Ophthalmology Flashcards
what is the pathophysiology of acute angle closure glaucoma?
iris bulges forwards and seals off trabecular meshwork of anterior chamber, preventing aqueous humour from draining leading to increase in intraocular pressure => leads to further bulging of iris exacerbating angle closure
what are 6 risk factors for acute closed angle glaucoma?
Increased age
FHx
Female - 4x than M
Chinese/east asian ethnic origin
shallow anterior chamber
Hypermetropia - long sightedness
what are 3 meds that can precipitate acute closed angle glaucoma?
Adrenergic medications - noradrenaline
Anticholinergic meds - oxybutynin, solfenacin
Tricyclic antidepressants - amitryptyline
what are 5 presentations of acute closed angle glaucoma?
severe painful red eye
blurred vision
Halos around lights
Headache, nausea and vom
Pain worse on pupil dilation - watching TV in dark room
what are 5 signs of acute closed angle glaucoma on examination?
Red eye
Hazy cornea
decreased visual acuity
mid-dilated fixed size pupil
Hard eyeball on gentle palpation
what is the initial management of acute closed angle glaucoma in primary care? (4)
Lie patient on back without pillow
Pilocarpine eyedrops - 2% for blue eyes, 4% for brown eyes
Acetazolamide 500mg orally
Analgesia + antiemetics
WHAT IS PILOCARPINE?
direct parasympathomimetic
used in management of acute closed angle glaucoma
acts on muscarinic receptors in sphincter muscle of iris causing pupil constriction (miotic agent) as well as causing ciliary muscle contraction
OPens pathway for flow of aqueous humour from ciliary body into trabecular meshwork
what is acetazolamide?
Used in treatment of acute closed angle glaucoma
carbonic anhydrase inhibitor - reduces production of aqueous humour
what is the dose of pilocarpine in blue eyes in acute closed angle glaucoma?
2%
what is the dose of pilocarpine in brown eyes in acute closed angle glaucoma?
4%
what is the dose of acetazolamide in acute closed angle glaucoma?
500mg PO
what is the definitive treatment of acute closed angle glaucoma?
laser iridotomy - making hole in iris with laser to allow for aqueous humour to drain from posterior to anterior chamber, relieving pressure
what are 6 secondary care options for management of acute closed angle glaucoma?
1 - Drops - pilocarpine, timolol, apraclonidine
1 - Acetazolamide - PO or IV
Definitive - laser peripheral iridotomy
Hyperosmotic agents - mannitol to increase osmotic gradient between blood and eye
Timolol - B Blocker which reduces production of aqueous humour
Dorzolamide - carbonic anhydrase inhibitor
Brimonidine - sympathomimetic that reduces aqueous humour production and increased uveoscleral outflow
what are 2 investigations for acute closed angle glaucoma?
Tonometry for elevated IOP
Gonioscopy - looking at angle
what is blepharitis?
inflammation of the eyelid margins
can be associated with dysfunction of meibomian glands or seborrhoeic dermatitis - can lead to styes, chalazions and conjunctavitis
what is the presentation of blepharitis?
bilateral, gritty, itchy, dry sensation in eyes worse in morning
Eyes may feel sticky in morning
Eyelid margins may be red/swollen
what is the management of blepharitis?
hot compress BD
Lid hygiene with cotton wool dipped in cooled boiled water
Artificial tears for symptom relief
what are the 2 different types of stye?
Hordeolum externum - infection of the glands of zeis or glands of moll - sebaceous or sweat glands at base of eyelashes - tender red possibly pussy lump at base of eyelashes
Hordeolum internum - infection of meibomian glands - deeper more painful, may point inwards towards eyeball underneath eyelid
what is the management of styes?
hot compress
analgesia
Chloramphenicol - topical ABx - may be considered with coexisting conjunctivitis
what is a chalazion?
blocked and swollen meibomian gland also called meibomian cyst
usually non-tender swelling of eyelid
what is the management of a chalazion
warm compress and gentle massage towards eyelashes to encourage drainage
rarely needs surgical drainage
what is entropion?
when the eyelid turns inwards and the eyelashes press on the eye
can cause corneal damage and ulceration
what is the management of entropion?
surgery
should have same day referral to ophthalmology if risk to sight
what is an eye ectropian?
when eyelid turns outwards exposing inner aspect