Acute and Chronic Visual Loss Flashcards
What visual acuity is deemed as blind?
< 3/60 in the better eye
What is the most common cause of blindness in the world?
Cataracts
What visual acuity can you not drive beyond?
6/12
The closer the cataract is to the _____ part of the eye, the worse the cataract is
Nodal
Is a cataract better in bright or dim light? Why?
Dim light
Some of the light may get passed the opacity due to the dilated pupil
What happens to the lens with increasing age?
It grows
What is the triad of congenital rubella?
Sensory problems
Cataracts
Heart problems
What is an autosome?
A non sex chromosome
What is the commonest cause for amblyopia?
Refractive error
What is the vascular layer of the eye?
Uvea
What can uveitis cause?
Cataracts
What can steroids for an inflammatory condition cause?
Cataracts
What is the eye very sensitive to?
Trauma
Cataracts can make you not see what colour?
Blue
What happens to the refractive index of the lens in cataracts and what does this result in?
Increased
Leads to increased bending of light
So focuses in vitreous
What is index myopia?
Presbyopia
Goes away and then cant see far away
What holds the lens from the Ciliaris muscle?
Zonules
Where does the aqueous humour exit the eye?
Via the trabecular meshwork
Where is the aqueous humour made?
Ciliary body
What is the sensitive part of the eye?
Macula
What is the central part of the macula called? What is the features of the fibres of this?
Fovea
The fibres are spread apart so that light can go directly on the retina
Where is the blind spot?
On the optic nerve
Why is the optic nerve a blind spot?
As the fibres dont let the light through
What is a scitoma?
A non seeing area
What does a non -ve scitoma in glaucoma mean?
They are unaware that they cant see
What do beta blockers do in the treatment of glaucoma?
Stop production
What do prostaglandins do in the treatment of glaucoma?
Help the drainage
How does a trabeculectomy work?
Fluid comes through the iris and through a trap door (fistula)
What would be seen in endophlemitis?
Pus in the eye
What is absent in closed angle glaucoma?
Light reflex
Presentation of closed angle glaucoma
Absent light reflex Mid dilated pupil Vomiting Abdominal pain Extreme pain in eye Red eye
Why does closed glaucoma cause vomiting and abdominal pain?
Due to stimulation of the vagal nerve
Cause of a pale retina
Central retinal artery occlusion
What does a cherry red spot mean?
Infarcts except from at fovea, as see choroid circulation
Where is the most likely source of an eye embolus?
Carotids
What does CRAO stand for?
Central retinal artery occlusion
Treatment of CRAO
Diamox Massage Topic glaucoma medications AC parenthesis Increased pCO2
What is the aim of treatment of CRAO?
Lower IOP to try and move the embolus along
Why is pCO2 treated to increase in CRAO?
Increased vasodilation
How is pCO2 increased?
Breath into a paper bag
Risk factors for a vein occlusion in the eye
HTN DM Smoking Increased IOP Blood conditions e.g. myeloma
What does VEGF do?
Promotes new vascular growth in the eye when there is ischaemia
Treatment of rubeosis Iridis
Laser - gets rid of vessels
Elimination of Veg F
Steroids
Investigations of temporal arteritis
CRP
Biopsy
What condition overlaps with temporal arteritis?
Polymyalgia rheumatica
Treatment of temporal arteritis
High dose of prednisolone quickly
What can happen if temporal arteritis is not treated?
Can become blind in one eye and spread to the other
What does PH stand for?
Pinhole
How are cataracts named?
Depending on where is affected
Will a true cataract recur? What can happen?
No
but epithelial cells can proliferate and thicken the capsule again - however this is not cataracts
How common is hypopia?
Rare
Pathology of hypopia
Fluid level of pus in the anterior chamber
What is a hypopia?
Intraocular infection
What may a hypopia need?
Vitrectomy
Prognosis of hypopia
Poor
Who gets hypopia?
Trauma
Immunocompromised
On looking at an eye, how can you tell which vessels are arteries and which are veins?
Blood is darker in the arteries
What is the distribution of symptoms of a branched retinal vein occlusion?
Just in the quadrant
Types of retinal vein occlusion
Central
Branched
Features of central retinal vein occlusion
Sudden loss of vision in affected eye
Blot haemorrhages
Begorged veins
Red/erythematous optic disc
What condition has the same eye symptoms as central retinal vein occlusion but look different clinically?
Central retinal artery occlusion
Features of the eye in central retinal artery occlusion
Cherry red spot
Pale retina
What is usually associated with central retinal vein occlusion?
HTN
What is usually associated with central retinal artery occlusion?
Embolus
Hypoperfusion
What can cause CRAO and therefore what must be checked?
GCA
Inflammatory markers and any other symptoms
What is the most common cause of blindness in the UK?
Age related macular degeneration
What is ARMD characterised by?
Degeneration of retinal photoreceptors that results in the formation of drusen which can be seen on fundoscopy and retinal photography
Two types of macular degeneration
Dry (90%) vs Wet (10%)
Early vs late
What is dry macular degeneration characterised by?
Drusen-yellow round spots in Bruch’s membrane
Geographic atrophy
What is wet macular degeneration characterised by?
Exudative and choroidal neoavascularisation
Leakage of serous fluid and blood can subsequently result in a rapid loss of vision
Which is the type of macular degeneration has the worst prognosis?
Wet
RFs for age related macular degeneration
Advancing age Smoking FH HTN Dyslipidaemia DM
Presentation of age related macular degeneration
Reduction in visual acuity Difficulties seeing in the dark Fluctuations (day to day) in visual disturbance Photopsia Glare around objects
What is photopsia?
A perception of flickering or flashing lights
Signs of age related macular degeneration
Disortortion of line perception
Fundoscopy
- drusen
- yellow areas of pigment deposition in the macular area
In wet
- well demarcated red patches may be seen (intra retinal or sub retinal fluid leakage or haemorrhage)
Investigations of age related macular degeneration
Slit lamp
Flurorescein angiography
Ocular CT
Treatment of age related macular degeneration
Moderate dry category ARMD
- zinc + anti oxidant vitamins A, C and E
anti-VEGF
Laser photocoagulation
