Ophthalmology

Question 1

Most common intraoperative complication in cataract surgery?

Answer 1

Posterior capsular rupture with vitreous loss

Question 2

Floppy iris syndrome

Answer 2

the iris is flaccid
complicates surgery because it gets in the way of the operation and isn’t fixed into position
A/w alpha blockers e.g. tamsulosin

Question 3

4 main intraoperative complications which occur during cataract surgery…

Answer 3

Choroidal haemorrhage (ophthalmologist’s worst nightmare!)
Posterior capsular rupture with vitreous loss
Zonular dehiscence
Dropped Nucleus

Question 4

2nd Leading cause of blindness worldwide

Answer 4

Glaucoma

Question 5

Prostaglandin agonists MOA and S/Es

Answer 5

e.g. Latanoprost
- Increases uveoscleral outflow
- Iris pigmentation
- Eyelash growth
- Hyperaemia
- Uveitis
- Macular oedema

Question 6

Beta Blockers

Answer 6

e.g. Timolol
- Decreases aqueous humour production by blocking adrenergic cAMP
- Carteolol doesn’t causes many side effects due to its intrinsic sympathomimetic properties
- Betaxolol is a selective Beta 1 blocker
- Bradycardia and worsens asthma
Contraindicated in Breastfeeding and lung and heart conditions

Question 7

Alpha 2 agonists

Answer 7

• Decreases uveoscleral outflow and aqueous humour production
• Brimonidine is a alpha 2 rec blocker
• Apraclonidine is a alpha 1 and 2 blocker

Question 8

Cholinergic agonists

Answer 8

e.g. Pilocarpine
- Ciliary contraction ->opens TM -> increases TM outflow
- causes miosis which relieves pupil block
- polyuria, diarrhoea, salivation, lacrimation, sweating

Question 9

Carbonic anhydrase inhibitors

Answer 9

e.g. brinzolamide
- Inhibit anhydrase isoenzyme II → reduce aqueous production
- Oral (acetazolamide) is more effective because it also blocks isoenzyme IV
- Hypokalemia, Metabolic acidosis

Question 10

Peripheral iridoplasty. Indication, Laser used and how does it work?

Answer 10

Temporising measure in acute angle-closure
Argon 455mm - 529mm
contraction burns of the peripheral iris pull it away from the angle

Question 11

Peripheral iridotomy . Indication, Laser used and how does it work?

Answer 11

Definitive management of acute angle closure glaucoma
ND:YAG 1064mm
creates a hole in the peripheral iris to allow aqueous flow through a closed-angle

Question 12

Selective laser trabeculoplasty (SLT). Indication, Laser used and how does it work?

Answer 12

Used in open-angle glaucoma where medical treatment is not tolerated
Frequency doubled Q switched ND:YAG 532mm
laser applied to the trabecular meshwork to facilitate drainage

Question 13

Commonest primary childhood orbital malignancy

Answer 13

Rhabdomyosarcoma

Question 14

Cystoid Macular Oedema is…
signs?
Tx?

Answer 14

Intraretinal oedema- result of ocular inflammation commonly post-cataract surgery. Can also occur in diabetic retinopathy, uveitis, retinitis pigmentosa and latanoprost use.
- Fluid gathers in the intracellular spaces of the retina most commonly the outer plexiform.
- Results in dVA b/c fluid obstructs light
- Blurry vision, metamorphosis, and scotoma
- Mainstay tx is steroids. if persisting after one month then add infraorbital steroid injections
- after another month, consider intravitreal steroids or systemic.

Question 15

What is Anisocoria?

Answer 15

Unequal sized pupils

Question 16

Fuchs Endothelial Dystrophy

Answer 16

• Elderly woman with bilateral blurry vision worse in morning clearing towards end of day because eyes are open and blinking which helps get rid of fluid accumulation
• Failure of Na-K pump in corneal epithelium leads to fluid accumulation and endothelial cell loss
• beaten metal appearance (corneal guttata)
• NaCl drops and hairdryer application
• DMEK, DSAEK for severe disease

Question 17

Difference between Lambert-Eaton and Myasthenia gravis

Answer 17

Fatigue improves with muscle use in L-E compared to MG which worsens.

Question 18

Horner Syndrome - Causes

Answer 18

First Order: Brain and spinal cord lesions
Second Order: Pancoast tumour and neck trauma
Third Order: No anhidrosis due tot he secretomotor fibres that supply the sweat gland leave the pathway before the third order neutron.
Cavernous sinus lesions and internal carotid dissection

Question 19

Horner Syndrome - Localising the lesion

Answer 19

Topical Apraclonidine and Topical Cocaine used to confirm a diagnosis of Horner’s
Topical Hydroxyamphetamine and Topical cocaine- to distinguish third order lesions from the others (post and pre-ganglionic)
Painful Horner’s Syndrome is a carotid dissection until proven otherwise so get a carotid angiogram.

Question 20

Elevation →
Depression →
Adduction →
Abduction →
Intorsion →
Extorsion →

Answer 20

SR (Primary) + IO
IR (Primary) + SO
MR (Primary) + SR + IR
LR (Primary) + SO + IO
SO
IO

Question 21

Distinguishing between Episcleritis and Scleritis

Answer 21

Topical phenylephrine affects the episclera’s superficial vascular plexus whereas for the sclera it doesn’t because they too deep. Therefore, in episcleritis the reddened vessels blanch on application of the phenylephrine but sclera doesn’t.
Episcleritis is painless but sclera IS painful.
The episclera is between the sclera and conjunctiva.