Ophthalmology Flashcards
What is open angle glaucoma?
it is damage to the optic nerve due to raised IOP leading a blockage of the aqueous humour leaving the eye
rise of IOP over 21mmHg leads to increase in resistance and further pressure - chronic
acute - iris bulges and seals off the meshwork
what is the normal role of the aqueous humour?
it supplies the nutrients to the cornea - made by the ciliary body
flows from CB around the lens and under the iris, through the anterior chamber and into canal of schlem which enters circulation
what are the risk factors for open angle glaucoma?
increasing age, FHx, black, myopia
how does open angle glaucoma affect the optic disc?
it causes cupping
how does open angle glaucoma present?
can be asymptomatic for a long time - routine screening picks it up
affect peripheral vision first resulting in tunnel vision, gradual onset fluctuating pain, headaches, blurred vision and haloes at night
how is open angle glaucoma investigated?
air puff or Goldmann applanation tonometry, fundoscopy, visual field assessment
how is open angle glaucoma managed?
management starts at 24mmHg
prostaglandin eye drops such as lantaprost to increase outflow
BB to reduce production
carbonic anhydrase inhibitors to reduce production
sympathomimetics
trabeculectomy
what is the pathophysiology of acute angle closure glaucoma?
the iris bulges forwards and seals off the trabecular network from anterior chamber so the aqueous humour cannot escape
what are the risk factors for acute AC glaucoma?
increasing age, female, FHx, chinese, east asian, shallow anterior chamber, drugs
how does acute AC glaucoma present?
unwell, severely painful red eye, blurred vision, haloes, headache, N+V
red teary eye
hazy cornea
decreased VA
dilatation of the affected pupil
fixed pupil size
firm eyeball on palpation
how is acute AC glaucoma managed?
initially - lie on back, pilocarpine eye drops, acetazolamide, analgesia, antiemetics
secondary care - pilocarpine, acetazolamide, hyperosmotic agents, timolol, dorzolamide, brimonidine, laser iridotomy
what is diabetic retinopathy?
it is when the retinal vessels are damaged due to chronic hyperglycaemia, this damage causes hard exudates, blot haemorrhages, microaneurysms, cotton wool spots, intraretinal microvascular abnormalities, neovasculariation
what is the difference between proliferative and non proliferative diabetic retinopathy?
proliferative - neovascularisation and vitreous haemorrhage
non - mild, moderate and severe all signs except neovascularisation
what is diabetic maculopathy?
it is macular oedema and ischaemia maculopathy
how is diabetic retinopathy managed?
laser photocoagulation, antiVEGF, vitreoretinal surgery
what are complications of diabetic retinopathy?
retinal detachment, vitreous haemorrhage, rebeosis iridis, optic neuropathy, cataracts
what is ARMD?
it is macular degeneration that can be wet (10%) or dry (90%)
results in drusen, atrophy of retinal pigment epithelium, degeneration of photoreceptors
what is wet ARMD?
it is new vessels from choroid layer into retina, which then leaks, results in oedema and more visual loss - stimulated by VEGF
how is ARMD investigated?
decreased VA, scotoma, Amsler grid testing, drusen on fundoscopy, slit lamp biomicroscopic fundus exam, optical coherences tomography, fluroescein angiography
how does ARMD present?
gradual worsening central vision, decreased acuity, crooked or wavy appearance to straight lines, more acute if wet
how is ARMD managed?
avoid smoking, control BP, vitamin supplementation
wet - antiVEGF monthly
what controls pupil constriction and dilatation?
circular muscles in iris controlled by PNS through oculomotor control - constriction
dilatation - dilator muscles are stimulated by SNS using adrenalin
what can result in an abnormal shaped pupil?
trauma, anterior uveitis, acute ACG, rubeosis iridis
what causes mydriasis?
third nerve palsy, Holmes Adie syndrome, increased ICP, trauma, congenital, stimulants, anticholinergics
summarise Horners?
it is ptosis, miosis, enopthalmos and anhidrosis
causes - stroke, MS, syringomyelia, tumour, trauma, thyroidectomy, carotid artery dissection, cavernous sinus thrombosis, cluster headaches
ix - cocaine drops give no response, adrenalin drops will dilate horners pupil but not a normal pupils
what can cause miosis?
horners, cluster headaches, opiates, nicotine, Argyll Robertson pupil
summarise CNIII palsy?
ptosis, non reactive dilated pupil, divergent strabismus
idiopathic, DM, HTN, ischaemia, ICP, tumour, trauma
what is Holmes Adie puil?
unilateral dilated pupil with sluggish reaction to light that gets smaller over time
absent knee and ankle reflexes - HA syndrome
can be viral cause
what is a Argyll Robertson pupil?
neurosyphilis - accommodates to near object but not light, irregular and constricted
summarise belpharitis?
inflammation of the eyelid margins
gritty, itchy, dry eye
can lead to styes and chalzions
mx - hot compress, lubricant eye drops, keep clean
summarise stye?
externum is glands of Zeus or Moll
internum is Meibomian
tender red lump on eye lid
mx - analgesia, hot compress, topical ABx if required
summarise trichiasis?
inward eyelash growth - corneal damage and ulceration
mx - epilation, electrolysis, cryotherapy, laser