Disorders of the Vitreous and Peripheral Retina Flashcards
What the four major points of attachment of the vitreous? Order them from strongest to weakest. What determines the strength of the attachment?
Strongest –> Weakest:
- Vitreous Base
- Optic Nerve Head
- Retinal Vasculature
- Macula
The vitreoretinal adhesion is strongest where the ILM of the retina is the thinnest
What happens to the vitreous as we age?
The vitreous body is comprised of a gel matrix that begins to liquefy and derange as we age (40+). The liquefied vitreous coalesces into pockets called lacunae. Eventually, the adhesion of the vitreous to the posterior pole weakens and liquid accumulates in the retro-cortical space. This accumulation leads to a collapse of the vitreous body and eventually leads to a PVD.
What group of people experience a change in the vitreous sooner? Myopes or hyperopes?
Myopes
What is a PVD? What group(s) is/are more likely to have a PVD?
A PVD: Posterior Vitreous Detachment occurs when the vitreous liquefies and fluid accumulates behind the vitreous cortex and in front of the retina. This pushes the retina and vitreous apart and eventually, the force is great enough to displace the vitreous from the retina.
PVD’s occur in 85% of aphakic patients and is more common in women than men.
What are the different kinds of PVD?
Complete PVD: When the vitreous is completely separated from the ONH
With collapse: When the vitreous begins to collapse due to lacunae coalescing and gravity.
Complete PVD with collapse
Incomplete PVD with collapse
Complete PVD without collapse
How do PVD with collapse and PVD without collapse differ?
PVD with collapse occurs in older patients, especially myopes. PVD with collapse includes degeneration and lacunae in the vitreous. PVD with collapse has a rapid onset and also is accompanied by hemorrhages and retinal breaks in 8-15% of cases.
PVD without collapse occurs in younger patients and there are no vitreous changes. Retinal breaks and hemorrhages are rare and the onset is a more gradual, slow event.
Why is an anterior vitreous detachment rare?
Because the vitreous base is the strongest point of attachment between the vitreous and the retina.
If you see a vitreal hemorrhage accompanying a PVD, what may also be present?
You are worried about a retinal break being present. Retinal breaks are associated with a PVD + Vitreal hemorrhage 75% of the time!
What are free RPE cells in the anterior vitreous a sign of?
Anterior vitreous detachment
Retinal detachment
Explain asteroid bodies
Asteroid bodies are yellow-white granules that consist of calcium soaps that accumulate in the vitreous body. These bodies make it very difficult for us to get a look at the retina, but these patients will have perfectly normal visual acuity and quality of vision. 90% are unilateral.
What is PHPV?
PHPV: Persistent Hyperplastic Primary Vitreous. PHPV is a failure of regression of the structures of the primary vitreous during development. There are anterior and posterior forms of PHPV.
Anterior: Unilateral with leukocoria. DDx: Retinoblastoma
Posterior: DDx: Retinopathy of prematurity (ROP is when a newborn is exposed to 100% oxygen)
What are the 4 locations of retinal anomalies?
- Oral Zone: Ora Serrata
- Intrabasal Zone: Within the vitreous base
- Juxtabasal Zone: Along the posterior border of the vitreous base
- Extrabasal Zone: Posterior to the vitreous base
Define Retinal Detachment.
Separation of the RPE from the neurosensory retina.
What are the three types of retinal detachment? Which type(s) of retinal detachment is/are bullous? Which is most common?
- Rhegmatogenous Retinal Detachment: bullous (most common)
- Tractional Retinal Detachment: Not bullous
- Exudative Retinal Detachment: Not bullous
Which type of retinal detachment (Rhegmatogenous/Tractional/Exudative) is not usually found in the peripheral retina?
Tractional
Explain a Rhegmatogenous Retinal Detachment.
A Rhegmatogenous Retinal Detachment (RRD) is the most common form of retinal detachment. RRD is a retinal emergency and there is a high probability of vision loss. The combination of peripheral breaks (NOT holes) in the retina and vitreous adhesion allows fluid to accumulate in the subretinal space (between PR and RPE). The fluid accumulation gives retina a bullous appearance and the area of the retina that is affected appears convex. Patients will report flashes of light/floaters in their vision and you may see RPE in the anterior vitreous. Once the RRD occurs, RPE hyperplasia will also occur. In an RRD that is ~3 months or older, there will be a demarcation line of pigment surrounding the detachment. If there is no demarcation line, either the RRD is less than 3 months old, or the detachment is superior and is likely still progressing.
What are some clinical features of an RRD? (4)
Opaque retina: PR die once they separate from the RPE, becoming opaque
Pigment in anterior vitreous
PVD
Linear Retinal Tear
What procedure is typically done to treat an RRD?
Scleral buckle reattachment
What are 2-3 initial (2-4 months) and late post-op complications of fixing an RRD?
Initial:
Re-detachment
Glaucoma
Late:
Ptosis
Cataract
Both:
Cystoid macular edema
Preretinal macular fibrosis
What color are retinal holes/tears? Why?
Retinal holes/tears are always red. There are fewer layers of the retina that attenuate the color of the RPE.
Which way does the apex of a horseshoe tear typically point?
Towards the posterior pole.
What is the most common retinal break?
Atrophic retinal hole
What is the difference between an atrophic retinal hole and an operculated retinal hole?
An atrophic retinal hole will not have a chunk of tissue floating above it while an operculated retinal hole will (tissue floating is called an operculum)
What region of the retina does an operculated hole usually occur?
Between the ora and the equator
What is the most significant disorder of the retina that predisposes someone to retinal breaks/RDD?
Lattice degeneration
Where is lattice degeneration usually found?
Inferior/superior retina
Where are you most likely to see a vitreoretinal traction tuft?
Nasally
What kind of retinal anomaly has a characteristic “fishbone” appearance?
Lattice Degeneration
How does Snail-Track Degeneration differ from lattice Degeneration?
Snail-Track does NOT have the fishbone appearance that Lattice does.
How do you manage an RRD?
Scleral buckle
How do you manage a retinal tear?
Treat with laser/cryopexy if they have a history of detachment or a subclinical detachment of 1DD+. Otherwise, just monitor
How do you manage an atrophic retinal hole?
Referal if symptomatic with holes, or with a subclinical detachment of 1DD+
How do you manage an operculated hole?
If symptomatic with holes or with a subclinical detachment of 1DD+, if you see vitreoretinal adhesion, or if they are aphakic you should refer for a consult, otherwise monitor
How do you manage a vitreoretinal tuft?
Patient ed on signs/symptoms of RD and refer if you see a retinal break with a traction tuft
How do you manage lattice degeneration?
Education on signs/symptoms of RD and refer if you see breaks at the margin of the lattice or if the patient is symptomatic with atrophic holes
How do you manage snail track degeneration?
Education on signs/symptoms of RD and refer if you see breaks at the margin of the lattice or if the patient is symptomatic with atrophic holes
What is acquired retinoschisis? How does it differ from a retinal detachment?
The retina is splitting at the OPL or INL (Usually OPL). This split fills with fluid and will lead to an absolute visual field defect. Splitting at the OPL/INL prevents synapses from PR to be sent to the nerve. This differs from a retinal detachment because the neurosensory retina is still intact, the PR are just slowly dying, resulting in a relative visual field defect. Retinoschisis also will be transparent and will rarely present with a tear while a RD will have opaque sections of the retina and will have the tear.
Why does Retinoschisis not have a demarcation line like a retinal detachment?
Retinoschisis has a split in the retina at the OPL/INL, so the RPE is not exposed, and there will be no RPE hyperplasia.
How do you manage a retinoschisis patient?
It varies based on the layer where the break occurs. If the break occurs in the inner layers only you can monitor it. If the break involves the outer layers or both the inner and outer layers of the retina, you should refer for consult.
What retinal anomalies have a high probability of vision loss? Which retinal anomalies have a moderate probability of vision loss? Which retinal anomalies have a low risk of vision loss?
High Risk:
RRD
Retinal Tear
Moderate Risk: Operculated Hole Atrophic Hole Lattice Snail-Track Vitreoretinal Traction Tuft Acquired Retinoschisis
Low Risk: Focal Chorioretinal Atrophy Congenital RPE Hypertropy RPE Hyperplasia Choroidal Nevus White Without Pressure
