Opthamology Flashcards
What are the causes of conjunctivitis? What are the clinical features of each?
Allergic - generalised redness, serous discharge, itchiness, bilateral
Viral (adenovirus, Herpes simplex) - unilateral, generalised redness, serous discharge
Bacterial (S.pneumoniae, S.aureus, H.influenzae) - generalised redness, itchiness, purulent discharge, foreign body sensation/gritty
What is the management of each cause of conjunctivitis?
Allergic - antihistamine eye drops
Viral - self limiting, don’t touch eyes, can use artificial tears
Bacterial - normally self limiting, chlorampenicol drops in severe cases
What type of HSV causes conjunctivitis and how?
HSV 1 normally but HSV2 in neonates from contaminaiton in vaginal delivery.
What is blepharitis?
Inflam of the eyelid = sore and itchy crusty eyelids. Is a chronic condition and can’t be cured. 50 yo = average presentation.
What are the causes of different types of blepharitis and some specific signs for each?
Ant - staph, seborrheic dermatitis. Trichiasis, poliosis, madarosis
Post - affects meibomian gland. dilated and obstructed meibomian glands, chalazion
What do these words mean:
Trichiasis
Poliosis
Madarosis
T = eyelashes turning in
P = depigmentation of eyelashes
M = loss of eyelashes
What is the management of blepharitis?
Can’t be cured but:
Conservative management - warm compresses and clean lids reg, avoid eye make up and contact
Medical - ocular lubricants, steroids or abx
Can refer if not resolving or suspect underlying condition, visual change/loss, cellulitis signs and eyelid deformity
What do entropion and ectropion mean?
Entropion = eyelid turning inwards
Ectropion = eyelid turning outwards
What is keratitis? What are the CF?
Inflam of the cornea.
CF - eye pain, watering, photophobia, reduced vision, hypopyon
O/E - corneal infiltrate and opacification
What are corneal infiltrates? What is epiphora?
What is hypopyon?
Gray haze around cornea, looks a bit like corneal arcus
Epiphora - excess tearing of eye
Hypopyon - collection of pus behind the cornea in the ant chamber
Herpes simplex keratitis:
- CF
- O/E
- Treatment
Pain, photophobia, epiphora.
Can see dendritic ulcers w fluorescein, most common cause of corneal blindness.
Topical acyclovir.
What is the pathophysiology behind central retinal artery occlusion?
Int carotid artery branches into the ophthalmic artery which supplies the eye. This splits into retinal (retina) and ciliary (choroid) arteries.
What is the presentation of CRAO?
- Sudden onset painless unilateral loss of vision due to ischaemia of the retina
- Central area of vision spared due to cilioretinal artery supply to the macula in 15-30% of cases
What are the signs of CRAO? (fundoscopy)
- Relative afferent pupillary defect - asymmetrical pupillary reaction to light due to optic nerve disease
- Pale retina
- Cherry red spot = macular sparing due to choroid maintaining blood supply
- Retinal emboli
What is the management of CRAO?
- Intra arterial thrombolysis - limited evidence
- Treat underlying causes eg. IV steroids for temporal arteritis
What are the complications of CRAO?
- Profound visual loss
- Cardiovascular disease burden, more likely to die from stroke
- Neovascularisation of ischaemic retina = vitreous haemorrhage or occlude ant chamber = glaucoma
What is the difference between CRAO and CRVO?
CRVO is more common than CRAO and has widespread hyperaemia and haemorrhages on fundoscopy = stormy sunset.
What are cataracts and what are the causes?
Opacity in the lens due to denatured protein/loss of crystallin.
Causes - increasing age, trauma, steroids, ant uveitis, radiation
What are the CF of cataracts?
- Blurred vision
- Sensitive to bright lights and glare
- Poor night vision
- Halos around lights
- Polyopia
- Reduction in colour intensity
- Loss of red reflex
- Can see white/grey pupil
- Nystagmus
What is the management of age related cataracts?
Replace the diseased lens:
- Phacoemulsification - break up diseased lens and aspirating the contents, then place a new lens into the remaining lens capsule (most common)
- Extra capsular cataract extraction = remove whole nucleus and aspirate lens cortex then insert rigid lens
What are the complications of cataracts surgery?
- Endophthalamitis - infection of the viterous/aqueous
- Corneal oedema
- Malposition of lens
- Retinal detachment
- Post capsule rupture and opacification
What are the causes of cataracts in children?
- Inherited
- Systemic disease eg. intrauterine rubella, DM, myotonic dystropy craniofacial syndromes
- Idiopathic
- Drugs
- Trauma - penetrating injury, electric shock, blunt trauma
Quite a rare cause of blindness in children.
What are some drugs that cause cataracts?
- Steroids
- Amiodarone
- Phenothiazines
What are the sx of cataracts that affect the subcapsular of the lens?
Near vision affected more than distance
What are the sx of cataracts that affect the nuclear area of the lens?
Colours less well saturated and pt short sighted
What are the sx of cataracts that affect the cortical area of the lens?
Sx worse in the dark when the pupil dilates and exposes more of the cataract.
What is the uveal tract?
Iris - pigmented structure that controls the amount of light entering the eye
Ciliary body - produces aqueous humour and controls the thickness of the lens
Choroid - supplies essential nutrients and is richly vascular, removes waste product and absorbs light passing through retina
Mydriasis
Miosis
Mydriasis - dilation of the pupil, dillator pupillae - low light and sympathetic activation
Miosis - constriction of pupil, sphincter pupillae - lots of light and parasympathetic activation
What is the affect of the following drugs on the size of the pupil?
Tropicamide
Phenylephrine
Pilocarpine
Tropicamide - mydriasis
Phenylephrine - mydriasis
Pilocarpine - miosis
What are the different types of uveitis?
Ant uveitis - inflam of the iris and ciliary body
Post uveitis - inflam of retina and choroid
Panuveitis - inflam of whole uveal tract
What are some causes of ant uveitis?
Autoimmune = ankylosisng spondylitis, idiopathic juvenile arthritis, SLE, IBD, vasculitis esp granulomatosis w polyangitis, reactive arthritis
Infections = herpes, TB, syphilis, HIV
What are the CF of ant uveitis?
- Red eye
- Pain
- Blurred vision
- Photophobia
- Increased watering
- Circum corneal injection
- Irregular pupil due to synechiae
- Keratitic precipitates
What are synechiae? What is the risk of them?
Adhesions between the lens and the iris. Can cause obstruction of passage of aqueous humour (closed angled glaucoma?).
What is the management of ant uveitis?
- Topical steroids to reduce inflammation
- Antimuscarinic eye drops eg. cyclopentalate to prevent post synechiae, dilates pupil
What are the CF of post uveritis?
- Painless blurred vision
- Floaters
- Photopsia - perception of flashes of light
- Fundoscopy = choroiditis = raised pigmented lesions and retinitis = cotton wool spots and haemorrhages
What is retinal detachment?
Separation of the neural retina from the retinal pigment epithelium
What are the two layers of the retina?
- Neural retina - only attached at the optic nerve head
- Retinal pigment epithelium - firmly attached to Bruch’s membrane of the choroid
What are the CF of retinal detachment?
- Painless
- Floaters
- Photopsia
- Reduced visual acuity
- Visual field impairment
What is the danger of retinal detachment?
If detachment progresses to the macular sight may be lost and pt will be blind
What is the management of retinal detachment?
- Vitrectomy = removing and replacing vitreous humour
- Scleral buckling = attached a small band around the eye to push the wall of the eye and retina closer together
- Cryotherapy and laser therapy = sealing the tear in the retina
What are the causes of detached retina?
- Short sightedness
- Operation on the eye eg. cataract surgery
- Eye injury and trauma
- FH
What is a corneal ulcer?
A type of infective keratits where a layer of epithelium has been removed off the cornea. Starts as conjunctivitis and pink eye.
What are the causes of corneal ulcers/keratitis?
- Contact lenses
- Herpes and funal causes
- Bells palsy - eyelids don’t fully close
- Foreign body
- Abrasions to eye surface
- Severe allergic eye disease or dry eyes
What is angle closure glaucoma?
Closing/narrowing of the irido-corneal angle = reduced drainage of aqueous humour causing rising intra ocular pressure.
What are the CF of primary closed angle glaucoma?
- Systemically unwell = nausea and headache
- Severe ocular pain
- Blurred vision and halos around lights
- Fixed, dilated pupil
- Red eye