Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Visit 2 > 6.1.12 manage px sx rd > Flashcards

6.1.12 manage px sx rd Flashcards

1
Q

What does the vitreous look like in a normal young eye?

A

A homogenous solid gel that appears optically empty

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Where in the eye is the vitreous gel bag most tightly adhered to the retina?

A
  • ora serrata
  • blood vessels
  • optic disc
  • in myopic px, areas of lattice
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

How does the ora serrata relate to the vitreous bag?

A

boundary between retina and ciliary body- this is where the vitreous base is and it is anchored throughout life even after pvd even though rest of vitreous bag has shrunk into the centre of the eye

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Average age for PVD?

A

50-70 yrs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Which px are rd’s more likely?

A
  • myopes
  • trauma
  • after ocular surgery
  • ocular inflammation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is the relationship between PVD and rhegmatogenous rd (rrd)?

A

PVD begins- vitreous liquefaction/syneresis

  1. vitreous contracts separating from retina
  2. Any hole in the vitreous bag lets liquefied vitreous enter the space between the retina and contracting vitreous gel- this liquiefied vitreous causes vitreous gel to pull away further from the retina and sink inferiorly. Any weak attachment between the vitreous bag and retina then it will pull away completely.
  3. Photopsia sx may occur in areas where the vitreous is still attached to the retina as the tugging continues and pulls at the retina
  4. Collagen filaments/fibres left in the vitreous bag aggregate together and float in vitreous (floaters)

Retinal tear

  1. During vitreous collapse, a shearing force is exerted in areas where there is a strong adhesionto the retina which may cause a retinal tear and if it is over a blood vessel a vitreoous haemorrhage may occur
  2. Tears associated with a PVD are commonly superior, symptomatic and U-shaped. As the vitreous bag contracts, the bag pulls into the centre and drops inferiorly

Retinal detachment

  1. A rhegmatogenous retinal detachment (RRD) results from fluid entering the space between the RPE and neuro-sensory retina through a hole or tear (subretinal space)
  2. Most RRDs begin superiorly, usually superior temporally
  3. Due to gravitational forces, RRDs may progress quickly to involve the macula
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are the 3 types of RD?

A
  • Rhegmatogenous
  • Exudative
  • Tractional
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

How does an exudative rd occur?

A

Fluid from choroid gets into subretinal space through damaged RPE or blood-retinal barrier
- common causes include a sub-retinal neovascular membrane (AMD) or choroidal malignant melanoma

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

How does a tractional rd occur?

A

Sensory retina is pulled away by contracting proliferative membranes
e.g. new vessels in diabetic retinopathy grow out from the retina, into vitreous. They are usually very weak but form a scaffold and so if vitreous contracts or there is a shearing force again- it tuges on fine new vessels causing bleeding and can also lift off the retina . With eye movement or a PVD, blood vessels pulled towards centre of the eye taking retina with it

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is the risk of an rd in normal eyes compared to highly myopic eyes?

A

normal is 1 in 300

in highly myopic eyes (>6D) this increases to 1 in 20

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is the common timescale of RD after PVD?

A

Most RDs occur within 6 weeks of PVD

An RD after 3 months of PVD onset is rare

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What causes vitreous floaters?

A

Vitreous liquefication from vitreous syneresis where collagen aggregates in the contracting vitreous bag and floats around

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What do vitreous floaters look like?

A

Are entopic images of opacities most visible when seen against a uniform, bright background, they move on eye movement.
Awareness depends on:
-size
-optical density of the opacity
-distance from retinal surface
-pupil size
The closer an opacity to the retina, the larger the apparent shadow
Opacities are more noticeable with a dilated pupil

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What are the causes for floaters (and why) in order of most clinical concern to least?

A
  • Blood, pigment or inflammatory cells in the vitreous: from RD, posterior uveitis or vitreous haemorrhage
  • Vitreous floaters: age-related from vitreous liquefaction culminating in PVD
  • Asteroid Hyalosis: calcium soaps attached to collagen fibres- generally in older px and 90% cases unilateral
  • Debris in the tear film: move with eye blink more than vitreous floaters
  • Corpuscles in retinal blood vessels: tiny, rapidly moving specks visible when staring at a bright uniform surface
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What does photopsia look like?

A

Luminous flashes associated with PVD, tears or RRD usually have a vertical orientation and are exacerbated by rapid eye movement

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What are the causes of photopsia?

A

RD: rhegmatogenous, exudative, tractional

Acute PVD: Vitreous contraction associated with PVD pulls on retina causing stimulation of photoreceptors- once a PVD is complete (vitreous bag only attached at ora serrata) the traction on the retina is released and photopsia will cease

Migraine with visual aura: Definite pattern, associated headaches common, px past hx

Retinal disease: such as artery occlusion or multiple evanescent white-dot syndrome- look for associated retinal signs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

How may a px present with an RD?

A

60% of px with RD have sx of floaters with or without flashes.

The remainder of px with RD have no sx until a black shadow or curtain enters their field of vision

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What px Hx is important and why in those presenting with f+f?

A

Age: PVD is age-related occurring in <10% of people aged under 50yrs, but in >60% of people aged over 65yrs

Myopia: Myopes are 5x more likely to have retinal degenerations e.g. lattice, which pre-dispose to rd

Family hx or previous RD: Increased risk of RD if family Hx or RD in the fellow eye

Systemic disease: Proliferative diabetic retinopathy can cause tractional retinal detachments

Hx of ocular trauma, surgery or inflammation: cataract operations increase risk of RRD. 50% of RRDs occur within 1 year of cataract operation. Inflammation can cause premature PVD

Loss or distortion of vision: (usually a late sx) Px describe curtains, shadows, veils across vision- suggests RD or vitreous haemorrhage. Metamorphopsia may be reported

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

How do you investigate sx of floaters and how concerning are the answers?

A
  • Are floaters of recent onset or always been there? If stable less concerning than recent or changing
  • What do they look like? Vitreous degeneration with or without a corresponding RD usually described as a few small dots, lines, twigs, hairs or cobwebs. Vitreous floaters move on eye movement
  • How many floaters are there? Too many to count and/or sudden shower/cloud is ominous: Suggests blood/pigment cells present due to tear or RD NB: look for signs
  • Which eye do you see them in? Localisation usually helpful to differentiate which eye affected -RD essentially unilateral
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

How do you investigate sx of flashes and how concerning are the answers?

A
  • Describe the flashes? Vertical streaks of lightening or fireworks typical of PVD alone or with tears and/or RD. Flashes on their own are not common in PVD/RRD- usually in conjunction with floaters. Floaters only, or combined with flashes, are most common sx of PVD or associated/tears/RRD. Eye localisation for flashes is not generally helpful
  • When do you notice them? PVD/RD usually at night or dim illumination. Migraine is at any time
  • How long do they last? PVD/RD- very short duration. Seconds although can occur many times. Migraine -lasting longer and definitive course.
21
Q

What are signs of PVD?

A
  • Detached posterior vitreous surface can sometimes be seen and traced to the only place of retinal attachment left: the vitreous base at the ora serrata
  • A Weiss’ ring floater is seen in PVDs (detached glial tissue from edge of optic disc as vitreous contracted)- it looks like a feint, rust coloured ring against the backdrop of the retina
22
Q

What is the risk of breaks and RRD with degeneration and myopia and why?

A

60% of breaks occur in areas with pre-disposing retinal degeneration, <1% of px with retinal degeneration actually develop an RRD

The highest risk of developing rd is lattice degeneration and high myopia

Strong vitreo-retinal adhesions present in lattice cause tears when vitreous shrinks during PVD. Liquefied vitreous seeps through retinal holes into sub-retinal space causing slow RD. Holes occur more frequently in areas of degeneration. U-shaped retinal tears may develop at the edge of the areas of lattice

23
Q

What does lattice retinal degeneration look like and sx?

A

Oval or linear patches of atrophied retina/areas of retinal thinning with reddish crater-like base. Occassionally criss crossing fine white lines are seen- present in 10% of lesions and may represent hyalinised blood vessels (blood vessel thin and may become white as pass through the areas of lattice. intead of RPE pigmentation.
Asymptomatic and often seen in myopes
A variant of lattice is called snailtrack- it has yellow-white surface flecks and looks like snail slime

24
Q

Where is lattice retinal degeneration?

A

Frequently temporally at mid-point between ora serrata and equator.
Usually bilateral.
Occassionally retinal holes present

25
Q

How to manage a px with lattice retinal degeneration?

A

In most px it does not cause tears or rd, so they should be advised about sx of rd, but do not need referral unless a tear is present or rd has occurred in the other eye.

Prophylactic treatment of lattice is not done unless tear is present or rrd has occurred in fellow eye

26
Q

What does a new retinal tear look like?

A
  • A different colour (darker orange/red) compared to surrounding retina- difficult to see in a pale retina
  • Most common is U-shaped or horseshoe tear
  • Usually superior temporally
27
Q

What does a giant retinal tear look like and what is it most commonly caused by?

A

Begin near ora serrata and progress centrally

often associated with blunt trauma

28
Q

What are the signs for retinal tears?

A

15-30% of px with symptomatic pvd have retinal holes.
Thinning of the retina may lead to round or oval retinal hole- a large hole has a greater risk of RRD.
Holes may be seen in areas of lattice/snailtrack. Small round atrophic holes present little risk of a RRD, in young px, retinal holes in areas of lattice occassionally cause asymptomatic, slow RRD

29
Q

How to manage a px with a retinal tear or hole?

A

If the px is asymptomatic then an rd may not happen but an urgent-same day referral is still required

30
Q

What are the signs in the vitreous of an rd or tear and management?

A

Shafer’s sign- pigment cells ‘tobacco dust’ in anterior vitreous
If a small retinal blood vessel has been ruptured during RD, red blood cells may also be present in the vitreous.

This is highly suggestive of a retinal break or rd so same day urgent referral is indicated

31
Q

How to check for Shafer’s sign?

A

On a px with dilated pupils use a slit lamp focussed on anterior vitreous just behind lens
Bright illumination and high mag, ask px to look up down (left and right if you want) and then straight ahead and note any small brown speckles in beam

32
Q

What does an RD look like?

A

A fresh RD has a convex, slightly opaque appearance.
It can look corrugated with opaque greyish folds.
Blood vessels look darker within the RD and the colour difference between retinal veins and arteries is lost.
The RD undulated with eye movement

33
Q

What does an old RD look like?

A

Old RDs that have not fully detached may have pigmented borders or white lines between attached and detached areas of the retina.
Retinal thinning often occurs after rd
Eyes with old RDs may have cysts within the RD
Old RDs that have naturally reattached themselves are typically inferior as the effect of gravity means the retina is put back in place without treatment

34
Q

What do field results look like with rd?

A

Relative scotoma in rd

The vf field defect is related to retinal detachment location

35
Q

How does an RD affect AC?

A

sometimes RD cause mild uveitis type-reaction with resulting keratic precipitates

36
Q

How may an RD effect pupils?

A

large RDs cause an RAPD

37
Q

How may an RD affect VA?

A

VA is much reduced if macula had detached

38
Q

How may an RD effect IOP?

A

IOP in affected eye may be reduced by as much as 5mmHg due to cilliary body shutting down

39
Q

How to manage a px with suspect RD or RD?

A

Urgent same day referral
Superior retinal detachment progress quicker than inferior rd due to gravitational forces.
Longstanding RD, particularly if macula is detached and VA is reduced is less of an emergency but will still need urgent referral

40
Q

How do you do an eye examination of a px with sx of rd?

A

Dilate the pupil and do slit lamp biomicroscopy of the anterior and posterior segments noting:

  • presence of vitreous changes
  • pigment cells in anterior vitreous- Shafer’s sign
  • Vitreous haemorrhage or red blood cells
  • Cells in anterior chamber

Fundus exam- Superfield or superVitreo optimal, noting:

  • Status of peripheral retina- tears/holes/detachments/lattice degeneration
  • Presence of vitreous syneresis or PVD

Swinging light test to check for RAPD.
Contact tonometry-IOP
Visual Acuity
Visual field examination

41
Q

How to differentiate between migraine aura and photopsia due to other causes?

A
  • More common in females than males
  • Usually <40 yrs on 1st presentation
  • Family hx of migraine is common
  • Trigger factors e.g. stress, change in sleep pattern, visual stress, food including: red wine, cheese, caffeine, chocolate, MSG
  • Aura typically last approx 15-40mins and has definitive course before subsiding to be replaced by throbbing headache (front of the head or sides of the head)
42
Q

What is retinoschisis?

A

Aquired retinoschisis is a subtle splitting of the outer retina into 2 layers (2 retinas). It is common, occurring in up to 20% of px. 70% of px with retinoschisis are hypermetropes.

43
Q

Where does retinoschisis occur in the eye compared to RD?

A

Usually in the temporal retina, often inferiorly.
Usually between the outer plexiform and outer nuclear layer.
Rarely between the inner plexiform and inner nuclear layer

RD is usually superior and occurs between the RPE and rest of retina

44
Q

What does retinoschesis look like?

A

Smooth, convex, elevated surface that does not undulate with eye movements. Thin, occluded blood vessels may be present and they often appear white.

Yellow- white flecks common on inner surface of inner layer and have the appearance of snowflakes

Holes may be present but because there is no communication to subretinal space they generally do not result in RD

No pigment or uveitic response is seen because the RPE is unaffected

45
Q

How to manage retinoschisis?

A

It is normally non-progressive, asymptomatic and benign. Rarely will it involve a large area, causing symptomatic absolute vf loss
So:
-If no sx and confident diagnosis- referral not needed
- If a px has sx of f+f, or you are unsure referral is advised to check

46
Q

What sx and signs warrant an urgent same day referral (daylight hrs)?

A

Sx:

  • Sudden increase in floaters
  • Persistent cloud, curtain or veil over the vision

Signs:

  • RD with good vision
  • Vitreous or pre-retinal haemorrhage
  • Shafer’s sign
  • Retinal tear/hole
47
Q

What sx or signs warrant an urgent referral with a next available appt (not necessarily same day)?

A
  • RD with poor vision (macula off)

- Lattice degeneration with sx of recent f+f but without hole or tear

48
Q

What sx or signs warrant a discharge with SOS advice?

A
  • Manage in practice with verbal and written advice
  • Uncomplicated PVD (without sx)
  • Lattice degeneration without sx
  • Retinoschisis- if no sx and sure of diagnosis

Visit 2 (11 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions