Vitreous (Attachments, age changes, vitreous hemorrhage, Vitreous Detachment)

Vitreous (Attachments, age changes, vitreous hemorrhage, Vitreous Detachment)

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  VITEROUS Attachments, age changes,vitreous hemorrhage, Vitreous Detachment MARYAM FIDA Optometry and orthoptics Vitreous
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  Vitreous Vitreous is aninert, avascular, transparent, jelly like structure. Serve as one of refractive media of the eye and has optical functions. It gives structural integrity to eye and provide nutrients to the lens, ciliary body and retina. Constitute 80% volume of the eye. Contain collagen fibrils, mucopoly-saccharides and hyaluronic acid. It’s a hydrophilic gel which become ‘’fluid’’ when protein coagulates. Reasons for coagulation of proteins could be,  Advancing senile age  Degenerations, e.g. as in high myopia  Chemical and mechanical trauma Internal limiting membrane on inner surface of retina separate it from vitreous. There is potential space ‘subhyaloid space’ between two. Figure 1 structures of vitreous Vitreous attachments
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  1. Anteriorly tothe lens and ciliary epithelium in front of ora serrata. Part of vitreous about 4mm across ora serrata is called as ‘base of vitreous’. Here, attachment is strongest. 2. Posteriorly to the edge of optic disc and macula lutea (foveal region) forming ring shaped structure around them. Figure 2 vitreous attachments Age changes in Vitreous Vitreous undergo certain physical and biochemical changes with aging. 1. At birth_ the Cloquet’s canal runs straight from lens to optic disc. It contains primary vitreous. 2. In young persons_ vitreous gel is homogenous but its fibers become coarse with process of advancing age. 3. In old age and high myopes_ secondary vitreous liquified (syneresis) and shrinks, producing a vitreous detachment, vitreous and retinal hemorrhage and retinal break.
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  Figure 3 Vitreousatbirth Figure 4 Vitreous in young adults. Figure 5 vitreousdetachmentin old age Vitreous Hemorrhage Vitreous hemorrhage is the extravasation, or leakage, of blood into the areas in and around the vitreous humor of the eye. TYPES There are two types of vitreous hemorrhage. 1. Peripheral or subhyaloid hemorrhage _ occurs between retina and vitreous. Blood remains fluid, red in color Blood moves with gravity forming boat-shaped figure in macular area. Figure 3 subhyaloid hemorrhage 2. Intravitreal hemorrhage_ the hemorrhage may get absorbed or degenerate to form a white fibrous tissue mass. Etiology
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  Common causes ofvitreous hemorrhage are; i. Trauma_ by contusion or penetrating injury ii. Vitreous retraction_ vitreous fibrous bands or membrane retraction iii. Eale’s disease_ due to retinal vasculitis and periphlebitis iv. Blood dyscrasias_ leukemia, sickle cell anemia, purpura. v. Diabetes mellitus_ common in diabetic proliferative retinopathy vi. Central retinal vein thrombosis vii. Malignant hypertension_ often results in large intravitreal hemorrhage. Symptoms I. Black spots or clouds maybe seen in front of eye. II. Impaired vision maybe up to perception of light. Signs 1. Fundus examination a) Faint or no red reflex seen b) Grey opacities maybe present in vitreous Figure 4 (A) Fundus examination revealed hemorrhage of the retinal vein (arrow). (B) Retinal hemorrhage spontaneously disappeared in 1 weekafter the discontinuation of regorafenib treatment. 2. Slit-lamp examination Fresh blood or clotted blood is seen in vitreous. Figure 5 large intravitreal hemorrhage Vitreous Detachment
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  A vitreous detachmentis a condition in which vitreous shrinks and separates from the retina. Types of detachment 1. Posterior vitreous detachment(PVD) Separation of cortical vitreous from retina anywhere posterior to vitreous base Synchysis_ associated vitreous liquification Syneresis_ collapse of vitreous due to collection of synchytic fluid between posterior hyaloid membrane and internal limiting membrane of retina. Incidence a) Common above age of 65 years b) May occur in eyes with senile liquefaction with development of a hole in posterior hyaloid membrane, e.g. aphakia, high myopia. Symptoms  Photopsia or flashes of light  Floaters seen Signs  Biomicroscopic examination show collapsed vitreous behind lens.  There is optical clear spacebetween detached posterior hyaloid phase and retina.  An annular opacity (Weiss rings or Fuch’s ring) ring shaped detachment of vitreous to optic disc indicate PVD. Figure 6 1Posterior vitreous detachment (PVD) 2. Detachment of vitreous base and Anterior vitreous Usually occur after blunt trauma.
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  Maybe associated vitreoushemorrhage, anterior retinal dialysis and dislocation of lens. MULTIPLE CHOICE QUESTIONS 1) Hyaluronic acid is found in? a. Vitreous humor b. Synovial fluid c. Cartilage d. Cornea 2) The most common cause of vitreous hemorrhage in adults is? a. Retinal hole Figure 7 Diagram illustrating the concept of dynamic vitreoretinal traction after posterior vitreous detachment and how this generates a flap-tear or an operculated tear. In contrast with a dialysis the vitreous remains attached and there is no posterior vitreous
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  b. Trauma c. Hypertension d.Diabetes *(trauma is most common cause of vitreous hemorrhage in young adults) 3) Black floaters in a diabetic patient indicate? a. Vitreous hemorrhage b. Maculopathy c. Vitreous infarction d. Post vitreous detachment 4) The Cortical Vitreous (differing relative density) does not cover what 2 sites? a) Ora serrata, fovea b) Fovea, Optic nerve head c) Posterior pole, Optic nerve head d) Peripheral retina, fovea 5) Order the Vitreous attachments from STRONGEST to WEAKEST a) Vitreous base, optic nerve head, posterior lens surface, retinal vessels, macula b) optic nerve head, posterior lens surface, macula, retinal vessels, Vitreous base c) Vitreous base, posterior lens surface, optic nerve head, macula, retinal vessels d) posterior lens surface, macula, retinal vessels, Vitreous base, optic nerve head. 6) Which zone of embryologic origin forms the hyaloid artery and its branches (vasa hylodea propria)? a) Secondary vitreous b) Primary vitreous c) Tertiary vitreous d) Medullary vitreous 7) Ora serrata: a) forms the boundary between the retina and the ciliary body b) is closer to the Schwalbe's line temporally than nasally c) forms part of the pars plana d) does not contain photoreceptors e) is loosely adherent to the vitreous *(forms boundary b/w retina and pars plana, contain photoreceptors, attach firmly to vitreous, and forms base of vitreous) 8) bleeding between retina and vitreous is _____? In which blood remains fluid, red in color and form boat-shaped figure in macular area. a) Vitreous loss
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  b) Inflammation ofvitreous c) Subhyaloid hemorrhage d) Intravitreal hemorrhage *(white fibrous tissue forms in intravitreal hemorrhage.) 9) Incidence of vitreous detachment is more likely a) In adulthood b) Congenital c) Below 5-8 years d) Above 65 years 10) Separation of _____ vitreous from retina is PVD? a) Apical b) Basal c) Cortical d) Apex and cortex