When Should You Dilate?

Flashes and Floaters:
The Optometrist’s Nightmare
Donald Cameron
BSc(Hons) FCOptom DipCLP
Cope 6758
Exp 12/1/04
How Great Is The Problem?
Migraine flashes
• Bilateral Homonymous disturbance
•
•
•
•
•
Incidence of breaks 330 in 10 000
Break/tear does not mean detachment
RD incidence only 1 to 5 in 10 000
Age: average 55, only 3-4% under 16
At risk:
–
–
–
–
myopes
aphakics
family history
trauma
– Diff to expect Px to express that
•
•
•
•
Central split then peripheral field defect
Usually < 1 hour duration
Flashes appear “jagged” in appearance
Not always followed by headaches &
nausea
• Usually history of migraine
When Should You Dilate?
Post Pole exam not enough
Symptoms
•
•
•
•
Recent onset / sudden increase in floaters
Any floater which reduces acuity
Flashing lights
Peripheral field loss
When Should You Dilate?
Dilate?
History
Signs
• Diabetics with
NV or fibrous membranes
• Inflammatory
vascular disease
• FH of RD
• Recent PVD
• Second visit with
vague symptoms
• Hx blunt trauma
• Aphakics
• Known naevus
– “Eales”
• Chororetinal scars
Pupil Dilation
Retinal Examination
• Direct Ophthalmoscopy
Take care & advise:
- Iris clip IOLs
• Headset Binocular Indirect
- Drivers?
- Shallow A/C angle
• Goldmann type 3/4 mirror contact lens and
slit lamp
- Warn of acute
• Superfield or Super-vitreo-fundus
– Not 1X Digital
pressure symptoms
Vitreous Anatomy
Vitreo-Retinal Adhesions
•
•
•
•
•
•
Ora serrata
Optic nerve head
Macula
Retinal blood vessels
Lattice degeneration
Pigment clumps
•
•
•
If sticky
with disease,
age or inflam
•
66% of weight and
volume of eye
99% water
1% collagen, hyaluronic
acid and electrolytes
Optically transparent
Aetiology of Floaters
• Vitreous syneresis
• Vitreous detachment
• Vitreous haemorrhage
– Diabetic
• Vascular inflammatory disease
– Eales disease
• Asteroid hyalosis
Examination
• Set SL to wide angles
• Direct focal and medium
width beam
• Dark room, strong
illumination
• Auxillary lens required
for posterior vitreous
– Often asymptomatic
Uncomplicated PVD: symptoms
Uncomplicated PVD: signs
• Thread like floaters
• Flashes of light/sparks
• “Spider” or “fly” in front of vision
• “Veil” descending over vision
• Vitreous syneresis
• Violent motion with
eye movement
• Weiss’ ring floater
(glial ring)
PVD Summary
• 31% over age 65 have PVD
– Female > Males
• Only 5% of PVD go on to produce retinal tears
• Only 10 - 20% Px with flashes and floaters have
retinal tears
• Retinal tears or breaks precede retinal
detachment
• Any ocular surgery increases risk
• Aphakia largest risk for RD
Complicated PVD: symptoms
• Numerous floaters
• Large peripheral “dense” floater
• Possible reduction in VA
• Flashes of light/sparks
• “Spider” or “fly” in front of vision
• “Veil” descending over vision
Retinal break signs
• Vitreous syneresis
• Operculum
• Retinal tear/hole
• “Tobacco dust”
How Sensitive is Tobacco Dust?
St. Thomas’ Study
– 200 suspect RD referred patients
– Optometrist ONLY allowed to look at vitreous
– Found tobacco dust in 25
• 15 had floaters only
• 9 had photopsia and floaters
– Ophthalmologist found 26 had retinal breaks
– Optometrist correctly diagnosed 25/26
– Optometrists correctly rejected 174 cases
Tobacco dust
The observation of
“tobacco dust” in
the anterior vitreous
indicates a retinal
tear until proven
otherwise
Do Flashes = Retinal Break?
• No!
• Photopsia is not a
‘stronger’ symptom
than floaters
• Can Px give accurate
history?
Telephone referral guidelines
• Tobacco dust does not produce specific
symptoms
• Presume summation of risk factors
– Older female + high myope + trauma + flashes + RD
F/H – Refer
– Young person + floaters few more than before + no
trauma + low myope + no photopsia
• Flashes in low illum only - PVD
• Flashes independent of illum – Ret Break
• Always “return if change in symptoms”
Referral Summary
• PVD
– No tobacco dust
– Low risk patients
– Advise 10% risk of RD within 3 months
– Review 6-10 weeks if you feel happier
– Return if change in symptoms
• Tobacco dust but no tear, flashes
– Refer urgently
• Tears are very difficult to find
Why Fuss About Degenerations ?
• Induce a localised weakness in the retina
• Vitreous is often liquified near a degen.
• Weakness means it is more likely to tear
• Tear + Fluid Vitreous = Detachment
Quadrantic Distribution
•
•
•
•
60% UT
15% UN
15% LT
10% LN
Lattice Degeneration Risk of RD
•
•
•
•
•
Myopes
Bilateral
Inferior nasal
Retinal thinning
Pigment epithelium
pigmentation
• Present in 40% of RD
Clinical Signs
• PVD / tobacco dust /
vitreous haem
• Darker overlying bvs
• Loss of choroidal pattern
• Opaque and raised retina undulation
• Reduction in IOP
– Drainage through choroid
– “Unhappy” ciliary body
• Mild anterior uveitis
Flap/Horseshoe tear
•
•
•
•
Pulls strip of sensory retina (no operculum)
Photopsia more likely
Usually larger
35% of symptomatic (photopsia) flap tears
produce RD
• 10% of asymptomatic tears produce RD
– Sup Temp tear allows SRF to leak to macula
Macular hole
• Caused by vitreous contraction
– Check for break in periphery
• Need vitrectomy
– Post op posture face down
• Face down up to 3 weeks
– air bubble
• Bubble holds macula flat
• Cataract later
Surgical Principles
Epiretinal Membrane
Retinal Coagulation
• Look for peripheral break
Over zealous treatment?
•
Seal retinal break
–
Laser
• Retina has to be flat
• Needs RPE for heat
–
–
Cryoretinopexy
Must find breaks before cryo
•
Inflammatory reaction
•
Sticky base
•
Chorio-retinal scar
Retinal coagulation
Effect of Surgery
• Blind spot where
scarring
• Prevent movement
of vitreous into
subretinal space
Pre Surgery
Is it safe?
Post Surgery
Post RD Op Reassurance?
•
•
•
•
•
No definitive test
No reason for concern if asymptomatic
No indentation in asymptomatic post op
Symptoms indicate investigation
Return if change in symptoms
– Floaters, flashes, curtain
Retinal tear – laser scarring
Post op scarring
Retinal tear – laser scarring
Post op scarring
Retinal Break
& Flap
Sealed Area
Retinal tear – laser scarring
Retinal Break
& Flap
Post op scarring
Sealed Area
•
Large Pre-Op Tear
Post Surgical Appearance
Summary
Summary
what to do when...
what to do when...
Asymptomatic old PVD
– Dilate see routinely
•
Recent PVD now asymptomatic
– Dilate then review 6-10/52 OR refer
– ?refer if any doubt / risk factors
•
Acute flashes, no PVD but vitreous degen
– Dilate and peripheral exam
– see every 6/12 OR refer via GP
•
PVD and acute flashes / floaters
– see 6-10 weeks or refer
• PVD and tobacco dust
– reduced IOP
– dense peripheral floater
– always refer to casualty
• PVD, tobacco dust and retinal breaks
– refer to casualty
• Tobacco dust remains after op
– Only good test first time round