Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

DEP > pharmacology of eye > Flashcards

pharmacology of eye Flashcards

(54 cards)

Start Studying
1
Q

routes of administration in eye

A

extraocular - topical the most common

intraocular

peri-oculat

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

what does the extraocular route target

A

anterior segment

cornea
sclera
conjunctiva
iris
ciliary body
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

the major route of absorption of the eye when given extraocular

A

cornea

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

examples of intraocular route meds

A 
Intravitreal injections
e.g. Anti-VEGF
injections
(ranibizumab) for
proliferative diabetic
neuropathy and wet
AMD.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

peri-ocular route targets

A

peri-bulbar
retrobulbar injections
subtenons block

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

which medications in opthamology take the systemic route

A

steroids
carbonic anhydrase inhibitors
ABx

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Pts presenting with papilloedema
secondary to raised ICP or acute angle
closure glaucoma are treated with

A

IV acetozolamide to reduce IOP

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

Patients with severe active thyroid eye

disease can be treated with

A

IV methylprednisolone to reduce inflammation and prevent optic neuritis

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

advantages of ABx

A
  1. Less invasive mode of delivery
  2. More pleasant for patient
  3. Reduced infection risk compared
    to injections
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Disadvantages of ABx

A
  1. Needs to penetrate blood-retinal
    and blood-aqueous barrier
  2. High doses can cause systemic side effects
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

most common route of administration

A

into the inferior fornix

foreign bodies may be hid in the superior fornix

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

bioavailability of drug is affected by what

A

corneal and precorneal factors

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

what are the precorneal factors and how does it affect the bioavailability

A

solution drainage - Once in the fornix the drugs drain through the
nasolacrimal duct to enter the inferior meatus through
the valve of Hasner. Here a substantial amount is
absorbed by the nasal mucosa into the blood stream:

blink rate 15p per minute

tear volume adn tear turnouver rate -> 7/8uL
can be altered by - blink rate and lacrimation

induced lacrimation
- inflammation
- Light
• Temperature
• Additional environmental factors

tear film
- structure of tear film is altered ie meiobian gland dysfunction - reduced drug residency time in fornix

  • pH of tear film ->6.5-7.6 - altered can affect diffusion
  • might bind to tear film proteins - albumin and lysozyme
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

layers of the cornea are bound by

A

desmosomes

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

which layer of cornea is hydrophobic and which layer allows ionised water soluble drugs

A

epithelium is hydrophobic - lipid soluble drugs

stroma - type 1 collagen, permites ionised water soluble drugs

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

endothelium allows aqueous humour how

A

gap junctions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

2 major ocular barriers to drugs

A

blood - aqueous barrier

blood - retinal barrier

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

what is the blood - aqueous barrier

A

Two discrete
cell layers located in the anterior segment of
the eye:

  1. The vascular endothelium of the iris/ciliary
    vessels
  2. The non-pigmented ciliary epithelium

prevent the entry of soutes into the anterior segment

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

what is the blood-retinal barrier

A

(BRB) restricts the entry of
the drugs from blood into the posterior segment.
It is composed of two types of cells :

  1. The retinal capillary endothelial cells (inner BRB)
  2. The retinal pigment epithelium cells (outer BRB)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

what is the outer BRB (RPE)

A

RPE: The outer retinal layers
are nourished by the choroid.

• Nutrients/drugs enter the systemic
circulation and eventually reach the
vascular choroid.

• RPE tight junctions restrict diffusion from
choroid to the outer retinal layers.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

what is inner BRB

A

The inner retinal layers are
nourished by the retinal vessels.

• Diffusion from the retinal vessels is
restricted by tight junctions in the
endothelium.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

which receptor do acetylcholine bind to in PS Ns

Study These Flashcards
A

Muscarinic receptors located on post-
ganglionic effector organ

Nicotinic receptors located on ganglion
synapses and NMJ

23
Q

The ocular receptor are found where

Study These Flashcards
A

EOM
Levator palpabrae superioris
Iris sphincter

Iris sphincter muscle
Ciliary Body
Lacrimal gland

24
Q

what is choline acetyltrasferase and where is it found

Study These Flashcards
A

responsible for degrading Ach

  1. Corneal epithelium
  2. Ciliary body
  3. Inner plexiform layer of the retina
25
actions of cholinergic agonists
reduce IOP - opening trabecular meshwork to allow aqueous drainage accomodation - stimulate ciliary muscle and open outflow pathway miosis (pupil constriction) - stimulates iris sphincter muscle
26
examples of direct parasympathomimetic and indirect parasympathomimetic
Direct parasympathomimetic: Pilocarpine. Used frequently in the treatment of glaucoma. ``` Indirect Parasympathomimetic (Inhibit Acetylcholinesterase and prevent breakdown of Ach): Edrophonium, Physostigmine. ```
27
how to test for ocular myasthenia
made using the Tensilon Test. IV is edrophonium is administered. Any improvement in ptosis or diplopia confirms a positive diagnosis. Longer acting neostigmine can be used for treatment
28
SEs of parasympathomimetics
Systemic –salivation, bradycardia Ocular – cataracts iris cysts, conjunctival toxicity
29
actions of cholinergic antagonists
mydriasis (pupil dilatation) - inhibits sphincter pupillae) cycloplegia - inhibits ciliary muscle contraction - NO ACCOMMODATION slightly decreased lacrimal secretions
30
how are sympathomimetics used in uveitis and iritis
prevent the formation of posterior synaechiae - adhesions between the posterior iris and anterior lens surface
31
uses of cholinergic antagonists
Prevent posterior synechiae • Routine fundal exam • Provocation of glaucoma (test)
32
types of cholinergic antagonist time to onset of action time of effect
Atropine 40 mins 7-10 dyas Cyclopentolate 30 mins 12-24 hours Tropicamide 20 mins 3-4 hours
33
SEs of cholinergic agonists
Systemic – sweating, flushing, tachycardia Ocular - blurred vision, photophobia, glaucoma,
34
what is the sympathetic outflow trunk
T1-L2
35
what is the role of alpha agonists
Smooth muscle contraction • Dilator pupillae muscle • Ciliary muscle • Constriction of conjunctival and episcleral vessels
36
role of beta blockers
- increase aqueous outflow | - decreased aqueous production
37
types of topical alpha agonists
apraclonidine brimonidine clonidine
38
SEs of alpha agonists
Common: allergic conjunctivitis, conjunctival blanching Systemic: hypotension, dry mouth
39
types of beta blockers
timolol betacolo levobunolol
40
where are Beta 2 receptors found
ciliary processes trabecular meshwork
41
MOA of carbonic anhydrase inhibitor
Inhibit carbonic anhydrase which is found in ciliary body epithelium. It is a key enzyme in aqueous production
42
types of topical CAIS
acteozolamide (IV/PO) dorzolamiode brinzolamide topically as have adequate corneal penetration
43
SEs of CAIs
Systemic: renal stones, malaise, fatigue Ocular: stinging, allergic reactions
44
function of the aqueous
1. supply nutrition to the lens, corneal endothelium, corneal stroma BUT NOT CORNEAL ENDOTHELIUM 2. Maintain IOP -determined bu the rate of aqueous secretion and rate of aqueous outflow 10-21 mmHg 3. remain transparent
45
aqueous humor pathway
secreted by ciliary body epithelium into the posterior chamber Aqueous flows through the pupil into the anterior chamber • Aqueous can be drained through the trabecular outflow (90%) or uveoscleral outflow (10%) • Trabecular: trabecular meshwork, Schlemm's canal, episcleral veins • Uveoscleral: Drained by the venous circulation in the ciliary body, choroid and sclera
46
tear film layer and role
lipid layer - • Smooth surface for lids to glide over • Reduces surface tension and draws water into the tear film • Prevents evaporation of the aqueous layer Antibacterial IgA and lysozyme • Transfers oxygen to the avascular corneal epithelium • Abolishes surface irregularities of the cornea mucous layer ‘Wets’ the cornea and lubricates it. Essentially attaches the aqueous to the corneal epithelium. epithelial layer
47
role of orbicularis oculi pump
• 70% tears drained by the lower canaliculus. Remainder drained by the upper. • With each blink fibres of orbicularis shorten the canaliculi and move the puncta medially. The lacrimal sac expands creating negative pressure and drawing in the tears • When the eyes open and the muscles relax, the sac collapses and tears drain down the ducts
48
light stimulus pathway
• Light stimulus • EDW nucleus is the PNS preganglionic nucleus. • Fibres travel in CN III and synapse in the ciliary ganglion * Short ciliary nerve * Sphincter pupillae
49
what is accomodation
Accommodation occurs when the eyes are directed from a distant object to a near object
50
accommodation reflex
- Convergence of the eyes - Pupillary constriction - Increased biconvexity of the lens
51
when does accommodation develop and when does ones ability decrease
develops at 2 months and is well developed at 8 months decrease with age and by 60 years is extrememly poor presbyopia
52
how is convergence obtained in accommodation
contraction of medial rectus via innervation | by oculomotor nerve
53
how is pupillary constriction achieved in accommodation
contraction of sphincter pupillae
54
how is increased lens biconvexity achieved
``` Circular ciliary muscle contracts, decreasing tension in zonular fibres, and allowing the lens capsule to contact and change the shape of he lens. The anterior pole moves forward, the axial width increases and the diameter of the lens decreases. ```

DEP (20 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions