glaucoma + cataracts Flashcards
glaucoma
raised intraocular pressure caused by resistance of drainage of aqueous humour through the trabecular network / canal of schlemm
different fluids in the eye ball and where they’re found
vitreous chamber = vitreous humour
anterior + posterior chamber = aqueous humour
- supplies nutrients to cornea
- produced by ciliary body
normal intraocular pressure + pressure criteria for invervention
normal = 10-21 mmHg
treatment offered at 24mmHg
open angled glaucoma risk factors
increasing age, FH
black ethnic origin
near-sightedness (myopia)
(slow onset, often asymmtomatic picked up on screening)
open angled glaucoma presentation
- affects peripheral vision first - eventually tunnel vision
- gradual onset fluctuating pain
- headaches
- blurred vision
**haloes around lights
glaucoma investigations for measuring intraocular pressure
- Non-contact tonometry
o Puff of air at cornea, measures it response
o Used for screening - Goldmann applanation tonometry = GOLD standard
o Device mounted on slit lamp
Gonioscopy = lens for slit lamp that allows visualization of the angle
management of open angled glaucoma
- 1st line = 360’ selective laser trabeculoplasty
o Can delay need for eye drops
o Laser the trab meshwork, improving drainage
o A second procedure may be required at later date - Latanoprost (prostaglandin analogue) first line medical mx
o Increase uveoscleral outflow
o SE – eyelash growth, eyelid + iris pigmentation (browning)
trabeculectomy - if other mx ineffective, create new channel from anterior chamber through sclera -> creating bleb
eye drop options in Mx of chronic glaucoma
latanoprost (prostaglandin analogue)
timolol (betablocker)
dorzolamide (carbonic anhydrase inhibitors)
brimonidine (sympathomimetics)
pilocarpine (miotics/muscarinic receptor agonist)
timolol
reduce production of aqueous humour
avoid in asthmatics + those with heart failure
Dorzolamide
carbonic anhydrase inhibitors
reduce production of aqueous humour
Brimonidine
sympathomimetics –
reduce production of aqueous fluid + increase uveoscleral outflow
avoid if taking MAOI or tricyclic antidepressant
SE – hyperaemia (too much blood)
Pilocarpine
miotics/muscarinic receptor agonist
Increase uveoscleral outflow
SE – constricted pupil, headache, blurred vision
closed angle glaucoma
when iris bulges forward + seals off trabecular meshwork from anterior chamber preventing drainage
- continual increase in pressure
ophthalmic emergency
acute closed glaucoma risk factors
- Shallow anterior chamber
- Chinese/east Asian origin
- Female – 4x more than males
- FH
- Increasing age
medications can precipitate !
medications which can precipitate closed angle glaucoma
- Adrenergic – noradrenaline
- Anticholinergic – oxybutynin, solifenacin
- Tricyclic antidepressants – amitriptyline (anticholinergic)
presentation of closed angle glaucoma
- Generally unwell + short history of –
o Severe painful red eye
o Blurred vision
o Halo around lights
o Assoc headache, N+V
Examination
- Hazy cornea
- Dilation of affected eye, fixed pupil size
- Red eyes, teary
- Decreased visual acuity
- Firm eyeball on palpation
immediate mx of closed angle glaucoma
o Pilocarpine eye drops (2% blue eyes, 4% for brown)
o Acetazolamide 500mg orally
o Analgesia/antiemetic
lie flat on back
why is pilocarpine used in the mx of closed angle glaucoma
causes contraction of ciliary muscle -> opening trab meshwork -> increase outflow of aqueous humour
constricts pupil = miotic agent
definitive management of clase angled glaucoma
laser peripheral iridotomy
Creates tiny hole in peripheral iris -> relieves pressure pushing iris against cornea, opens pathway for draining
presentation of cataracts
v slow reduction in vision
change in colours
“starbursts” around lights
loss of red reflex
complication of cataract mx
endophthalmitis - post lens replacement
- inflammation of inner contents of eye
Tx = intravitreal antibiotics, injected in
