opthalmology Flashcards
where is aqueous humour produced?
ciliary body
what is the purpose of aqueous humour?
supply nutrients to the cornea and lens
explain the course of aqueous humour
travels from the posterior chamber through the pupil into the anterior chamber then drains out of the anterior chamber through 2 independent pathways
what are the 2 pathways that aqueous humour drains out of the anterior chamber?
trabecular meshwork into canal of Schlemm
uveoscleral pathway
what causes primary open angle glaucoma?
resistance to outflow of aqueous humour through trabecular meshwork, causing IOP to rise
give 5 risk factors for open angle glaucoma
myopia (short sighted)
elderly
ocular hypertension
T2DM
cardiovascular disease
how does open angle glaucoma present?
slow and chronic course
usually affecting both eyes
what is the pattern of vision loss in open angle glaucoma?
initially loss of peripheral vision usually in superior visual field before inferior visual field
what are the clinical findings of open angle glaucoma?
increased IOP
visual field defects
cupped discs on fundoscopy
what is the gold standard investigation to measure IOP?
goldmann applanation tonometer
when is treatment for open angle glaucoma started?
when IOP is >24mmHg
what are the 3 management options for open angle glaucoma?
laser management
medical management
surgical management
what is the first line medical management for open angle glaucoma?
prostaglandin analogues e.g. latanoprost
what are the 2 side effects of prostaglandin analogues used in the treatment of open angle glaucoma?
eyelash growth
eyelid and iris pigmentation
aside from prostaglandin analogues, what other medications are used in the treatment of open angle glaucoma?
beta blockers (timolol)
parasympathetics (pilocarpine)
carbonic anhydrase inhibitors (acetazolamide)
what is the surgical management of open angle glaucoma?
trabeculectomy w/ pharmacological augmentation w/ mitomycin C
what is acute angle close glaucoma?
an acute rise in IOP assoc w/ narrowing of anterior chamber angle causing optic nerve damage and sight loss
what is the anterior chamber angle?
the angle between the iris and cornea
what causes acute angle closure glaucoma?
reduced drainage of aqueous humour due to anterior chamber angle narrowing
what are the risk factors for acute angle closure glaucoma?
hypermetropia (long sighted)
age
female (3x more likely than males)
FHx
what is the timeline of acute angle closure glaucoma?
symptoms develop over hours to days
what are the typical symptoms of acute angle closure glaucoma?
unilateral severe eye pain or headache that may cause nausea and vomiting
profound reduction in visual acuity or vision loss
rainbow coloured haloes around bright lights
what are the clinical examination findings of acute angle closure glaucoma?
painful red eye
hazy cornea
fixed, non reactive, mid dilated pupil
v high IOP causing eye to be hard on palpation
what are the 2 investigations for acute angle closure glaucoma?
gonioscopy
tonometry
what is gonioscopy?
the gold standard for investigating the angle between the iris and cornea
mandatory in establishing diagnosis of angle closure glaucoma
what is the gold standard way to measure IOP?
Goldmann applanation tonometry
why is acute angle closure glaucoma an ophthalmic emergency?
because it is sight threatening
what are the conservative measures in the management of acute angle closure glaucoma?
anti emetics
analgesic
lie the pt flat
what are the specialist measures in the management of acute angle closure glaucoma?
systemic pressure reducing agents - acetazolamide
topical pressure reducing agents - beta blockers
topical steroids
peripheral iridotomy
what is a peripheral iridotomy?
a laser hole through the iris to allow a separate route for aqueous drainage
done in the management of acute angle closure glaucoma
