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Questions and Answers
What are the primary symptoms associated with Posterior Vitreous Detachment (PVD)?
The primary symptoms of PVD include flashing lights (photopsia) and floaters.
What is the significance of the Shafer sign in the context of vitreous disorders?
The Shafer sign, or 'tobacco dust', indicates the presence of pigment granules in the anterior vitreous, typically seen when there has been a retinal break.
What is the recommended management protocol for a patient exhibiting high-risk features for PVD?
Patients showing high-risk features for PVD should be referred to HES for further evaluation.
Describe how vitreous hemorrhage can complicate the assessment of retinal breaks.
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What distinguishes asteroid hyalosis from other types of vitreous opacities?
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What are two common symptoms associated with vitreous disorders?
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Describe the process of posterior vitreous detachment (PVD).
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What is vitreous hemorrhage and what can cause it?
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Name two types of vitreomacular interface disorders.
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What are vitreous opacities and how do they present symptomatically?
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What are the typical causes of vitreous haemorrhage?
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How do vitreous opacities differ between synchisis scintillans and asteroid hyalosis during eye movement?
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What symptoms may indicate a severe vitreous haemorrhage?
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What is an epiretinal membrane (ERM), and how does it affect the retina?
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What is the role of ultrasound B-scan in the management of vitreous haemorrhage?
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What remnants of the hyaloid vessels are associated with persistent fetal vasculature?
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What visual symptoms can be expected with mild vitreous haemorrhage?
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In which disorders can vitreomacular interface disorders lead to the development of macular abnormalities?
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Study Notes
Vitreous Opacities
- Muscae Volitantes (Floaters): Visual effect within the eye; often described as spots, cobwebs, or flies
-
Asteroid Hyalosis: Common degenerative process; Small round yellow/white opacities (lipid & calcium particles) collect within the vitreous gel;
- May cause symptoms of Muscae Volitantes (floaters)
- May cause Photopsia (flashing lights) if there are adhesions to the retina
- Can affect vision, depending on severity & nature of the vitreo-retinal disease:
- Metamorphopsia
- Blurring/Loss of Vision
- Visual Field Defect
-
Synchisis Scintillans: Degenerative process involving cholesterol crystals in the liquified vitreous;
- Usually caused by a previous vitreous hemorrhage
- Moves more with eye movement than Asteroid Hyalosis
- Can extend into the anterior chamber
-
Vitreous Hemorrhage:
- Causes:
- Acute PVD associated with retinal tear or vessel avulsion
- Proliferative Retinopathy (DR, RVO, vasculitis, Sickle Cell)
- Miscellaneous retinal disorders (microaneurysm, telangiectasia, capillary hemangioma)
- Trauma
- Systemic (bleeding disorders)
- Symptoms:
- Mild VH - sudden onset floaters and slight blurred vision
- Severe VH - severe loss of vision
- Management
- Ultrasound B-scan (to determine the cause)
- Treatment based on the cause (may involve observation or vitrectomy)
- Causes:
-
Persistent Fetal Vasculature: Remnants of the hyaloid vessels;
- May form a Bergmeisters papilla (a small, white disc on the optic nerve head)
- May form a Mittendorf dot (a form of posterior polar cataract) on the posterior lens surface
- May result in persistent hyperplastic primary vitreous (PHPV)
Vitreomacular Interface Disorders
-
Epiretinal Membrane (ERM): Fibrocellular structure that develops on the retinal surface;
- Distorts the underlying retina
- Causes visual symptoms and development of other macular abnormalities:
- Cystoid Macular Edema (CMO)
- Holes
- Prevalence increases with age, but can be precipitated by trauma, surgery, uveitis, and PRP laser
- Macular Hole: A break in the macula
-
Vitreomacular Traction (VMT): Occurs when vitreous gel pulls on the macula;
- Often found in association with ERMs and macular holes
Posterior Vitreous Detachment (PVD)
- Liquid pockets appear in the vitreous, which coalesce and separate the vitreous from the retina
- Symptoms:
- Flashing lights (photopsia) - arc-like, more noticeable in dim illumination, usually in temporal field of vision
- Floaters - spots, cobwebs, flies
- More noticeable against a bright pale background
- Can be accompanied by blurred vision
- Signs:
- Detached hyaloid membrane
- Weiss ring near the optic disc margin
- Pigment granules in the anterior vitreous (Shafer sign “tobacco dust”)
- Larger and less reflective than red blood cells
- Significantly associated with retinal breaks
- Vitreous hemorrhage (look carefully for retinal breaks)
Posterior Vitreous Detachment (PVD): Management
- Dilate the patient's eyes.
- Schedule a dilated fundus examination within 24-48 hours (urgency based on symptom severity and risk factors)
- Low Risk: Advise patient on signs/symptoms of retinal detachments and recommend immediate reporting of these
- High Risk: Refer to the hospital emergency service for evaluation if:
- Trauma
- Shower of floaters
- Hazy vision
- High myopia with significant retinal thinning
- Suspicious signs (e.g. VH)
- Urgent referral also indicated for any suspicious signs (e.g. vitreous hemorrhage)
Optical Coherence Tomography (OCT)
- Non-invasive, high-resolution, cross-sectional imaging modality
- Highly reflective structures: drusen, microaneurysm, hard exudates, cotton-wool spots, naevus
- Low reflective structures: vitreous, oedema, intra-/sub-retinal fluid, cysts
Vitreous Pathology in Summary
- Posterior Vitreous Detachment (PVD)
- Vitreous Opacities:
- Muscae Volitantes (floaters)
- Asteroid Hyalosis
- Synchisis Scintillans
- Vitreous Haemorrhage
- Persistent Fetal Vasculature
- Vitreomacular Interface Disorders:
- Vitreomacular Traction (VMT)
- Epiretinal Membrane (ERM)
- Macular Hole
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Description
This quiz covers various types of vitreous opacities including Muscae Volitantes, Asteroid Hyalosis, Synchisis Scintillans, and Vitreous Hemorrhage. Participants will learn about their characteristics, causes, and symptoms, as well as how they may affect vision. Test your knowledge of these important eye conditions.
