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OD3 (S1&2) > DIS - Diseases of the Vitreous Humour I - Week 8 > Flashcards

DIS - Diseases of the Vitreous Humour I - Week 8 Flashcards

1
Q

Describe the vitreous humour (2).

A

A clear avascular and acellular gel

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2
Q

What is the typical volume of the vitreous humour and what percent of it is water?

A

~4mL
99% H2O

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3
Q

Describe the structure of the vitreous humour. What kind of strength is conferred with this structure?

A

Complex parallel structure of collagen fibres
Confers antero-posterior strength

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4
Q

What are collagen fibres in the vitreous humour separated by and what is the significance of this?

A

Fibres separated by hyaluronic acid pockets, which contain water

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5
Q

What is the main collagen matrix of the vitreous humour held in place by? What does this improve?

A

It is cross-linked by type 2 collagen
Improves lateral structure and strength

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6
Q

What does the collagen matric of the vitreous humour provide a frame for? What does this act as and what does it attract? What is the outcome (2)?

A

Provides a frame for hyaluronic acid coils to anchor to
Coils act as a spring
Coils attract and bind water
-results in the formation of a gel to cushion the eye

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7
Q

While the vitreous humour is relatively acellular, list 6 cells you could expect to find here.

A

Hyalocytes
RPE cells (fibroblasts)
Myo-fibroblasts
Astrocytes
Macrophages
White blood cells

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8
Q

What is the vitreous humour surrounded by (aside from the retina) and what is it exactly? What is this fused with?

A

By a hyaloid membrane
-condensation of collagen IV fibres
-fused with the retinal internal limiting membrane

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9
Q

Where are the strongest adhesions of the hyaloid membrane to the eye (4)? List in order starting with strongest.

A

Pars plana
ONH
Foveola
Retina (BV and other)

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10
Q

Where is the vitreous base and how long is it?

A

3 to 4mm zone straddling pars plana and ora serrata

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11
Q

List 6 functions of the vitreous humour.

A

Maintains eye shape and structural support
Sustains retinal apposition
Promotes optical clarity
Provides shock absorption
Prohibits migration of cells/blood
Inhibits neovascularisation

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12
Q

What compound of the vitreous humour inhibits neovascularisation?

A

Opticin

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13
Q

What is the tunica vasculosa lentis, what does it do, and when does it form?

A

A vascular sheath to the lens, supporting active lens growth
Forms 1 month in utero

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14
Q

Where can the hyaloid artery be found and within what structure?

A

In cloquet’s canal within the tunica vasculosa lentis

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15
Q

Describe how the tunica vasculosa lentis forms and degenerates and when.

A

As the hyaloid system atrophies near term, a secondary vitreous humour forms near the retina, surrounding and compressing the primary vitreous humour into the TVL, extending from the ONH to the lens
It degenerates with time by 1 month post-natal

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16
Q

What are congenital abnormalities of the vitreous humour mostly due to?

A

Partial decay or remnants of the tunica vasculosa lentis

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17
Q

List the three most commn tunica vasculosa lentis remnants and where they are found.

A

Mittendorf dot (lens)
Bergmeister’s papilla (ONH)
Perisistent primary hyperplasic vitreous humour

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18
Q

Describe perisistent primary hyperplasic vitreous humour and what it encroaches on.

A

Thickened due to compression by secondary vitreous humour formation
Encroaches on the lens

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19
Q

What is a mittendorf dot? Use the SOAP acronym.

A

Anterior remnant of the hyaloid artery
S - patients usually asymptomatic
O - opacity and condesation just below and nasal to the posterior pole
A - advise patient and build confidence
P - none required

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20
Q

What slit lamp technique is best for mittendorf dots?

A

Best seen with red reflex, direct view for location

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21
Q

What is bergmeister’s papilla? Use the SOAP acronym.

A

Posterior remnant of the hyaloid artery
S - asymptomatic
O - remnant of the hyaloid system
A - DFE, look for traction
P - advise patient

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22
Q

How does bergmeister’s papilla look compared with a persistent hyaloid artery?

A

BP - solid mass of whitish tissue or delicate glial strands stretching over the disc
PHA - glia emanating from ONH towards lens

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23
Q

What is persistent hyperplasic primary vitreous humour? Is it anterior or posterior? Is it serious or benign?

A

When the tunica vasculosa lentis persists and proliferates
Anterior (mostly) or posterior (rare)
-potentially very serious

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24
Q

What are the signs of anterior persistent hyperplasic primary vitreous humour (3)?

A

Visual obstruction (amblyopia and strabismus)
Leukocoria (white pupil)
Fibrovascular proliferation behind the lens

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25
Q

List three possible diseases secondary to anterior persistent hyperplasic primary vitreous humour.

A

Lens swelling/cataract
2° glaucoma
2° retinal detachment

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26
Q

What is posterior persistent hyperplasic primary vitreous humour often associated with (3)?

A

Retinopathy of prematurity
Signs of retinal detachment
Posterior uveitis/inflammation

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27
Q

List four objective signs of posterior persistent hyperplasic primary vitreous humour.

A

Fibrovascular proliferation on the disc/retina
Traction on the retina/ONH from shrinkage (twisted disc appearance)
Lens opacity
2° retinal detachment

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28
Q

List four differential diagnoses for persistent hyperplasic primary vitreous humour.

A

Retinoblastoma
Retinopathy of prematurity
Cataract
Glaucoma

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29
Q

What is the management for persistent hyperplasic primary vitreous humour (4)?

A

Refer to an ophthalmologist
Provision of aphakic Rx
Manage amblyopia/BV
Note milder cases in adults - monitor traction for RD

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30
Q

What is a vitreous cyst (2)?

A

Uncommon remnant of the hyaloid system or overgrowth of CB epithelium

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31
Q

List two signs of a vitreous cyst.

A

Persistent floater
Visual disturbance

32
Q

How does a vitrous cyst appear?

A

Vague spherical mass in the vitreous humour

33
Q

List three differential diagnoses for vitreous cyst.

A

PVD
Cells due to uveitis
Traction

34
Q

What is the management for vitreous cyst (3)?

A

Monitor symptoms
-refer for vitrectomy or photocystotomy if problematic

35
Q

What is syneresis?

A

Age-related liquefaction of the vitreous humour

36
Q

Does syneresis occur sooner or later in myopes?

A

Sooner

37
Q

Describe how syneresis occurs .

A

Involves the release of previously bound water which accumulates in lakes
This is accompanied by a collapse of the gel structure and condensation of collagen into clumps or threads
Lakes coalesce eventually

38
Q

What gives most traction on the superior retina and where?

A

PVD at the blood vessels

39
Q

What are lacunae?

A

Lkes of accumulated water with syneresis

40
Q

What are three signs of syneresis?

A

Floaters from collagen condensations/water release
Posterior vitreous detachment
Traction/retinal detachment (flashes)

41
Q

How does syneresis appear on slit lamp examination (2)?

A

Floaters appear as ghost veils
Liquefaction (things swimming around)

42
Q

What is the best method to assess syneresis?

A

OCT for PVD

43
Q

What is the management for syneresis?

A

Advise and monitor

44
Q

What are vitreous floaters?

A

Any object in the vitreous humour seen by the patient

45
Q

When are vitreous floaters often seen?

A

Lying back and looking up into the sky

46
Q

What are operculum?

A

Floater due to retinal tissue

47
Q

List 7 things that can be a floater.

A

Cells
Vitreous strands
Retinal tissue
Foreign bodies
Calcium phosphate
Cholesterol
Amyloid

48
Q

What are four important signs/symptoms (history) that should be looked for if a patient presents with floaters?

A

Photopsia
Distortion
Trauma
GH issues

49
Q

List four differential diagnoses for vitreous floaters.

A

PVD
Retinal detachment/tears
Haemorrhage asteroid hyalosis
Synchisis scintillans

50
Q

Define posterior vitreous detachment.

A

Separation of the cortical vitreous from the ILM

51
Q

Is posterior vitreous detachment more or less common in women vs men?

A

More common in women

52
Q

Do lacunae form superiorly or inferiorly with syneresis and why is this so?

A

Usually superior due to gravity

53
Q

What are two patient signs of posterior vitreous detachment?

A

A large central floater (ring shape)
Photospia

54
Q

What are three things that may be found on a fundus exam for posterior vitreous detachment?

A

Peri-papillary large oval or partly oval floater - overlies disc
Hyaloid face well forward of the retina
Small pre-retinal or vitreal haemorrhage
-possible white retina due to traction

55
Q

How should psoterior vitreous detachment be worked up during history and what three additional conditions should be considered?

A

Comprehensive history on recent floaters and photopsia
Consider GH (diabetes), eye trauma, and inflammatory conditions

56
Q

What should you look ofr on a slit lamp exam of posterior vitreous detachment?

A

Vitreous face

57
Q

What should you do in the absence of a floater in a case of suspected posterior vitreous detachment?

A

OCT

58
Q

What four things can photopsia from posterior vitreous detachment indicate?

A

Retinal tear
RD from secondary retinal hole
Macular hole
Retinal or vitreous haemorrhage

59
Q

What is the management for posterior vitreous detachment? Include review schedule.

A

Educate patient to return if worse
Follow up after 2/12

60
Q

When should posterior vitreous detachment be referred (4)?

A

If it is recent and has resulted in
-visible retinal tears/tobacco dust
-persistent unexplained photopsia
-vitreous haemorrhage

61
Q

Does photopsia with posterior vitreous detachment tend to subside over time or get worse?

A

Will eventually subside

62
Q

What is asteroid hyalosis?

A

Lipids ebedded in a calcium phosphate matrix attached to the collagen framework

63
Q

How does asteroid hyalosis appear?

A

Yellow/white specks that move with the framework but come back to the original position (sway)

64
Q

True or false
Asteroid hyalosis is never found in eyes with posterior vitreous detachment

A

True

65
Q

Is asteroid hyalosis common more in young or older patients?

A

Older

66
Q

Is asteroid hyalosis typically uni- or bilateral? Are patients symptomatic?

A

Often unilateral and asymptomatic

67
Q

List four conditions which have a suggested association with asteroid hyalosis.

A

Diabetes/glucose intolerance
Hypertnesion
Atherosclerosis
Hyperopia

68
Q

Does asteroid hyalosis have any effect on vision?

A

Minor to none

69
Q

What is the treatment for asteroid hyalosis?

A

None

70
Q

What should be done if a patient have GH issues in addition to asteroid hyalosis?

A

Refer to GP for a workup

71
Q

True or false
Synchisis scintillans is never found in eyes with posterior vitreous detachment

A

False
It is only found in eyes with posterior vitreous detachment

72
Q

What is synchisis scintillans?

A

Cholesterol crystals that form in a liquid vitreous humour

73
Q

When does synchisis scintillans appear in the vision and what happens after and why?

A

Appears with eye movement and sinks due to gravity

74
Q

Is synchisis scintillans typically uni- or bilateral?

A

Bilateral

75
Q

When does synchisis scintillans tend to occur?

A

In younger patients after PVD

76
Q

What three conditions is synchisis scintillans associated with?

A

Advanced eye disease
Chronic vitreous haemorrhage
Trauma

77
Q

What is the management for synchisis scintillans?

A

None, but monitor underlying eye condition and possible glaucoma

OD3 (S1&2) (114 decks)

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