1 - Vitreous

75%

The vitreous makes up _______% of the ocular volume in the vitreous chamber.

water

What makes up 99% of the vitreous contents?

collagen, mostly type 2 = fibrils are mostly bound in a gel structure

GAGs = hyaluronic acid and chondroitin sulfate

cells

inorganic salts

small organic molecules

soluble proteins albumin and globulin

Aside from water, what other things make up the vitreous?

transparency

spacing between fibrils

What are the 2 main functions of the GAG hyaluronic acid?

spacing between fibrils

NOTE: lower [ ] than hyaluronic acid

What is the main function of the GAG chondroitin sulfate?

hyaluronic acid and vitrosin

What 2 things create an elastic property in the vitreous?

anterior to posterior, being densest around the edges

Explain the pattern that the collagen fibrils run in the vitreous

STRONG

vitreous base near ora

Wieger's ligament on posterior lens (forms Egger's line)

ONH

macula

retinal BV

WEAK

Rank the adhesion locations of the vitreous cortex from strongest to weakest.

area between the attachments at Wieger's ligament

What forms Berger's space

condensation of collagen fibrils

What causes floaters in the vitreous?

hyaluronic acid depolymerizes = breaks down the gel = vitreous liquefaction, fibril condensation, lacunae (liquid pockets) form

What causes synchysis senilis in the vitreous?

shrinkage of vitreous as solids and liquids separate

What causes syneresis in the vitreous?

before age 50 = 25% liquid
after age 60 = 62% liquid

How does the % liquid content of the vitreous change before age 50 vs after age 60?

lacunae of liquified vitreous

What aging change in the vitreous is shown by the stars in this image?

posterior vitreous detachment

What condition is shown here?

hyaloid membrane separates from retina at the area posterior to the vitreous base

What is a PVD?

>45 years old

women

What are the demographics of who is most affected by PVD?

age = vitreous liquifaction, lacunae form, fibrin contraction

high myopia

trauma

inflam

aphakia

CAT surgery

vitreoretinal degeneration = thinning and splitting of hyaloid memb = vitreous fluid enters posterior space between retina and vitreous

What are some causes of PVD?

complete PVD w/ collapse of vitreous gel = Weiss ring detached from ONH

What type of PVD is shown here?

incomplete PVD w/ collapse of vitreous gel = ONH attachment still intact

What type of PVD is shown here?

perifoveal PVD = adhesion at macula, VMT

What is shown in stage 1 PVD here?

macular PVD, still attached everywhere else

What is shown in stage 2 PVD here?

near complete PVD, still attached at ONH

What is shown in stage 3 PVD here?

complete PVD with ONH detached

What is shown in stage 4 PVD here?

Weiss ring after a complete PVD (may collapse over time and not be this distinct)

What is shown here?

visible vitrous cortex hanging from the vitreous base

macular traction if incomplete PVD

tobacco dust/Shafer sign = pigmented cells floating in vitreous

Aside from a Weiss ring, what are some other signs of PVD?

liquefied vitreous accesses retina-RPE interface = breakdown mucopolysaccharide bond (glue of RPE) = pigment cells enter vitreous, are mobile

What causes tobacco dust/Shafer sign?

52x more likely to have an active or impending RD/break in retina

What does tobacco dust/Shafer sign mean?

visible vitrous cortex hanging from the vitreous base

What sign of PVD is seen here?

Weiss ring = complete PVD

What sign of PVD is seen here?

incomplete PVD bc still attached at ONH

Is this PVD complete or incomplete?

incomplete PVD bc still partially attached = tugs on retina

Is this PVD complete or incomplete?

floaters esp sudden onset

flashes/photopsias due to vitreoretinal traction

metamorphopsia or slightly reduced VA due to vitreoretinal traction

What are some symptoms of PVD?

macular traction, edema, hole

vitreous hemorrhage = also likely to occur with retinal break

retinal break/RD

retinal hemorrhage

What are 4 potential complications of a PVD?

DFE with scleral depression

3M gonio

B-scan ultrasound if cloudy media

What are some alternative ways to evaluate a PVD?

educate on S/S of RD

educate on likelihood of RD within 1 year

follow up as needed

What is the management for a PVD?

2-4 weeks

2-3 mos

6 mos

What is the follow-up schedule for a PVD if there is no retinal break or hemes?

1 week

2-4 weeks

3 mos

6 mos

What is the follow-up schedule for a PVD if there is no retinal break but there are mild VH or peripheral dot hemes?

next day by retina specialist bc of the high likelihood of retinal break

What is the follow-up schedule for a PVD if there is no retinal break but there are significant VH or pigmented vitreous cells present?

systemic CT disease resulting in skeletal abnormalities, aortic dissection, cardiac abnormalities

What is Marfan syndrome?

sup-temporal lens luxation = often good VA if visual axis not involved

axial myopia

vitreous degeneration

decreased corneal diameter

iris transillumination

RD

vitreous loss during CAT Sx

What are some ocular findings of Marfan syndrome?

systemic CT disease resulting in tissue fragility, increased skin elasticity, hypermobile joints, risk under general anesthesia

What is Ehlers Danlos?

high myopia

microcornea

glaucoma

angiod streaks

vitreoretinal degeneration w/ lattice common

RD

ptosis

strabismus

What are some ocular findings of Ehlers Danlos?

elevated plasma and urinary homocystine = skeletal and cardiovascular abnormalities, thrombotic vasc occlusions, high risk under anasthesia

What is homocystinuria?

inferior lens luxation

vitreoretinal degeneration and detachment

What are some ocular manifestations of homocystinuria?

trauma or lens dislocation (rare) = anterior hyaloid membrane detaches and hangs in front of pupil

What causes anterior vitreous detachment?

retinal evaluation due to highly increased risk for retinal tears, dialysis, breaks

then 1 year f/u

What is the management for anterior vitreous detachment?

small yellow-white spheres of Ca, P, O, lipids that are suspended throughout collagen fibrils of vitreous

What is asteroid hyalosis?

unilateral

Is asteroid hyalosis usually unilateral or bilateral?

idiopathic most likely

What causes asteroid hyalosis?

no = typically asymptomatic, though pt MAY complain of floaters

Does asteroid hyalosis typically affect vision?

these are adherent to the vitreous framework, so they stay suspended with ocular movement

How can we differentiate asteroid hyalosis from synchisis scintillans, a similar DDx?

pt education

pars plana vitrectomy in extreme cases where VA is affected

What is the management for asteroid hyalosis?

rare degenerative ocular condition characterized by the accumulation of cholesterol crystals in the vitreous

What is synchysis scintillans?

severely diseased or blind eyes

What causes synchysis scintillans?

these are NOT attached to the vitreous framework, so they settle after ocular movement like a snow globe effect

How can we differentiate synchysis scintillans from asteroid hyalosis, a similar DDx?

crystals can into AC = pseudohypopyon

What is a possible complication of synchysis scintillans?

hyaloid artery (2 and 3 in diagrim) in primary vitreous does NOT undergo normal involution by macrophage-mediated apoptosis

What is persistent fetal vasculature (PFV)?

anterior form >>> posterior form or combo

Which forms of PFV tend to have better outcomes?

unilateral

Is PFV usually unilateral or bilateral?

non-heritable

can be associated with AD (NDP gene) or AR (ATOH7 gene) inheritance

Is PFV usually heritable or non-heritable?

anterior PFV, severe form

What form of PFV is seen here?

leukocoria

microphalmia

CATs

elongated or drawn in CB processes

shallow AC when eye is small = glaucoma

retrolental fibrovasc membranes = cause traction on peripheral retina

intralenticular hemorrhages bc BV still acive

dilated iris BV

strabismus bc of reduced VA

ectropian uvea

iris coloboma

What are some signs and complications of anterior PFV?

persistent pupillary membrane (PPM) = remnant of anterior tunica vasculosa lentis on iris/lens = usually benign, no effect on VA

What form of anterior PFV is seen here?

epicapsular stars = remnant of anterior tunica vasculosa lentis on anterior lens

What form of anterior PFV is seen here?

Mittendorf dot = attachment of anterior hyaloid artery on posterior lens

What form of anterior PFV is seen here?

leukocoria

microphalmia

retinal folds = tractional RD of the posterior pole

hypoplastic/dyplastic ONH

vitreous memb/stalk = hazy fibrotic stalk with peripapillary macular traction and fluid

strabismus bc of reduced VA

macular pigment disruption or hypoplastic macula

clear lens!

What are some signs and complications of posterior PFV?

vitreous stalk may have active vasc and traction = RD

How can posterior PFV be vision threatening?

Bergmeister's papillae = benign remant of sheath around hyaloid artery at ONH

What form of posterior PFV is seen here?

remnant of hyaloid artery

What form of posterior PFV is seen here?

combination ant + post form with stalk

What form of PFV is seen here?

observe if benign

R/O ddx like retinoblastoma, ROP

surgical intervention like lensectomy or vitrectomy if...

visual axis occluded = amblyopia

retinal traction = RD or break

shallow AC = angle closure glaucoma

How do we manage PFV?