Ophthalmology Flashcards
Most common intraoperative complication in cataract surgery?
Posterior capsular rupture with vitreous loss
Floppy iris syndrome
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
4 main intraoperative complications which occur during cataract surgery…
Choroidal haemorrhage (ophthalmologist’s worst nightmare!)
Posterior capsular rupture with vitreous loss
Zonular dehiscence
Dropped Nucleus
2nd Leading cause of blindness worldwide
Glaucoma
Prostaglandin agonists MOA and S/Es
e.g. Latanoprost
- Increases uveoscleral outflow
- Iris pigmentation
- Eyelash growth
- Hyperaemia
- Uveitis
- Macular oedema
Beta Blockers
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
Alpha 2 agonists
- Decreases uveoscleral outflow and aqueous humour production
- Brimonidine is a alpha 2 rec blocker
- Apraclonidine is a alpha 1 and 2 blocker
Cholinergic agonists
e.g. Pilocarpine
- Ciliary contraction ->opens TM -> increases TM outflow
- causes miosis which relieves pupil block
- polyuria, diarrhoea, salivation, lacrimation, sweating
Carbonic anhydrase inhibitors
e.g. brinzolamide
- Inhibit anhydrase isoenzyme II → reduce aqueous production
- Oral (acetazolamide) is more effective because it also blocks isoenzyme IV
- Hypokalemia, Metabolic acidosis
Peripheral iridoplasty. Indication, Laser used and how does it work?
Temporising measure in acute angle-closure
Argon 455mm - 529mm
contraction burns of the peripheral iris pull it away from the angle
Peripheral iridotomy . Indication, Laser used and how does it work?
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
Selective laser trabeculoplasty (SLT). Indication, Laser used and how does it work?
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
Commonest primary childhood orbital malignancy
Rhabdomyosarcoma
Cystoid Macular Oedema is…
signs?
Tx?
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.
What is Anisocoria?
Unequal sized pupils
Fuchs Endothelial Dystrophy
- 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
Difference between Lambert-Eaton and Myasthenia gravis
Fatigue improves with muscle use in L-E compared to MG which worsens.
Horner Syndrome - Causes
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
Horner Syndrome - Localising the lesion
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.
Elevation →
Depression →
Adduction →
Abduction →
Intorsion →
Extorsion →
SR (Primary) + IO
IR (Primary) + SO
MR (Primary) + SR + IR
LR (Primary) + SO + IO
SO
IO
Distinguishing between Episcleritis and Scleritis
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.
