Macula Flashcards
What makes up the macula?
Fovea 1.5mm
Foveola 0.35mm
FAZ
Umbo
Which is the thinnest part of the macula?
Foveola
Where is the macula located?
B/w superior and inferior temporap arcades
Where is the reflex observed in the macula?
Umbo
Which aspect is important for high resolution in the macula?
Fovea
Which part of the macula holds no blood vessels?
FAZ
What part of the macula help reduce the degradation of the image?
Foveola, the laterally displaced RGC
How do we assess the macula function?
- VAs
- Amsler chart
- Retinal imaging and fundoscopy
What test would indicate that the reason behind reduced vision is pathologological and not a refractive error?
Pinhole test
How is an amsler chart used?
Monocular and at 30cm
Wearing the correct reading add for dist
Not use varis
Ask- “look at the central fixation dot and if there is any distortion or scotoma
Whats the best way to view subtle changes of the macula?
OCT
What is the most common cause of irreversible visual impairment in the UK?
ARMD
What is the prevalence of AMD?
AMD prevalence increases with age
30% of > 75 yrs effected by AMD
4.8% >65 yrs diagnosed with Advanced AMD
Rises by 12.2% >80 yrs
What are the risks factors?
- Age
- Ethnicity— Caucasian
- Genetics— 1st degree 3x risk
- Gender— Females
- Smoking— 2x
- Obesity
- Systemic HT
- High fat diet
- CVD history
What 2 types of disease processes are there in AMD?
Geographic atrophy
Wet
How prevalent of all AMD is geographic atrophy compared to wet?
Geographic 90%
Wet 10%
Where is the earliest change of AMD?
Level of Bruchs membrane
What is the role of Bruce’s membrane?
Regulating transportation of toxic metabolic waste from retina to choroidal blood vessels.
What happens to Bruchs membrane with age?
BM thickens
Reduces permeability
Inhibits toxin removal
Waste products i.e. lipofusin accumulate
What are the sxs of Dry AMD in each stage?
Early- Asymptomatic
Progression- Gradual deterioration in Central vision
Advanced- Difficulty with fine detail resolution
Severe cases- Aware of central scotoma
What are the sxs of wet AMD?
Painless Sudden onset Blurred Distorted Central vision (metamorphosis) Unilateral
What are the signs of AMD?
Drusen (hard, soft and calcified)
If Unilateral, how likely is a px to develop wet in the fellow eye?
37% will develop in a year
What is the 1st visible sign of AMD?
Drusen
What is drusen and how do they effect vision?
Waste products made up of lipids and collagen. They disrupt the orientation and organisation of RPE resulting in depigmentation and hyperpigmentation.
At which age are drusen common in?
50 yrs +
When does drusen indicative of AMD?
Size and number
What are the black arrows indicating
Soft drusen
What is this image showing
Calcified drusen
When is hard drusen a low risk of visual impairment?
When its without other signs
At what stage of AMD is geographic atrophy present?
End stage
What happens to the retinal tissue when there is geographic atrophy?
Reduce thickness and exposes underlying blood vessels of choroid and choriocappilaries
What is the hallmark or wet AMD?
Choroidal neovascularisation
What 2 things are the arrows pointing too and can they be referred as?
Top arrow hyperpigmentation
Bottom arrow hypopigmentation
Referred as ‘pigment clumping’
Whats the prevelance for dry to become wet in AMD?
10-15%
What are risk factors for CNV and why?
Degeneration of RPE
Confluent soft and geographic
These are angiogenic stimulus which is ischaemia
Where does new blood vessel arise from?
Endothelial cells from choroidal capillaries
What is the subretinal neovas membrane referring to?
A fibrovascular membrane supporting the structure of the new blood vessel
What are the signs of subtle fibrobascular membrane?
Grey, green, yellow colour
Difficult to identify
Obscured by RPE, BM, SRL
May not have leakage
If there is no haemm but a fibrovascular membrane is spotted, what action is taken?
Urgent referral whether its suspected or confirmed. Haemm is inevitable
What is being shown here and when is it seen?
Disciform scar, seen on the end stages of wet AMD
What other signs could be seen with a desciform scar?
Retinal and subret haemm haemm and oedema. This gives the surface and irregular and elevated during ophthalmoscopy
In cases of dry AMD, when is referral not needed?
When the px is Asymptomatic…
…although counselling is needed about the implications to potential vision loss. 12/12 recall
When is referral needed for dry AMD pxs?
- Unsure of retinal signs despite dilation
- Symptomatic dry AMD
- Dry related vision loss
What key aspects of dry AMD would the px need counseling of?
- No licensed tx
- Slow progression
- Continue to deteriorate vision
- No impact in early stages
- Possibly develop wet
- Make aware of wet sxs: sudden reduction in VA
- Self monitor- Amsler chart
- Compare vision
- Information on modifiable risk factors
What 2 pigments are present in the macula that aids in protecting against free radicals?
Lutein and zeaxanthin
Where can Lutein and zeaxanthin be found?
In leafy greens I.e. spinach and kale
The body cannot produce these
Why does the retina have a high amount of free radicals?
Its due to it high metabolic activity
Aside from Lutein and zeaxanthin, what other antioxidants can help protect the macula?
Vitamin c
Vitamin e
Cartenoids
What actions are taken for those with advanced dry AMD?
Refer to the GP
Theyay benefit from LVAs
What merits an Urgent referral in AMD?
Exudative/ wet AMD…
…especially if sudden onset reduced vision. Even if signs are not clear
Where are wet AMD pxs sent and how?
Macula clinic via Fast track
Once wet pxs are referred, how long till they are seen by ophthalmologists?
2/52
If a fast track is unavailable locally what other options are there?
On call at local HES Same day
OR Refer A+E
What is the primary tx for wet AMD?
Intravitreal injections (Antivegf tx)
Which type of VEGF is responsible for mediating the process of new blood vessels?
VEGF A
What are the common anti VEGF treatments called?
Ranizumab- Lucentis
Aflibercept- Elyea
Bevacizumab- Avastin
What are the non- AMD forms?
Cystoid macula oedema Central serous retinopathy Epiretinal membrane Macula hole Myopic degeneration Hereditary macula dystrophy
Where is CMO usually located?
Sensory retinal layers AKA intraretinal layers
Where is the fluid from CMO originate from?
Intravascular peri foveal ret capillaries which are dilated
What is the sign of early stages CMO?
Reduced/Abolished reflex
What is the common cause of CMO?
Cataracts expansion AKA Irvine-Gass syndrome
What are the less common cause of CMO?
Intraocular inflammation (post uveitis >ant uveitis)
Diabetic retinopathy
C/BRVO
What are the sxs of advanced CMO?
Sudden
Painless
Blurred V
Distorted Central vision
How is CMO treated?
Resolve usually without any treatment, may need to treat underlying condition
Wht ate the pharmaceutical options for treatment of CMO?
- CAI- increase fluid outflow into choroid
- Corticosteroids- reduce inflammation
- Laser photocoagulation- stimulate repair of BRB
What are the optometric management?
Depends on the cause:
Cataract- refer routinely
Vascular- Call HES for advice
Uveitis suspicion- Emergency referral same day
Which other condition shares the same symptoms as CMO?
CSR Central serous retinopathy
Where does the fluid originate from in CSR?
Fluid from choroid, break down of Outer BRB
What is CSR prevelance?
Males
Age 20-50 yrs
Unilateral
30% recurrent
How would CSR be managed?
If sxs- discuss with local HES
Treatment unlikely as resolves spontaneously
How is epiretinal membrane formed?
Disruption from tractional forces in PVD causing ILM cells to proliferate and form epirtinal membrane
What are other causes of epiretinal membrane?
Most ERMs idiopathic
Retinovascular/intraocular inflamm
What can bunched up or concertinaed ERMs lead to?
Macula hole
What surgery would be appropriate for a ERM?
Virectomy and membrane peel
What is visible sign of ERM?
Reflective shimmer around the macula
Wha is cellophane maculopathy?
Early stage sign in ERM that doesn’t effect VA
How is ERM differentiated from macula pathology?
Slow progressing 12/12 to develop
If VA is effected in ERM, What action is taken?
Routine referral via GP
…if not effected than a a normal routine recall of 12/12
What causes a macula hole?
Vitreo ret traction which warps the fovea retinal structures. As adhesions are strong here this can cause retinal breaks
Where is the break in retina limited to?
Sensory layers, RPE is still intact
Which test would be used to determine the effected break?
Wazke-allen test- 0.5 disc diam width beam centered on the macula
A break in the beam would suggest the shape of the break
Who are more prone to macula holes?
Females
Myopes
What are the early stages of a macula hole?
Small diam lesion
Little to see
Visible sign- reduced/absent fovea depression + red/yellow spot ring a fovea
Mild reduced VA, Blurred Vision and distortion
Sudden onset, unilateral , painless
When is a macula hole unlikely to resolve spontaneously?
Intermediate/ end stages
If left untx may leave a permanent Central vision loss
What is dependent on the successful of the tx?
The time elapsed since inset
Why isnt there a treatment need for a macula hole compared to an RRD?
Slower progressing that RRD
What is the referral route for the different stages of the macula hole?
Ealry/interm- referral via GP (1/12)
End- routine referred
Cannot rule out diff dx- refer suspected macula hole via fast track AMD
How likely is it to effect the following eye?
By 15%
Wha is the ophthalmological management?
Relieving VRT via virectomy
What is the alternative to virectomy and what does it do?
Intravitreous injection of ocriplasmim- helps dissolve proteins in adhesions
Why is myopic degeneration considered a non AMD form?
Retina and choroid are thinned which makes them susceptible to atrophy.
Wha are the signs of myopic degeneration?
- PPA
- Chorioretinal atrophy around ONH
- Thinned retina
- Optoc disc tilt
- Possibly breaks on BM
- Excessive axial elongation
- Washed out red/yellow colour
- Hyperpigmentation
- Exposed choroidal blood vessels
- Possible similarities to end stage dry AMD
What are the sxs of myopic degeneration?
No sxs!
Gradual atrophy- resultant loss of LR function
Similar to dry AMD-
Gradual, painless, bilateral, asymmetric
What are the rare symptoms of myopic degeneration?
CNV Sudden Unilateral Blurred Distorted
When is myopic degeneration considered for referral?
Suspicion/sign CNV development
VA drop…. refe routinely via GP
What are the hereditary macula dystrophies?
Stargardts disease-
Pattern dystrophy
Cone dystrophy
What are the typical sign of cone dystrophy?
Late stage- bulls eye and symmetrical in BE
What is indicative of a progressing cone dystrophy?
Onset adulthood
Reduced VA and colour vision
Which disease falls under a vitelliform dystrophy and what are the typical signs?
Best disease
Signs- egg yolk lesion at macula
Lipofuscin build up at macula
How would hereditary macula dystrophy be managed?
Caution!
Reduced VA- Refer via GP
No tx
How can hereditary macula dystrophys be confirmed?
ERG and LVA assessment needed
What is this called and what is it a result of?
Petaloid
This is fluid like cysts accumulated resulting in laterally displaced ganglion cell layer
What 2 aspects are being shown here?
Top arrow PED
Bottom arrow Serous detachment
What is causing the distortion of the retinal layers?
ERM
