glaucoma + cataracts

Question 1

glaucoma

Answer 1

raised intraocular pressure caused by resistance of drainage of aqueous humour through the trabecular network / canal of schlemm

Question 2

different fluids in the eye ball and where they’re found

Answer 2

vitreous chamber = vitreous humour

anterior + posterior chamber = aqueous humour
- supplies nutrients to cornea
- produced by ciliary body

Question 3

normal intraocular pressure + pressure criteria for invervention

Answer 3

normal = 10-21 mmHg

treatment offered at 24mmHg

Question 4

open angled glaucoma risk factors

Answer 4

increasing age, FH
black ethnic origin
near-sightedness (myopia)

(slow onset, often asymmtomatic picked up on screening)

Question 5

open angled glaucoma presentation

Answer 5

• affects peripheral vision first - eventually tunnel vision
• gradual onset fluctuating pain
• headaches
• blurred vision

**haloes around lights

Question 6

glaucoma investigations for measuring intraocular pressure

Answer 6

• 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

Question 7

management of open angled glaucoma

Answer 7

• 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

Question 8

eye drop options in Mx of chronic glaucoma

Answer 8

latanoprost (prostaglandin analogue)
timolol (betablocker)
dorzolamide (carbonic anhydrase inhibitors)
brimonidine (sympathomimetics)
pilocarpine (miotics/muscarinic receptor agonist)

Question 9

timolol

Answer 9

 reduce production of aqueous humour
 avoid in asthmatics + those with heart failure

Question 10

Dorzolamide

Answer 10

carbonic anhydrase inhibitors

reduce production of aqueous humour

Question 11

Brimonidine

Answer 11

sympathomimetics –

 reduce production of aqueous fluid + increase uveoscleral outflow
 avoid if taking MAOI or tricyclic antidepressant
 SE – hyperaemia (too much blood)

Question 12

Pilocarpine

Answer 12

miotics/muscarinic receptor agonist

 Increase uveoscleral outflow
 SE – constricted pupil, headache, blurred vision

Question 13

closed angle glaucoma

Answer 13

when iris bulges forward + seals off trabecular meshwork from anterior chamber preventing drainage
- continual increase in pressure

ophthalmic emergency

Question 14

acute closed glaucoma risk factors

Answer 14

• Shallow anterior chamber
• Chinese/east Asian origin
• Female – 4x more than males
• FH
• Increasing age

medications can precipitate !

Question 15

medications which can precipitate closed angle glaucoma

Answer 15

• Adrenergic – noradrenaline
• Anticholinergic – oxybutynin, solifenacin
• Tricyclic antidepressants – amitriptyline (anticholinergic)

Question 16

presentation of closed angle glaucoma

Answer 16

• 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

Question 17

immediate mx of closed angle glaucoma

Answer 17

o Pilocarpine eye drops (2% blue eyes, 4% for brown)
o Acetazolamide 500mg orally
o Analgesia/antiemetic

lie flat on back

Question 18

why is pilocarpine used in the mx of closed angle glaucoma

Answer 18

causes contraction of ciliary muscle -> opening trab meshwork -> increase outflow of aqueous humour

constricts pupil = miotic agent

Question 19

definitive management of clase angled glaucoma

Answer 19

laser peripheral iridotomy

Creates tiny hole in peripheral iris -> relieves pressure pushing iris against cornea, opens pathway for draining

Question 20

presentation of cataracts

Answer 20

v slow reduction in vision
change in colours

“starbursts” around lights
loss of red reflex

Question 21

complication of cataract mx

Answer 21

endophthalmitis - post lens replacement
- inflammation of inner contents of eye
Tx = intravitreal antibiotics, injected in