Loss of vision Flashcards
Discuss macular degneration
Detected by the use of an Amsler’s chart
- Neovascular
- – visual loss may be sudden
- –central vision affected
- –distortion of straight lines
- –scotoma may be present
- –subretinal or intraretinal fluid and haemorrahge
Geographic atrophy
- more common
- progressive visual loss over many years
- sharply demarcated area of retinal depigmentation may be visible
Treatment
- bevacizumab
- laser photocougatlation for neovascular form
Discuss Central retinal artery occlusions
Acute retinal ischaemia develops from a sudden embolic thrombotic, vasculitic or vasospastic occlusion of a branch of the retinal artery or the cetnral retinal artery itself.
CRAO may be
1) non arteritic and permanent - due to platelet fibrin thrombi and emboli from atherosclerotic disease
2) non arteritic and transient - transient vasospasm due to serotonin
3) arteritic due to temporal arteritis and rare
In generall has a poor visual prognosis with spont resolution occuring in 1-8% of cases. Occurs most commonly in patient 50-70 years of age,
Discuss risk factors for CRAO
HTN Carotid artery disease cardiac disesase diabetes collagen vascular disease carotid artery dissection vasculitis -GCA cardiac valvular abnormalities sickl cell disease
Increased EOP
- acute gluacoma
- retrobulbar haemorrahge
- endocrine exopthalamos
Discuss clinical features of CRAO
Sudden (over seconds) painfless usually monocular severe vision loss
Exam: -VA usually worse than 6/60
marked RAPD
asymetric red reflex
-pale optic disc
-retinal white oedema of infraction (takes 24 horus to develop)
-Cherry red spot - due to surroundint oedema
Discuss IX of CRAO
As per TIA + CRP and ESR for vascultitis
Discuss management of CRAO
Time critical condition
- occlusions need to be reveresed within 90 minutes to prevent permanent retinal damage
- good resutls occasionally occur with reversal of occlusions within 3 hours if supplemental o2 is used
- discuss with othal prior to attempting any therapetuic maneuovres
Treatment option #Digital massage - direct oressure through clsoed eyelids for 10 -15 seconds followed by sudden release) #Hypercarbia using carbogen (95% o2 +5% c02) # reduction in IOP -Diruetics -topical beta blockade -acetazolamide 500 mg IV stat -anterior chamber paracentesis #Role of lysis is uncertain #Hyperbaric o2
Discuss Central retinol vein occlusions
Leads to congestion of venous blood and fluid in the intraretinal space taht may lead to secondary retinal ischaemia.
Subdivided into ischaemic and non ischaemia according to the degree of retinal cpaillary ischaemia seen on fluroescein angiography
-75% non ischaemia
2/3 of patient with the ischaemic tupe develop macular ischaemia
Discuss risk factors for CRVO
Older age HTN, Dyslipidaemia T2DM Vasculitides Hyperviscosisty smoking Hypercoaguable states particuarlly factor v
Discuss clinical features of CRVO
Onset over minutes and constrictive in nature
painless no floaters or phtopsia
Exam
usually can count fingers
VA and presence of RAPD are variable depending on the seveirty and time of onset
Abnormal red reflex
Fundoscopy
-blood and thunder retina - retinal haemorrhages and disc odema
-dilated tortuous veins
Discuss management of CRVO
Opthal consult Diagnose and treat underlying condition -antiVEGf, Intraveitral corticosteroid injection with a dexamethasone intravitral impant or triaminoclone -retinal photocoagulopathy -normilisation of IOPD -Cyclocryotherapy
Dischuss ischemic optic neuropathy
Fall into two primary type
-Anterior and posterior
AION can be furhter divided into arteritic anteiror ischaemic optic neuroapathy and the more common non arteritic anterior ischaemic neuraitphy
Patients with A-AION have cocurrent symptoms of temporal arteriesi including
- weight loss
- malaise
- jaw pain
- headache
- scalp tendenress
- polymyalgia rheuamtica
- low grade fever
Vision ;oss is often preceded by episodes of amaurosis fugax
Temporal arteririts fwith underlying A-AION is a clinical emergency - untreated vision loss becomes bilateral in days to week in at least 50% of cases. Patients should be admitted for high dose IV methylpred
Discuss retinal detachment and risk factors for the same
Tractional - a consequnce of contraction of a fibrous band that has formed in the vitreous.
Occurs when the neurosensory retina separates from the undelrying retinal pigment epithelium
Aetiology (rhegmatogenous, exudative, tractional)
#rhegmatogenous (most common cause, liquefied vitreous fluid enters the subretinal space, seperating the two retinal layers)
- Occurs in patients older than 45, more common in men and is associated with degenerative myopia
Trauma can cause this type of detachement at any age
#exudative - result of fuid or blood leakage from vessels wihtin the retina -associated with HTN, pre-eclampsia, CRVO, glomerulonerphtis, vascultiis and choroidal tumor.
Risk factors
- myopia
- cataract removal
- ocular trauma
- vitreous disease
Discuss clinical features of retinal detachement
History
- Appears like shade over the eye - initially peripheral becoming progressively central
- usually slow onset over hours
- flashes and floaters due to blood in the virteous and retinal traction and stimulation
- flashes are usually very brief in the temporal field and may be triggered by eye movemement
Exam
- parital field loss curtain defect
- acuity may be normla if macula not involved
- assymmetrical red reflex may be present
- RAPD may also be present if large
- Fundoscopy shjows areas out of focus with grey appearance elevated retina
- large amounts of associated vitreous haemorrahge may obscure the view of the retina
Ultraosund
-particulalry helpful if unable to visualise the retina
Discuss management of retinal detahcment
Opthal consultation, treatement with tamponade or retinopexy can prevent a retinal detachment taht does not ivolve the macula progressing to involve the macula. THe duration of macular detachement measured from the repated time of the loss of central vision is inversly proportion to end VA
Discuss vitreous haemorrahge
Results from bleeding into the preretinal space or into the vitreous caivity. The most common causes are diabetic retinopathy and retinal tears,
Symptoms begin with dark floaters or “cobwebs”in the vision and may progress over a few hours to painless visual loss.
RAPD is usually absent unless reitnal detachement is als present
Opthal consult mandoatroy
evaluation for retinal detachment in most cases\
other management options include observation, laser photocoagulation, vitrectomy.
