usually occurs between 45- 65 YRS 0Increases with ageing 0Early in myopes, uveitis and trauma cases 7/19/2020 DR VIVEK WANI JIO TALK ON VITREOUS 66
- 67. Sequel of PVD 0 Retinal tears 0 Vitreous hemorrhage 0 Vitreous haze or clouding Retinal tears occur at Posterior border of the vitreous base where there may be localized posterior extension of the base Posterior margin or side of lattice degeneration Abnormal vitreo-retinal adhesions that may or may not be visible pre PVD 7/19/2020 DR VIVEK WANI JIO TALK ON VITREOUS 67
- 68. Sequel of PVD 0 PVD may also cause avulsion of superficial retinal blood vessels, pre-papillary vessels and vessels crossing the torn retina causing retinal and vitreous hemorrhages 7/19/2020 DR VIVEK WANI JIO TALK ON VITREOUS 68
- 69. PVD 7/19/2020 DR VIVEK WANI JIO TALK ON VITREOUS 69
- 70. 7/19/2020 DR VIVEK WANI JIO TALK ON VITREOUS 70
- 71. 7/19/2020 DR VIVEK WANI JIO TALK ON VITREOUS 71
- 72. Anomalous PVD 0 An anomalous PVD is defined as a partial vitreous detachment with persistent attachment in the macular region featuring an anomalous strength of adhesion to 1 or more structures in the posterior pole, resulting in tractional deformation of retinal tissue Ophthalmology 2013;120:2611-2619 7/19/2020 DR VIVEK WANI JIO TALK ON VITREOUS 72
- 73. 7/19/2020 DR VIVEK WANI JIO TALK ON VITREOUS 73
- 74. 7/19/2020 DR VIVEK WANI JIO TALK ON VITREOUS 74
- 75. 7/19/2020 DR VIVEK WANI JIO TALK ON VITREOUS 75
- 76. 0 Such tractional changes in the macula are called vitreomacular traction syndromes They cause symptoms like metamorphopsias, decreased vision and difficulty in reading and near work 7/19/2020 DR VIVEK WANI JIO TALK ON VITREOUS 76
- 77. VMT 7/19/2020 DR VIVEK WANI JIO TALK ON VITREOUS 77
- 78. 7/19/2020 DR VIVEK WANI JIO TALK ON VITREOUS 78
- 79. 7/19/2020 DR VIVEK WANI JIO TALK ON VITREOUS 79