Diseases of the vitreous body

The vitreous body is the transparent, gelatinous substance that fills the space of the eye between lens and retina. It allows light to pass from the lens to the retina and normally has enough mass to maintain the eyeball's spherical shape and counteract retinal detachment. This article covers the most common diseases of the vitreous body, including posterior vitreous detachment and vitreous hemorrhage.
Posterior vitreous detachment is the separation of the posterior vitreous cortex from the internal limiting membrane of the retina. Etiologies include age-related degeneration of the vitreous tissue, elongation of the ocular bulb, and eye injuries. Patients are usually asymptomatic, but may complain of floaters and photopsia. Vitreous detachment is confirmed on slit lamp examination. Asymptomatic individuals do not require treatment. Symptomatic individuals with retinal injury (e.g., retinal tears/holes, retinal detachment) require prompt treatment with, e.g., laser photocoagulation.
Vitreous hemorrhage is the extravasation of blood into the vitreous body and its adjacent structures. It can be caused by trauma and a variety of diseases, e.g., proliferative diabetic retinopathy, posterior vitreous detachment, and tumors. Clinical features include painless sudden onset of unilateral floaters and/or visual loss. Slit lamp examination confirms the presence blood in the vitreous body. Initially, a wait-and-see approach is recommended, since the condition typically resolves spontaneously. However, if the retina is affected or severe disease progression occurs, vitrectomy is indicated.

• Definition: detachment of the posterior vitreous cortex from the internal limiting membrane of the retina
• Epidemiology: peak incidence between 45–65 years of age
• Etiology
  • Age-related degenerative liquefaction and collapse of the vitreous body (most common cause)
  • Myopia
  • Eye injury
  • Chorioretinitis
  • Aphakia (absence of the lens)
• Clinical features
  • Patients are usually asymptomatic
  • Photopsia: A sudden and brief perception of bright flashes of light that often start in one area of the visual field. It usually is unilateral and occurs in the dark or with closed eyes.
  • Floaters
• Diagnostics
  • Slit lamp examination: detached posterior surface of the vitreous becomes visible as thin irregular ring (Weiss ring)
• Treatment
  • Treatment is not necessary in patients without retinal injury and/or patients in whom symptoms resolve
  • Symptomatic patients with retinal injury require prompt treatment (see complication below)
• Complications
  • Retinal tears/holes
  • Rhegmatogenous retinal detachment
  • Vitreous hemorrhage

The sudden onset of floaters and/or the perception of flashes require urgent examination of the ocular fundus to rule out retinal injury!

References:^[1]

• Definition: the extravasation of blood in and around the vitreous body
• Etiology:
  • Rupture of neovascular vessels in ischemic changes of the retina
    • Proliferative diabetic retinopathy (most common cause)
    • Sickle cell retinopathy
    • Ocular ischemic syndrome
    • Retinopathy of prematurity
    • Retinal vein occlusion
    • Age-related macular degeneration
  • Rupture of physiological vessels
    • Lesions of the retina in symptomatic posterior vitreous detachment
    • Retinal tear
    • Blunt or penetrating traumatic injuries to the sclera or retina
    • Increased intracranial pressure, e.g., in subarachnoid hemorrhage (Terson syndrome)
  • Hemorrhage from an adjacent site
    • Retinal macroaneurysm
    • Choroidal neovascularization
    • Tumors
• Clinical features
  • Sudden onset of symptoms: usually unilateral and painless
  • Floaters and/or visual loss: typically worse after sleep
• Diagnostics
  • Slit lamp examination
    • Blood between the posterior vitreous base and internal limiting membrane
    • Can determine the source of vitreous hemorrhage (e.g., retinal neovascularization)
  • Ocular B-scan ultrasonography if blood completely obscures the posterior segment of the eye
• Treatment
  • Since hemorrhage may resolve spontaneously, a wait-and-see approach is recommended at the beginning of treatment.
  • Treatment of the underlying cause
    • If severe disease progression/retinal detachment occurs: vitrectomy
      • Surgical removal of the vitreous humor and temporary filling of the eye with liquid silicone, saline, or gas to replace the vitreous humor
    • Photocoagulation for retinal breaks or proliferative retinal vascular disease

References:^[2][3]

• Definition: hemorrhage between the retina and the posterior vitreous membrane
• Etiology
  • Microangiopathy/neovascularization (e.g., in proliferative diabetic retinopathy)
  • Disorders of hemostasis and fibrinolysis
• Clinical features
  • Sudden onset of black opacities and/or visual loss
  • Hyphema
• Diagnostics
  • Slit lamp examination
    • Well-demarcated boat-shaped hemorrhage in the posterior eye segment
    • Blood in the potential space between the internal limiting membrane and the retina
  • Ocular B-scan ultrasonography if blood completely obscures the posterior segment of the eye
• Treatment
  • Laser hyaloidotomy: opening of the vitreous body's hyaloid membrane → blood distribution by diffusion
  • Pars plana vitrectomy: surgical procedure in which the vitreous gel is removed from the eye by introducing the instruments through the pars plana

References:^[3]

• Definition: persistent embryonic tissue, which blocks the light passing to the back of the eye
• Etiology
  • Failure of the embryonic primary vitreous and hyaloid vascular system to regress during gestation
• Clinical features
  • Leukocoria
  • Reduced visual acuity up to complete loss of vision
  • Microphthalmia of the affected eye
  • Usually unilateral
• Diagnostics
  • Slit-lamp examination
    • Anterior type
      • Lens changes (clouded membrane → membranous cataract)
      • Vascularized whitish retrolental tissue
      • Ciliary body villi are displaced towards the center and are visible in the pupil
    • Posterior type: Retinal detachment and retinal dysplasia are possible
  • Ultrasonography: if posterior eye segments cannot be assessed properly due to clouding of the lens
• Treatment
  • Symptomatic treatment
• Complications
  • Aqueous fluid drainage disorder → glaucoma
  • Retinal detachment
  • Vitreous hemorrhage

Infants with leukocoria should be examined for the presence of life- or sight-threatening conditions, such as retinoblastoma.

• Definition: deposits in the vitreous body perceived as spots or strings drifting through the visual field
• Epidemiology ^[4]
  • Peak age: > 50 years
  • ♀ = ♂
• Etiology ^[5]
  • Primary floaters: collagen fibrils originating from within the vitreous body
    • Weakened vitreoretinal adhesion → posterior vitreous detachment (most common cause)
    • Degenerative processes (e.g., liquefaction, aggregation of collagen fibrils) in the vitreous humor
    • Risk factors: myopia, Stickler syndrome, Marfan syndrome
  • Secondary floaters: protein, amyloid, or cell debris originating from outside the vitreous body
    • Retinal detachment, retinal tear
    • Vitreous hemorrhage
    • Posterior uveitis
    • Eye tumor (e.g., ocular melanoma)
    • Intraocular foreign body
• Clinical features
  • Perception of opacities of various shapes and sizes (e.g., spots, strings, filamentous structures)
    • Follow eye movements quickly
    • Drift slowly across the visual field when the eye is still
    • Tend to move away when gazed at directly
    • Appear more intensely against bright lighting and monochromatic areas (e.g., white paper, blue sky)
  • Symptoms indicating secondary floaters
    • Sudden increase in/occurrence of floaters, especially if accompanied by photopsia and/or vision loss
    • Showers of floaters: the sudden appearance of innumerable floaters (perceived as multiple black spots)
• Diagnostics
  • Ocular ultrasound: especially useful to rule out secondary floaters and quantify primary floaters
    • Visualization of the entire vitreous body
    • Assessment of the severity of floaters is possible by measuring vitreous opacities, which are non-sight-threatening but may cause visual disturbance and, subsequently, affect quality of life.
  • The diagnosis of the disease condition causing secondary floaters typically involves slit lamp examination or ophthalmoscopy.
• Treatment ^[5]
  • Patient education on symptoms indicating secondary floaters
  • Primary floaters
    • First line: observation and reassurance
    • Vitrectomy
    • Laser vitreolysis
  • Secondary floaters: treatment of underlying disease (discussed in respective articles)

A severe increase in floaters accompanied by photopsia is a typical symptom of acute posterior vitreous detachment, which bears a risk of retinal tearing and retinal detachment.

Showers of floaters indicate the presence of free cells in the vitreous and are usually associated with vitreous hemorrhage.

Synchysis scintillans (cholesterolosis bulbi)

• Definition: degenerative liquefaction of the vitreous body with cholesterol deposits
• Epidemiology: very rare, onset usually in mid-adulthood
• Etiology: can result from chronic vitreous hemorrhage
• Clinical features
  • Usually asymptomatic
  • Floaters
• Diagnostics
  • Slit lamp examination: white floaters in the posterior chamber of the eye (snow-globe effect)
• Treatment: not indicated; may become necessary if complications occur
• Complications: advanced liquefaction → collapse of the vitreous body (see vitreous detachment)

Asteroid hyalosis (synchysis nivea) ^[6]

• Definition: degenerative liquefaction of the vitreous body involving vitreous opacities due to deposits of fatty calcium salts
• Etiology
  • Unknown cause
  • Associated with diabetes mellitus, hypercholesterolemia
• Clinical features
  • Usually asymptomatic
  • Unilateral floaters or vision loss may occur
• Diagnostics
  • Opthalmoscopy/slit lamp examination: multiple, whitish, bright, and round opacities
• Treatment
  • Not indicated (since typically asymptomatic)
  • Vitrectomy if vision is significantly impaired