Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Ophthalmology > 10. Pharmacology, Microbiology, Cataract > Flashcards

10. Pharmacology, Microbiology, Cataract Flashcards

1
Q

What are considered to be commensal organisms of the eyelid and conjunctiva?

A

Staph epidermidis
Staph aureus

  • Not usually responsible for serious pathology?
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are common pathological organisms for the eyelid/conjunctiva?

A
  • Gram +ive (staph, strep)
  • Gram –ive (pseudomonas, e. Coli, klebsiella)
  • Viruses (adenovirus, herpes)
  • Protozoa (acanthomoeba) (serious lens infections)
  • Fungi
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What are the defense mechanisms of the cornea?

A
  • Intact epithelium
  • Irrigation by tears
  • Tear lysozyme
  • Blinking
  • Decreased ocular temperature
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are common pathologies which compromise corneal defenses?

A

Corneal abrasion,
Contact lenses,
Ocular surgery

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What pathologies often result from compromised corneal defenses?

A

Conjunctivitis
Keratitis
Endophthalmitis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are the main methods of administration for ocular medications?

A
  1. Topical (eye drops)
  2. Systemic (oral, IV)
  3. Periocular (peribulbar, rebrobulbar, subtenons)
  4. Intraocular (intravitreal)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are the features of topical administration?

A

Good for delivering local antibiotics, steroids.

Lipid soluble for better penetration

Especially good for anterior chamber problems.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What are the features of systemic administration?

A

Good for Uveitis, GCA etc

eg steroids, antibiotics, acetazolamide.

Carbonic Anhydrase in AACG

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What are the features of periocular administration?

A

(peribulbar, retrobulbar, subtenons) –

eg local anaesthetic, steroid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are the features of intraocular administration?

A

(intravitreal) – eg intravitreal anti-

VEGF, antibiotics

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What causes miosis?

A 
Parasympathetic NS 
From EWN
Via Inferior Division of CNIII
To Ciliary Ganglion
To Short Ciliary Nerves

Innervates iris sphincter = Miosis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What causes mydriasis?

A 
Sympathetic NS
From Hypothalamus
Via Superior Cervical Ganglion
To Cavernous Sinus Ophthalmic Division of CN V (Trig)
To Nasociliary Nerve
To long Ciliary Nerve

Innervates iris dilator = mydriasis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Give examples of dilating drops?

A
  1. Antimuscarinics
    - tropicamide, cyclopentolate, atropine
  2. Alpha-agonists
    – phenylephrine
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Give some uses of dilating eye drops?

A

Uses –
to facilitate examination,
therapeutic (useful in uveitis, hyphaema)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Give examples of constricting drops

A

Parasympathomimetic

– pilocarpine (muscarinic receptor agonist)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Give some uses of constricting drops?

A

Uses

– lowering IOP, acute angle closure glaucoma

17
Q

Examples of Topical Anaesthetics?

A

Proxymethacaine, tetracaine

18
Q

What are the potential S/E’ of topical anaesthetic? When are they indicated?

A

Warning: Can impair corneal healing.

Only used for purpose of examination. Do not prescribe.

19
Q

Antibiotics used for conjunctivitis?

A

Chloramphenicol

Fucidic acid

20
Q

Antibiotics used for Pseudomonal Inf (corneal lens inf)?

A

Ofloxacin/Floxin

21
Q

Antibiotics for more severe infections eg severe bacterial keratitis, endophthalmitis?

A

Cephalosporins
Vancomycin
Gentamycin

22
Q

Steroids used in treatment of ocular inflammatory conditions?

A

Prednisolone

Dexamethasone

23
Q

Rx in allergic conjunctivitis?

A

Antihistamines

Mast cell stabilisers

24
Q

What are the Rx’s in glaucoma?

A

Protaglandin analogues
• Increase aqueous outflow
• Risk of increased eyelash/iris pigmentation

Beta-blockers
• Reduce aqueous production
• Risk of bronchospasm in susceptible patients (avoid in asthma, CCF)

Carbonic anhydrase inhibitors
• Acetazolamide or topical versions
• Reduce aqueous production

Alpha-agonists
• Reduce aqueous production, increase outflow
• Can cause red eye

25
Q

Which commonly used drugs have occular side effects? What are they?

A
  • Steroids (increased IOP)– glaucoma, cataract
  • Ethambutol, quinine (TB) – optic neuropathy
  • Chloroquine (Antimalarial) – maculopathy
  • Tamoxifen – pigmentary retinopathy
  • Vigabitrin – visual field defects
  • Amiodarone – Corneal deposits (vortex keratopathy)
26
Q

What is Cataract?

A

Loss of transparency of the lens

27
Q

What are the symptoms of cataract?

A

Gradual reduction in visual acuity

“a cloud”, “generalised blur”, “haze”,
“everything duller”
“Glare” from bright lights, sunshine – difficulty driving at night – glare from oncoming cars

Myopic shift – Induced Myopia

28
Q

What are the clinical findings in cataracts?

A

Reduced visual acuity – which may improve with pinhole

Diminished red reflex (clouding)

NO RAPD (provided retina and optic nerve are healthy)

Note: As a cataract becomes very mature it become fatter, and can push the iris forward thus narrowing the
iridocorneal angle, which can predispose to angle closure.
glaucoma and high IOP

29
Q

Common misconceptions about Cataract?

A 
A cataract is NOT:
• A film over the eye
• Spread from one eye to the other
• Caused by straining the eye
• A cause of irreversible blindness
• Is not fixed by laser (although newer techniques for cataract extraction do involve lasers – still intraocular)
30
Q

What are the different types of cataracts?

A

Nuclear Sclerosis (most common)
Cortical
Posterior Sub capsular

31
Q

What are the risk factors for cataracts?

A

• AGE
• Diabetes
• Family history
• Previous surgery or injury to the eye
• Certain medications, prolonged use of steroids
• Congenital cataracts associated with intrauterine
infections – rubella, toxo, CMV, herpes
• Associated with certain syndromes – myotonic dystrophy,
Down’s

32
Q

What are the indications for surgery in cataracts?

A
  1. Operate for visual improvement
    – when patient complains of difficulty seeing, performing daily tasks, reading, driving
  2. Operate for medical reasons
    – eg to improve view of fundus for monitoring diabetic retinopathy, to help treat high IOP.
33
Q

Describe Cataract surgery? Efficacy? Risks?

A

Local anaesthetic for most cases (topical only, peribulbar, subtenons)

GA – for patients who can’t lie still, young, very anxious

Approx 20 minute procedure

90-95% chance of good-excellent vision post-op

2% chance of vision not improving much or deteriorating

1 in 1000 risk of vision loss (eg due to endophthalmitis)

34
Q

What are the potential complications of Cataract Surgery?

A

Intraoperative:
• Rupture or tear of posterior capsule – the “bag”
• This means that vitreous could come forward; lens fragment could fall into posterior segment; ruptured “bag” can’t hold new lens implant – may need to put it into anterior chamber

Postoperative
• Increased IOP
• Corneal oedema
• Macular oedema
• Retinal detachment (higher risk in myopes)
• Induced astigmatism from wound
• Serious infection (endophthalmitis) – risk 1 in 1000

35
Q

How is the risk of infection post-operative infection mitigated?

A
  1. Antiseptic – betadine (Broad spectrum microbicidal
    Activity)
  2. Intraoperative antibiotic
    - 3rd gen cephalosporin, gentamycin (broad spectrum
    spectrum – gram pos, gram neg, pseudomonas)
  3. Postoperative antibiotic
    – chloramphenicol, neomycin
  4. Postoperative steroid
    – dexamethasone

Ophthalmology (10 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions