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PHA 222 > glaucoma 1 > Flashcards

glaucoma 1 Flashcards

1
Q

what is glaucoma?

A

Glaucoma is a group of eye diseases that can lead to blindness if untreated

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2
Q

what is the Palpebral fissure?

A

the space between the two eyelids. the narrow side is called the lateral angle and the side closer to the nose is called the medial angle.

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3
Q

describe the flow of tears?

A

tears are produced in the lacrimal gland.
it is then transported from Lacrimal ducts>Superior or inferior lacrimal> canal Lacrimal ducts>Nasolacrimal duct>Lacrimal sac>Nasal cavity

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4
Q

what is another name for the upper and lower eyelid?

A

palpebra

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5
Q

how many layers are there in the eye?

A

3 layers- sclera, choroid and retina

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6
Q

what do the Zonula fibers do?

A

they are suspensory ligaments attached to the lens. if they move so do the lens.

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7
Q

what is another name for the optic disk?

A

blind spot

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8
Q

what part of the retina does the visual axis lye on?

A

Fovea centralis

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9
Q

how is the aqueous humour formed?

A

Aqueous humouris formed by capillary network in ciliary body

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10
Q

where us the aqueous humor drained?

A

Drains into the canal of Schlemm,>Eventually enters the blood

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11
Q

what is the drainage of aqueous humor balanced by?

A

balanced by the rate of secretion. and because of this the IOP is maintained at 10-20mmHg

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12
Q

when is the IOP at max and min?

A

IOP maximum - 8.00 -11.00am; minimum -midnight -2.00pm

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13
Q

what is the The production of aqueous humour is indirectly related to ?

A

blood pressure and blood flow in the ciliary body

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14
Q

how much aqueous humour is formed every minute?

A

3 microlitres per minute

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15
Q

what is the fate after it enters the anterior chamber?

A

10%- Uveoscleral outflow tract

90%- Episcleral veins(venous plexus)

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16
Q

what is the adrenergic receptor response in the: Iris radial muscle, ciliary epithelium ,Ciliary muscle and Lacrimal gland?

A

iris radical muscle- A2-Mydriasis-dilation of pupil
ciliary epithelium- A2/B2-Aqueous humour production
Ciliary muscle-b2- relaxation
lacrimal gland-A2- secretion

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17
Q

what is the Cholinergic receptor subtype and response in :Iris sphincter muscle, ciliary muscle and lacrimal gland?

A

m3- miosis
m3- accommodation
m2/3- secretion

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18
Q

how many types of glaucoma are there? and what are they?

A 
5
1-Chronic open – angle glaucoma (COAG)
2-Normal tension glaucoma
3-Ocular hypertension (OHT)
4-Primary angle –closure glaucoma (PACG)
5-Secondary  glaucomas
19
Q

what is COAG?

A

Relative obstruction of aqueous outflow through the trabecular meshwork, usually affects both eyes

20
Q

what is normal tension glaucoma?

A

IOP not raised on initial screening although signs of damage are present

21
Q

what is OHT?

A

Elevated IOP in absence of visual field loss orglaucomatous optic nerve damage

22
Q

What is PACG?

A

Closure of the angle by peripheral iris results in reduction of aqueous outflow.
mostly in women

23
Q

what is secondary glycomas?

A

Arise for a number of reasons (inflammation, intraocular tumour, raised episcleral pressure or congenitally due to developmental abnormalities)

24
Q

how is glaucoma caused?

A

caused by poor drainage of aqueous humour and can cause blindness

25
Q

how is glaucoma characterised?

A

Increase in IOP to more than 21mmHg
•Changes in the fundus , in particular optic disk ‘cupping’
•Visual field changes
•If untreated , glaucoma permanently damages the optic nerve and this can cause blindness

26
Q

what are Ocular Prostanoids?

A

ester compounds that cause a fall in IOP by increasing the uveosleral outflow with no significant effect on other parameters of aqueous humour

27
Q

what does Lasanoprost do?

A

it is an ocular prostanoid that :converted to its active free acid on entering the eye
administered in the evening

28
Q

what does Travosprost do?

A

Ester prodrug converted to its active form by cornealhydrolytic enzymes as it is absorbed from the eye
•Potent full agonist of PGF2α- receptor

29
Q

what does Bimatoprost do?

A

Fatty acid amide similar to PGF2α1-ethanolamide

•Lowers IOP to a greater extent than any topicalocular hypotensive which is sustained for at least 4years

30
Q

what do b-blocker adrenoreceptor agonists do?

A

Blocked of ciliary β-receptors , preventing the cyclic AMP –induced rise is aqueous secretion.
•Reduce aqueous humour formation rather than increase outflow

31
Q

what is seen in Beta –adrenoceptor antagonists?

A

bradycardia
Episodes of orthostatic hypotension & syncope in elderly
bronchospasm

32
Q

what are the two sympathetic agents used?

A

Apraclonidine

Brimonidine

33
Q

how does Apraclonidine work?

A

•α2-selective agonist ; in high conc. activates α1-receptors

  1. Activation ofα2–dec ciliary body aqueous humor
  2. Activation of α1- dec ciliary blood flow
  3. Activation of postsynaptic α2- autoreceptors-dec NA release aqueous humour following diminished postsynaptic βreceptor stimulation
34
Q

how does brimonidine work?

A
  • More α2- selective
  • Results in miosis rather than mydriasis
  • Used alone or adjunct to β–blockers & PGA
  • dec aqueous humour production & increase uveoscleral flow
35
Q

when is Brimonidine used in caution?

A

Used with caution severe coronary artery disease

and Contraindicated in patients taking MAOIs , TCA

36
Q

what is Pilocarpine?

A

it is a miotic

Stimulation of ciliary muscle- increases outflow of aqueous humour & opening of channels of trabecular meshwork

37
Q

why is Pilocarpine not patient compliant

A

Onset of action 19 mins.; Short duration of action ; 4times daily- therefore, mainly used in secondary glaucoma

38
Q

how many forms of Carbonic anhydrase inhibitors are present in the eye? and what are they?

A

3 forms

CA1,CAII AND CAIV

39
Q

how do Carbonic anhydrase inhibitors work in the eye?

A

inHibit CAII
Formation of bicarbonate ions and their secretion Into the posterior chamber
2. DECREASED sodium transport into posterior chamber
3. Lowering IOP

40
Q

Are carbonic anhydrase inhibitors used in combination?

A

yes- for a more desired effect

41
Q

what hyperosmotic agents are used and why?

A

glycerol orally and mannitol IV due to their speed of action and effectivenss in an emergency

42
Q

after administration of a hyperosmotic agent what happens?

A

inc in plasma osmolarity
net water movement
reduced IOP

43
Q

why is PACG a medical emergency?

A

Without treatment blindness may occur in 1-2 days

•Usually a permanent cure is produced by lasersurgery

PHA 222 (41 decks)

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