Ophthalmology Flashcards
What is Presbyopia?
eye has reduced ability to focus on near objects because of age
What is hypermetropia?
long sightedness
What is myopia?
short sightedness
Which muscles are innervated by the occulomotor nerve?
Medial rectus
inferior rectus
superior rectus
inferior oblique
Which muscle is innervated by abducent nerve?
Lateral rectus
What muscle is innervated by trochlear nerve?
superior oblique
What is a third nerve palsy?
it is caused by an aneurysm which affect the occulomotor nerve. It causes fixed, mid-dilated pupil and ptosis
What causes a 6th nerve palsy?
Increased intracranial pressure
What are the signs of a 6th nerve palsy?
diplopia, patient sits with head tilted down, failure of eye to abduct on downward gaze
Which direction does the eye move by the superior oblique muscle?
inferomedially (down and in)
Which direction does the eye move by the inferior oblique muscle?
superiomedially (up and in)
What is the cornea?
The clear, transparent part of the eye that covers the iris, pupil and anterior chamber and provides most of the eyes optical power (too flat: hyperopia, too steep: myopia)
What is the function of the anterior chamber?
filled with aqueous humour which fills the space between the back surface of the cornea and the font surface of the vitreous bathing the lens. The function is to nourish the lens, cornea and iris and removing waste products. It also maintains intraocular pressure
How does the pupil become constricted?
It occurs when the pupil size is reduced to constriction of the iris sphincter or relaxation of the iris dilator muscle
What is the triad of Horner’s syndrome?
Miosis, ptosis and enopthalmos
Which eye condition is linked to red desaturation?
Optic neuritis
What is entropion?
in turning of the eyelids
What is ectropion?
out turning of the eyelids
What is the treatment for herpes zoster opthalmicus?
oral aciclovir
What is the most common cause of watery eye in children?
Nasolacrimal duct obstruction
What would a pale retina be indicative of?
Central retinal artery occlusion
What is the first line treatment for primary angle open glaucoma?
Prostaglandin analogs such as latanoprost
What is the mechanism of action of prostaglandin analogs?
They increase uveoscleral outflow
What is the ciliary body?
tissue between the choroids and the iris that is involved in intraocular pressure and lens shape
Where are cones found?
the fovea of the macula
What is the macula?
it is the area of acute central vision
What are the outer layers of the eye?
Retina -> choroid ->sclera (outermost)
What produces aqueous humour?
The ciliary body
Where does aqueous humour drain?
The trabecular meshwork situated in the angle between the iris and the cornea into the canal of schlemm
What is normal intraocular pressure?
<21mmHg
What are direct and consensual responses?
light being shone into an eye will cause constriction (direct) as well as constriction of the other eye (consensual)
What does parasympathetic innervation do to the pupil size?
Constriction
What kind of drug is pilocarpine and how does it work?
it is a miotic that constricts the pupil
What kind of drug is Atropine?
It is a mydriatic and causes dilation of the pupil
What are causes of sudden visual loss?
VARICOSE Vascular occlusion/vitreous haemorrhage] Age related macular degeneration (wet) Retinal detachment Ischaemic optic neuropathy Closed angle glaucoma Optic neuritis Stroke
What is Wet macular degeneration?
it is sudden painless loss of vision with new blood vessels growing under the retina- leakage causes fluid to build up which leads to scarring
How does wet ARMD affect sight?
there is blurred central vision which becomes worse over time as cones degenerate, metamorphopsia (straight lines look wavy)
What is the treatment for wet ARMD?
Anti-VEGF
What is indicative of flashes and floaters?
Retinal detachment
What are the features of central retinal artery occlusion?
pale retina, cherry red spot, engorged vessels, painless, sudden loss of vision
What is the treatment of central retinal artery occlusion?
ocular massage (to convert CRAO to BRAO- less severe)
How does central retinal vein occlusion present?
Severe retinal haemorrhages that gives a stormy sky appearance on fundoscopy. It presents with sudden, painless loss of vision often on waking
What is the cause of acute closed angle glaucoma?
raise in IOP due to closure of the angle between the iris and cornea which can damage the optic disc
Does acute closed angled glaucoma typically occur in the long or short sighted?
longsided
What is halo around the eyes indicative of?
closed angle glaucoma
Is glaucoma painful?
yes- very painful
What are the symptoms of acute closed angled glaucoma?
unilateral acute onset of red painful eye, headache, nausea and vomiting, clouding of the cornea, pupil is fixed and mid-dilated
What is the treatment of acute closed angled glaucoma?
IV acetazolamide, pilocarpine and topical steroids
What is optic neuritis?
inflammation of the optic nerve
What are the symptoms of optic neuritis?
eye pain which is worse on moving the eye and colour desaturation
What is the treatment for optic neuritis?
methylprednisolone
What are the causes of gradual visual loss?
CARDIGAN Cataracts ARMD (dry) Refractive error Diabetic retinopathy inherited disease Glaucoma
What are the symptoms of cataract?
cloudiness of the lens, loss of red reflex, loss of colour contrast
What is the management of cataracts?
Pharmacoemulsification of the lens with insertion of the intra-ocular lens
What would the presence of drusen on fundoscopy be indicative of?
Dry ARMD
What is Dry ARMD?
damage to the cells of the macula as a result of build up of waste product called drusen
What is the treatment for Dry ARMD?
there is no treatment
What is the difference between proliferative and non-proliferative diabetic retinopathy?
neovascularisation signals proliferative
What would be seen on fundoscopy in pre-prepoliferative diabetic retinopathy?
cotton wool spots, hard exudates, dot, blot and flame haemorrhages
What is the treatment for diabetic retinopathy?
photocoagulation
What are the symptoms of Chronic open angle glaucoma?
loss of peripheral vision over time
What is the cause of chronic open angle glaucoma?
Myopia, old age, diabetic- damage to the optic nerve from increased IOP
What is the treatment of chronic open angle glaucoma?
Prostaglandin analogue e.g. latanoprost, beta blockers, carbonic anhydrase inhibitors e.g. Dorzolamide
What is the mechanism of carbonic anhydrase inhibitors?
Reduce IOP by reducing the fluid level in the eye
What is described as a curtain coming down for less than 5 minutes?
Amaurosis fugax
What is uveitis?
inflammation of the uvea (iris, cillary body, choroid)
What is chororetinitis?
It is a form of posterior uveitis and is associated with cytomegalovirus and toxoplasmosis
What are the causes of uveitis?
HLA-B27 (reiters), infective (syphillis, herpes zoster, herpes simplex)
What causes pain, photophobia and a red eye?
uveitis
What is hypopyon and what condition is it related to?
yellow exudate of inflammatory cells in the lower part of the anterior chamber - linked to anterior uveitis
What is the treatment of anterior uveitis?
corticosteroid eye drops, corticosteroid injection
What are the common causes of conjunctivitis in babies?
Chlamydia trachomatis, Neisseria gonorrhoea
What are the features of conjunctivitis?
Acute onset of red gritty eyes with purulent discharge that causes the eyes to stick together
What is the treatment of conjunctivitis?
topical chloramphenicol
What are the side effects of chloramphenicol?
grey baby
What is the difference between bacterial and viral conjunctivitis?
bacteria- sticky eye, more likely to spread
Virus- watery eye, pain on movement
What is keratitis?
inflammation of the cornea
What can be caused by viral keratitis?
HSV can cause dendritic ulcers- appears green on fluroscein staining
What are the symptoms of Keratitis?
needle like pain, photophobia, reduced visual acuity, epiphora (excess lacrimation)
What is the treatment for keratitis?
ofloxacin eye drops, gentamicin, steroids
What is endophthalmitis?
inflammation of the intraocular space occupied by the vitreous
What are the causes of endophthalmitis?
staph epidermidis, after cataract surgery, injury, contact lenses