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Clinical - Winter > 24 - Glaucoma > Flashcards

24 - Glaucoma Flashcards

1
Q

What are the main risk factors for glaucoma?

A
  • High intraocular pressure (greater than 30 mmHg)
  • Aging
  • Family history (primary relative)
  • Race (black and Hispanic)
  • Optic disc appearance
  • Corneal thickness greater than 0.5 mm
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2
Q

What is used to diagnose glaucoma?

A

Optic disc appearance

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3
Q

What is the normal intraocular pressure? What is considered high intraocular pressure?

A
  • Normal = 10-21 mmHg
  • Pressure over 21 mmHg doesn’t mean it is a problem, so no real definition of high IOP
  • General rule = if glaucomatous damage, lower the IOP
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4
Q

Intraocular pressure is due to _____

A

Balance of aqueous humor

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5
Q

Where is aqueous humor produced? Where is it drained?

A
  • Produced continuously in ciliary body

- Drained into trabecular meshwork (80% into canal of Schlemm and 20% into uveoscleral outflow)

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6
Q

What is the primary defect in open angle glaucoma? What is the tx?

A
  • Primary defect = decreased drainage

- Tx = drainage and/or humor production

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7
Q

What is closed angle glaucoma?

A
  • Ballooning of iris causing decreased aqueous humor flow, increasing pressure
  • Emergency situation
  • Acute drug tx followed by surgery
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8
Q

What are the sx of open angle glaucoma?

A
  • Most people are asymptomatic
  • By the time they see sx, 25-30% of axons of optic nerve are gone
  • Gradually lose ability to see colour and contrast
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9
Q

What are the 2 tx approaches for glaucoma? How is each carried out?

A

1) Decrease production of aqueous humour – target receptors on ciliary body (alpha or beta) or carbonic anhydrase
2) Increase drainage – target trabecular meshwork and canal of schlemm, uveoscleral outflow, or surgery (if drugs don’t produce desired outcome)

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10
Q

Which drugs are parasympathomimetics? What is their effect? What is their dosage? What are some SE? When are they contraindicated?

A
  • Pilocarpine, carbachol
  • Increase outflow of aqueous humour
  • Dose = drops 2-4 times/day; gel for 1 day; inserts for 7 days
  • SE = poor night vision, blurred vision, aching, brow ache (clears after 2-3 weeks), GI, salivation
  • CI when miosis undesirable (ex: iritis), retinal detachment
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11
Q

What are the categories of drugs used for glaucoma?

A

1) Parasympathomimetics (miotics)
2) Sympathomimetics
3) Beta blockers
4) Carbonic anhydrase inhibitors
5) Prostaglandin analogues
6) Hyperosmotic solutions

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12
Q

What is the effect of sympathomimetics? When are they contraindicated?

A
  • Improve outflow (uveoscleral and trabecular meshwork)
  • Acts on alpha and beta adrenoreceptors in ciliary body; increase outflow but may increase aqueous humor production
  • CI in closed angle glaucoma, hypertension and heart disease
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13
Q

Which sympathomimetics are used for glaucoma and when?

A
  • Aproclonidine used post eye surgery

- Brimonidine is most common; lowers IOP w/ minimal systemic effects

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14
Q

What is the first line for glaucoma?

A
  • Beta blockers
  • Specifically timolol, levobunolol, and betaxolol
  • Used in open and closed angle
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15
Q

What is the effect of beta blockers in the eye? When are they contraindicated?

A
  • Decreased aqueous humour production

- CI = heart failure, asthma, COPD, diabetes, heart block, sinus bradycardia

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16
Q

What is the effect of carbonic anhydrase inhibitors in the eye? Which formulation is most commonly used? What are some SE?

A
  • Inhibit bicarbonate formation in ciliary body, so decrease aqueous humour production
  • Topical is most common (brinzolamide and dorzolamide)
  • SE = metabolic acidosis, K+ depletion, fatigue, depression, allergies
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17
Q

What is the effect of prostaglandin analogues in the eye?

A
  • Decrease IOP by increasing uveoscleral outflow
  • Increase outflow by both relaxing ciliary muscle and directly altering extracellular matrix to decrease outflow resistance
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18
Q

Which prostaglandin analogues are used for glaucoma? What are some SE?

A
  • Latanaprost, travoprost, bimatoprost, and tafluprost
  • Topical SE = allergy and conjunctival redness, change iris pigmentation, produce eyelid darkening, increase number, thickness, and pigmentation of eyelashes
  • Systemic SE = skin reaction, chest pain, muscle and joint pain
19
Q

When are hyperosmotic solutions used for glaucoma? When should they be avoided?

A
  • Emergency
  • May be used to decrease pressure pre-op
  • Avoid in severe dehydration, pulmonary edema, and congestive heart failure
20
Q

Which classes of drugs decrease aqueous humour production?

A
  • Beta blockers
  • Alpha 2 agonists (sympathomimetic)
  • Carbonic anhydrase inhibitor
21
Q

Which classes of drugs increase outflow?

A
  • Parasympathomimetics
  • Epinephrine and alpha 2 agonists (sympathomimetics)
  • Prostaglandin analogue
22
Q

What is the tx plan for glaucoma?

A
  • Go w/ beta blocker first
  • If beta blocker CI or ineffective, try monotherapy w/ prostaglandin, local CA inhibitor, or alpha 2 agonist
  • If these ineffective, try combinations of beta blocker + (PG or topical CA inhibtor or miotic) or PG + (CA inhibitor or alpha 2 agonist)
  • Parasympathomimetics are 3rd line b/c of side effects; may be used as miotic w/ PG or beta blocker
23
Q

What is tx goal for primary open angle glaucoma?

A

Lower IOP by 20-30% from baseline

24
Q

Should glaucoma therapy be started in one or both eyes? What should be done if tx is not tolerated?

A
  • Start in one eye, if tolerated treat both

- If not tolerated, switch to alternative agent (sometimes same class but different formulation)

25
Q

What should be done once target IOP is reached?

A
  • Monitor IOP every 2-4 months

- Monitor visual field and optic disc once yearly

26
Q

What is the drug therapy for closed angle glaucoma?

A
  • Pilocarpine (CI in papillary block)
  • Hyperosmotic agents (mannitol; short term tx)
  • Beta blockers, alpha 2 agonsits, prostaglandins, CA inhibitors
27
Q

What happens if IOP is greater than 60 mmHg? What would be the recommended tx?

A
  • Iris may be eschemic and unresponsive to miotics

- Lower IOP first using other agents then use pilocarpine

28
Q

When are mydriatic agents used?

A

Eye examination

29
Q

When are cycloplegic agents used?

A
  • Accurate refractions

- Provide relief from ciliary spasm during inflammation

30
Q

Are oral parasympathoplegic and sympathomimetic drugs used for glaucoma?

A

No, contraindicated in glaucoma

31
Q

What is cataracts?

A

Clouding of crystalline lens

32
Q

What is the lens made up of?

A

Water and proteins arranged in a manner that keeps the lens clear and lets light pass through unimpeded

33
Q

What are the 3 types of cataracts?

A

1) Subcapsular – back of lens; greater risk in diabetics or those taking high doses of steroids
2) Nuclear – forms deep in central zone (nucleus) of lens; associated w/ aging
3) Cortical – characterized by white, wedge-like opacities that start in periphery of lens and work their way to center in a spoke-like fashion

34
Q

What is the most common cause of cataracts? What are some other causes?

A
  • Aging
  • Prolonged use of corticosteroids, statins, phenothiazines
  • Inflammation
  • Trauma
  • Radiation exposure
  • Systemic disease
35
Q

What are the clinical sx of glaucoma?

A
  • Reduced vision
  • Glare while driving during day and at night w/ headlights
  • Dulling colours
  • Double images
36
Q

What is the preferred surgery for cataracts?

A

Phacoemulsification

37
Q

What medications are used for post-op cataract care?

A
  • Antibiotic drops (moxifloxacin 0.5% 1 drop QID for 1 week)
  • NSAID drops (diclofenac 0.1% 1 drop QID for 1 week)
  • Corticosteroid (prednisolone 1% 1 drop QID for 1 week, then BID for 2 weeks)
38
Q

What are som post-op cataract complications? Which is most common?

A
  • Most common = posterior capsule opacification

- Uveitis (persistent inflammation in anterior chamber beyond 4 weeks)

39
Q

What is the most bothersome cause of uveitis?

A

Infectious endophthalmitis

40
Q

What are sx of infectious endophthalmitis?

A
  • Worsening redness
  • Pain
  • Photosensitivity
  • Decreasing vision
41
Q

What is the tx for infectious endophthalmitis?

A

Antibiotics

42
Q

What are signs that IOP has spiked post-cataract operation? What drug is used for this?

A
  • Redness
  • Pain
  • Photophobia
  • IOP > 35 mmHg
  • N/V
  • Beta blockers are drug of choice; avoid prostaglandins
43
Q

What is the tx for posterior capsule opacification?

A

YAG capsulotomy (creates a hole in posterior opaque membrane)

Clinical - Winter (24 decks)

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