Week 1.10 Retinal Detachment Flashcards
(29 cards)
Vitreous
• 4/5ths of the eyeball
• ~4ml volume
• Transparent gel – 98% water
• Network of fine collagen fibrils
• Attached at the ora serrata/plars plana interface and at optic disc
What is the function of the vitreous
- Light transmission
- Supports the lens
o Mechanical and metabolic - Helps to maintain contact between the sensory retina and the choroid
- Prevents the globe collapsing – collapses due to not enough pressure
- Probably involved in retinal metabolism
Ageing changes to the vitreous
Older px have more liquified vitreous compared to younger px
Two things that happen worth age:
- synchisis - liquefaction of the vitreous
- syneresis - shrinkage of the vitreous
Vitreous floaters
Seeing the shadows of the vitreous
Seen in high light levels
Symptoms of posterior vitreous detachment
Symptoms:
- Sudden onset floaters
o Lines, dots, circles, squiggles
o Large ring (Weiss)
- Flashes of light
o Not all PVDs are accompanied by flashes
- No loss of vision
What is the incidence of PVD
Incidence ~65% >65
F>M
80% have 2nd eye involvement within 2 years
Occurs earlier in high myopia (-8.00) long axial lengths
Occurs more easily in those with cataract surgery
May be associated with trauma
Tobacco dust
Tobacco dust –aka schaffers sign
- RPE cells seen in the retrolental space
Released when a retinal break occurs
If you see tobacco dust assume a retinal break is present until proved otherwise – refer asap
Tobacco dust examination
Dilate pupil
Use a narrow slit bream and high mag
Focus behind the lens
May need px to look around
What is observed on the retina in proliferative vitreoretinopathy
Retinal folds are seen
Signs of a retinal detachment
Floaters
Flashes - photophobia
Curtain over vision
Reduction in visual field
Loss of vision
Why do we see floaters
- PVD – Weiss ring, gel collapse
- Vitreous haemorrhage – retinal vessels torn
- Retinal tissue – free floating operculum, large retinal tear
Why flashes
- Main job of retina = to see/receive light
- Altered tension on retina
- Retina “pulled” as eye moved
- Retinal stimulation gives rise to “flashes”
If you have a visual field loss it’s a…
Loss of retinal function
If you have loss of vision its a
Macula detachment
What are the types of retinal detachments
- Rhegmatogenous
- Exudative
- Tractional
Rhegmatogenous retinal detachment
- 1 in 10,000 ppl
- risk factors:
- PVD and vitreous liquefaction
- peripheral retinal degenerative changes
- myopia
- cataract surgery
- detachment in other eye
- trauma
What does rhegmatogenous rd look like
Horse shoe tear - cloudy looking
Exudative detachment
- serous fluid accumulates under retina
- examples:
- AMD
- posterior scleritis
- coats disease
In exudative detachment where does the fluid come
Serous fluid accumulates below the retina - layer just on top of the RPE
In RRD where’s the fluid
Fluid vitreous enters via a retinal hole or tear - in between the RPE and PRL
Tumours of the choroid may give rise to which RD
Exudative detachments
Such as
- Choroidal melanoma
- breast or lung metastases
Traditional retinal detachment
- Fibrotic change (scar tissue) may take place in the vitreous as a result to
o Advanced diabetic eye disease
o Vitreous haemorrhage
o Trauma
What does exudative retinal detachment look like
Looks like something big and cloudy taking over half the retina
What does tractional look like
Just looks like an area of the retina missing and smoothed over with no blood vessels seen
