Opthalmology Flashcards
State 4 RFs for cataracts
- age- affects 50% of those over age 65
- smoking
- diabetes
- systemic corticosteroids
- eye trauma, female, uveitis, UV exposure, poor nutrition, alcohol are smaler RFs
- retinitis pigmentosa lol- pt in 20s w/ night vision loss, feild defect, fhx and black peripheries on fundoscopy (google it)
- Downs
Describe the pathophys of catartacts in adult and what may cause in a child?
- There is deposition of new crystallin lens fibres with age, old ones are not removed
- New deposition disruption of the carefully composed structure leading to protein aggregation and so clouding and light scattering
- 2nd factor= accumulation of yellow- brown pigement making reading more difficult as affects contrast
- Paediatric cataracts may be caused by galactosaemia, genetic, TORCH infection, diabetes, traumatic or post radiotherapy
Describe the clinical features of cataracts
- gradual painless loss of vision- not improved by viewing through pinhole
- haloes around lights and problems watching tv
- problems recognising faces and diplopia in one eye
- defects in red reflex
- lens appears brown or white when bright white light shone on eye
- pupillary reactions normal
How is cataracts managed?
- extracapsular lens extraction or phacoemulsification (lens liquidied with USS probe and then aspirated before replacing it with artificial lens)
- decision to treat depends on affect on QoL an risk vs benefit rather than specific acuity
State 4 early complications of cataracts surgery
- poor vision (inadequate correction of refractive error or pre- exisitng eye condition)
- capsular rupture with vitreous loss- endopathalmitis risk
- protruding or broken sutures
- trauma to iris
- wound gape or iris prolapse
- anterior chamber haemorrhage
- vitreous or choroidal haemorrhage
State 4 late complications of cataracts surgery
- posterior chamber opacification: vision can usually be restored with laser capsulotomy
- cystoid macular odema
- uveitis
- retinal detachment
- open or closed angle glaucoma
- ARMD
- dysphotopsias: unwanted optic phenomena due to light artefacts reflecting off IOL
What is primary open angle glaucoma
Progressive, chronic condition characteristed by:
- Adult onset
- Intraocular pressure >21mmHg- however 20-52% have normal tension glaucoma
- Open iridocorneal angle- flow is simply reduced through the trabecular meshwork
- Glaucomatous optic neuropathy
- Visual field loss compatible with nerve fibre damage
- Absence of underlying cause
- Usually bilateral but asymmetrical
Give 4 RFs for primary open angle glaucoma
- age (rare before 40)
- fhx
- afrocarribean
- ocular htn
- myopia, retinal disease diabetes, systemic htn
describe the clinical features of primary open angle glaucoma
- Most asymptomatic as vision loss is initially to peripheral vision so when they notice it is too late and damage is permenant
- May be picked up on checking IOP and part of visual fields by optician or by GP looking at optic disc
- Gonioscopy is used to measure angle between cornea and iris
- Corneal thickness needs to be done as will increase IOP reading falsely
- Goldmann tonometry is used to measure IOP- usually raised (9-21 is normal)
- Optic disc exam- increase in cup size in relation to disc ( ratio >0.7)
- Loss of peripheral visual fields (measure with perimetry)
How is primary open angle glaucoma managed?
- topical beta blocker (timolol) or prostaglandin analogue (latanoprost) 1st to reduce IOP
- miotics and sympathmiometics can also be used
- laser and surgical management if 2 of these fail (selective laser trabeculoplasty)
- Even if IOP isnt raised they’re still given medication to lower it
What can cause angle closure glaucoma?
- insidious/ primary
- hypermetropia
- lens bulging forward as a result of swelling eg blood(hyphaema), blood vessels (diabetic eye disease) or protein (hypertensive uveitis)
describe the clinical features of acute angle closure glaucoma
- severe rapidly progressive pain in and around the eye
- blurred vision/ visual loss
- marked red eye- reddest around cornea
- pupil fixed and dilated, sometimes hazy cornea
- hard globe (press with eye lids closed and will be hard and tender)
- IOP raised (often 50s or more)
- N+V common
- attacks often start when something dilates pupil
- coloured haloes around lights (subacute attacks)
How should acute angle closure glaucoma be managed?
- give all glaucoma meds that arnt contraindicated (timolol, lantoprost, pilocarpine, maxidex etc)
- IV acetazolamide (500mg over 10 mins) and lay supine
- if no response in 1 hr and U&E normal give hyperosmotics such as mannitol
- If this fails or U&E abnormal, iridoplasty can be done
- systemic analgesia and antiemetics
- laser peripheral iridotomy within a few weeks of the attack, sometimes lensectomy
- top steroids often given bc eye becomes inflammed
- pilocarpine drops often given to constrict the pupil and help unblock the drainage
Give 3 complications of acute angle closure glaucoma
- permanent visual loss
- repetition of attacks
- attack in other eye
- central retinal vein or artery occlusion
Describe and explain the 5 retinal findings in diabetic retinopathy
- Microvascular occlusion causes retinal ischaemia and leds to AV shunts and NEOVASCULARISATION .
- Leakage results in intraretinal haemorrhages and MACULAR ODEMA
- MICROANEURYSMS: physical weakening of capillary walls which predispose them to leakages
- HARD EXCUDATES precipitates of lipoproteins leaking from retinal blood vessels
- HAEMORRHAGES: rupture of weakened capillaries, appearing as small dots/ larger blots or flame haemorrhages that track along nerve- fibre budles in superficial retinal layers
- COTTON WOOL SPOTS- axonal debris build up due to poor axonal metabolism at margin of ischaemic infarcts
Describe the grading of diabetic retinopathy
- Non proliferative (MILD (<2 microaneurysm) MOD (mciroa + intraretinal haemorrhages +/- cotton wool spots, venous bleeds) SEVERE/ PRE-PROLIFERATIVE (number of change in number of quadrants)
- Proliferative (non high risk (no changes within 1 diameter of optic disc) and high risk (large new vessels on disc or everywhere, retinal detachment or pre retinal haemorrhage)
Describe the grading of diabetic maculopathy
- focal or diffuse macular odema
- ischaemic maculopathy (normal but reduced acuity and ischaemia seen on fluorescein angiography)
- clinically significant macular odema: thickening or hard exudates which are of certain size/ distance from the fovea
Describe the clinical features of diabetic eye disease
- Painless gradual reduction in central vision
- Haemorrhages result in sudden onset dark painless floaters which may resolve over several days
- Severe haemorrhages result in painless visual loss
- Spots within the red reflex suggest vitreous haemorrhage
How is diabetic retinopathy managed?
- laser photocoagulation treatment if neovascularisation to induce regression and also helps reduce central macula thickening
- diabetes, BP, lipid control
- sometimes vitrectomy after preretinal/intravitreal bleeds
How is diabetic maculopathy managed?
- anti VEGF injections
- intravitreal triacinolone (steroid) injections
give 4 complications of diabetic eye disease
- macular ischaemia
- vitreous haemorrhage
- retinal detachment
- glaucoma
Describe the pathophys of dry and wet ARMD
Dry: soft drusen in macula + atropy of retinal pigment epithelium causing gradual vision loss
Wet: new blood vessels grow in choriocapillaries under the retina, they lead to haemorrhage and scarring, progression varies from 3 months to 3 yrs. end point is scar formation known as disciform macular degeneration
Describe the clinical features of ARMD
- painless deterioration in central vision (esp near vision) in person age >55
- loss of contrast sensitivity
- size or colour of objects appear differnt in each eye
- flashing or flickering lights and glare
- In wet ARMD straight lines appear crooked or wavey (due to macula odema) and visual deterioration is much quicker, often get profound sudden loss, flashers and floaters in event of a bleed
- yellow deposits called drusen seen in macula area on opthalmoscop
How is ARMD diagnosed?
Ocular coherence tomography (OCT), fluorescein angiography if wet ARMD suspected
How is dry ARMD managed?
- no treatment but slow progress:
- stop smoking
- visual rehab
- nutritional supplements (vitamins A,C,E, lutein, zinc, copper
- lots of leafy greens and fresh fruit
how is wet ARMD managed?
- intravitreal injections of VEGF if macula odema
- laser photocoagulation for neovasc
- photodynamic therapy
- macular translocation (NICE doesn’t recommend)
- implanted lens systems in future
Describe the pathophys to retinal vein occlusion
- Commonest cause is thombus formation
- Other causes inc vein wall disease and external compression (arteriole thickening compresses the vein within the same sheath)
- Backlog of stagnated blood + hypoxia = extravasation of blood futher stagnation
- Ischaemic damage stimulates VEGF
leading to neovascularisation so haemorrhage + glaucoma (clogs drainage system)
Describe the clinical features of branch and central retinal vein occlusion
Branch:
- unilateral painless blurred vision + altitudinal visual field defect and visual distortion. Fundoscopy= vascular dilation and tortuosity of vessles and haemorrhages in one area
Central:
- sudden unilateral painless loss of vision
- flame haemorrhages and disc odema on fundoscopy
- if ischaemic: marked pupillary defect, cotton wool spots, occasionally detachment
How is retinal vein occlusion managed?
Branch: panretinal photocoagulation if develop macula odema or neovascularisation, dexamethasone, anti VEGF, triamcinolone injections
Central: no proven treatment, modify RFs and keep pain free, non ischaemic will get pan retinal photocoagulation if neovascularisation occurs
Describe the pathophys of retinal artery occlusion
- Central retinal artery is branch of ophthalmic artery (brach of internal carotid)
- It supplies optic disc and then branches into superior and inferior and then again into temporal and nasal which supplies the 4 quadrants of the retina
- Cilioretinal artery is present in 30% ppl and can help preserve macular in some people after CRAO
- Aetiology is same as any stoke but most are embolic from carotid artery disease, some are retrobulbar masses leading to optic nerve and CRA compression
Describe the clinical features of retinal artery occlusion
- Central retinal artery: sudden unilateral acute painless loss of vision, usually to counting fingers (if worse - ophthalmic artery affected)
- 10% get amarosis fugax- curtain coming down
- Examination= afferent pupillary defect + pale retina and cherry red spot + attenuation of vessels + carotid bruits/ murmers/ AF/ HTN
- Branch: defect in one quadrant/ half of vision, retinal pallor only in area affected
How is central retinal artery occlusion managed?
- If present within 90-100 mins= firm ocular massage (may dislodge obstruction but rarely works)
- Lowering IOP within anterior chamber paracentesis + acetazolamide
- Dilation of artery (GTN, inhaled carbogen or hyperbaric oxygen)
- Intra arterial fibrinolysis through local injection or urokinase into proximal part of ophthalmic artery
- Long term: identify an treat underlying cause, manage RFs, carotid endarterectomy, vision aids, DVLA notification
- Prognosis is poor
Describe the pathophys of retinal detachment
Most are preceeded by posterior vireous detachment (PVD), which causes traction on retina and a tear, liquefied vitreous seeps under retina and causes it to detach.
Can be rhegmatougenous (commonest, as above, tear is between the sensory and pigment epithelium) or non- can be exudative (primary damage of RPE causes subretinal fluid in and pushes retina off) or tractional (rare)
Give 5 RFs for retinal detachment
- Mypoia (short sightedness- increased PVD risk)
- Fhx
- Previous history of RD in either eye
- Age
- Marfans
- Diabetic retinopathy, eye injury, retinal vein occlusion, retinopathy of prematurity increase risk of non rhegmatogenous tractional RD
- Inflammatory condition, vascular disease, maculopathy and malignancy increase risk of non rhegmatogenous exudative RD
describe the clinical features of retinal detachment
- new sudden onset floaters (often a shower) indicate a PVD has occured
- then they get new onset flashes of light as the vitreous pulls the retina away
- then sudden onset painless progressive visual field loss (described as shadow)- starts peripheral but comes in
- if macula detaches, visual acuity is reduced
- RAPD if macular or half of non macula retina detaches
- grey or folded red reflex
- see a sheet of sensory retina billowing towards centre of globe, or a visible tear, on fundoscopy
how is retinal detachment managed?
- vitrectomy and scleral buckling for detachment repair
- cryotherapy or laser photocoagulation to repair retinal holes/ tears
- most RDs not involving macular are repaired same day- if macula involved within 5 days
- strict bed rest and hold head in particular position to stop progression before surgery
- prevention: protective eyewear for severely mypoic pts playing contact sports, repair tears/ holes, recognise PVD early
What words are used to describe a strabismus (squint)
eso- inward deviation
exo- outward deviation
hypo- downward
hyper- upward
What is the difference between a concomitant or incomitant (paralytic) squint?
concomitant= the squinted eye can move normally if tested separately from the good eye. Incomitant= cannot move even when good eye is covered
what is the leading cause of a squint in adult and child?
adult- stroke (then thyroid eye disease)
child- refractive errors (then cerebral palsy, downs, hydrocephalus, SOLs etc)
How are concomitant squints managed?
Almost all due to refractive errors- correct these first.
If <8yrs, eye patching +/- cycloplegic drops in good eye can bring bad eye in and force it to work- takes up to 18 weeks.
If treatment fails, surgical realignment with recess and resect- cosmetic effect isn’t permanent and rarely restores binocular vision
What is the difference between monocular and binocular dipolopia? List common causes for each
Monocular- when double vision remains on occulsion of uninvolved eye-> NOT STRABISMUS- usually refractive error or cataracts.
Binocular- double vision corrected when either eye is occluded. CONCOMITANT malalignment= strabismus. INCOMITANT malalignment= CN palsy, NMJ disorder (MG), restrictive disease (thyroid or blow out #), ocular myopathy, ocular myositis, supranuclear palsy.
No malalignment= MS/MG, physiologic/ non organic
State 4 causes of a incomitant strabismus
- CN palsy
- ocular myositis: idiopathic nonspecific inflammation of extraocular muscle, presents in early adulthood, also get pain on moving eye. Resolves spontaneously in 6 weeks
- ocular myopathy: rare genetic progressive bilateral reduction in eye movement, starts before age 20, often ptosis also.
- thyroid eye disease
- myasthenia gravis: worse at end of day, intermittent, ptosis, fatiguability
Describe the CFs and causes of a CNIII palsy
CFs: down and out eye, ptosis, USUALLY large pupil w/ partial/ completely impaired pupil response- direct & consensual reflexes affected (pupils not always affected)
Causes: ischaemic microvascular disease or cavernous sinus syndrome (usually pupil sparing), aneurynsm (CT angio URGENTLY), tumours, trauma, pituitary apoplexy, herpes zoseter, leukaemia, ophthalmoplegic migraine, raised ICP
Describe a CNIV palsy and state 3 causes
Eye up and out a bit, cant move down and in, binocular vertical diplopia, difficulty reading, tilted head. Causes inc trauma, vasculopathy, demyelinating disease, congenital or idiopathic
Describe the CFs and causes of a CNVI palsy
horizontal diploia- worse for distance than near vision and on lateral gaze. Cant move eye outwards. Causes inc vasculopathy, trauma and idiopathic. Less common causes inc raised ICP, cavernous sinus syndrome, MS, GCA, inflammation, infections
What are entropians and extropians?
entropian= lower eyelid turns in extropian= lower eyelid turns out