SAQ Flashcards
1
Q
Trans corneal diffusion
A
- Ratio of charged and uncharged drug has to be preserved on both sides
- Uncharged can pass through the epithelium into stroma
- Charged molecules left behind become uncharged to maintain ratio and pass through to the storma until all the drug passed through epithelium
- Inside stroma, some of drug becomes charged and passes through stroma
- Charged molecules become uncharged on the other end to preserve ratio and pass through endothelium
- Uncharged molecules become charged in endothelium
2
Q
How to choose administration routes
A
Target tissue Speed of action Stability of drug Duration of action Solubility in water Physiology of patient Comorbidities Age, compliance
3
Q
Legal classification
A
GSL - general sales list
P - pharmacy medicine
POM - prescription only medicine
4
Q
Pharmacological classification
A
Mode of action
Chemical composition
Effect of drug
5
Q
Pupil pathway
A
Autonomic nervous system:
- sympathetic
- parasympathetic
6
Q
Sympathetic
A
- Stimulates
- adrenergic stimulation and blockers
7
Q
Ocular uses of adrenergic stimulation in sympathetic
A
- dilation
- testing for oculosympathetic lesions eg horners syndrome
- constrict conjunctival vessels
- relief of minor allergic reactions
8
Q
Ocular uses of adrenergic blocking in sympathetic
A
- beta blockers: control IOP
- alpha blockers: reverse dilation
- for pupil miosis
9
Q
Parasympathtic nervous system
A
- cholinergic blocking:
Prevents miosis of pupil causing dilation
Paralyses accommodation
10
Q
Sympathetic
A
Carotid artery - 6th cranial nerve - ophthalmic division of 5th CN - ciliary ganglion - long ciliary nerve - IRIS DILATOR MUSCLE AND MUELLERS MUSCLE
11
Q
Parasympathetic
A
Edding westphal nucleus - 3rd nerve - ciliary ganglion - IRIS SPHINCTER
12
Q
Indications for mydriasis (dilation)
A
- flashes floaters
- sudden vision loss
- progressive cataracts/ other media opacities
- small pupils
- ocular surgery
- imaging
- px with risk of retinal diseases
- high myopes
13
Q
Mode of action for mydriatics
A
- SYMPA: DIRECT AGONIST: alpha and beta receptors stimulate contraction of IRIS DILATOR MUSCLE
- PARA: DIRECT ANTAGONIST: block SPHINCTER MUSCLE
14
Q
Tropicamide
A
- muscarinic antagonist (blocks sphincter muscle - para)
- anticholinergic
- POM
15
Q
Ocular side effects TROPICAMIDE
A
- transient stinging
- elevation of IOP
- photophobia
- blurred vision
16
Q
Systemic side effects of TROPICAMIDE
A
- less severe than cyclopentolate and atropine
- safest
- ask px to bring sunglasses
- px not drive or operate machinery
17
Q
Phenyephrine
A
- sympathimimetix amine
- stimulates iris dilator muscle via alpha receptors
- POM
18
Q
Ocular side effects:
A
- pain
- teary
- keratitis
- pigmented aqueous floaters
- rebound miosis
- rebound conjunctival congestion
- conjunctival hypoxia
19
Q
Systemic side effects
A
- hypertension
- occipital headache
- subarachnoid haemorrhage
- ventricular arrhythmia
- tachycardia
- blanching of skin
- reflex bradycardia
20
Q
Cautions when using mydriatics
A
- allergies
- angle closure or narrow angles
- iris mounted IOLs
- new born babies
Tropicamide: angle closure glaucoma
Phenylephrine: hyperthyroidism, asthma, diabetes, stroke, other meds
21
Q
Mode of action for Miotics (constrict)
A
- DIRECT CHOLINERGIC AGONIST
- indirect cholinergic agonist
- adrenergic antagonist
22
Q
Pilocarpine POM
A
- 1,2,4 % minims
- pupil miosis
- spasm of accommodation
- reduce IOP
23
Q
Contraindications of pilocarpine
A
- known sensitivity
- uveitis/ iritis
- iris mounted iol
- fragile iris
- retinal detachment
- exfoliation syndrome
24
Q
Cyclopegics
A
- relax accommodation
- block acetylcholine at iris sphincter muscle and ciliary body
- use for: strabismus, children and infants, young hyperopia
25
Which one is most potent (powerful)
- AHCT
- atropine (most)
- homatropine
- cyclopentalate
- tropicamide (least)
26
Atropine
- available to optoms with additional supply or independent prescriber
- complete paralysis of accommodation
- amblyopia
27
Cyclopentalate
- optoms use in practice
- dark skin and iris can resist cyclopegia
- light eyes: 0.5% -20mins
- brown eyes: 1% -30/40 mins
- children: 1%
28
Cyclopentalate ocular effect
```
Irritation
Lacrimation
Conjunctival hyperaemia
Allergic blepharo-conjunctivitis
Elevated IOP
```
29
Cyclopentalate systemic effect
```
Drowsiness
Ataxia
Disorientation
Incoherent speech
Restlessness
Visual hallucinations
```
30
Sodium fluorescein
- not true dye
- max absorption : 493nm
- emits at 520nm
- 1 %, 2%,
- 0.25% with 4% lidocaine
- use before any topical anaesthetics
31
Uses of fluorescein
```
RGP fitting
Tear film assessment
Corneal observations
Foreign bodies/stray CLs
Corneal staining
Contact Tonometry
Angiography
Assess nasolacrimal drainage system
Jones dye test
Seidel rest
```
32
Rose Bengal
```
True stain
Stains dead cells
Maybe causes cell damage
Not available in uk
Stings
Viewed with white light
Instil and then wash away excess with saline
Stings more than lissamine green
Bind to unprotected corneal epithelial cells
```
33
Uses of rose Bengal
- Diagnose dry
- Evaluate corneal and conjunctival lesions
- differentiate between HSV and HZV
34
Lisaamine green
```
True dye
Conjunctival staining for dry eye
Good at identifying Marx line
Impregnated strip with 1.5mg of dye
Into lower fornix
Viewed with white light
Bind to unprotected corneal epithelial cells
```
35
Dry eyes assessment
S ubjective
O bjective
A ction
P lan
36
Artificial tears legal classification
P, POM, GSL
37
Hypromellose (P)
4 times a day
Thin watery
Low viscousity
Used preserved
38
Factors affecting eye drop bioavailability
```
Drug dosage
Drug formulation and design
Corneal integrity
Topical anaesthetics used?
Iris pigmentation
Physiological features of px
```
39
Compare and contrast delivery modes of ocular drugs
Eye drops and eye ointments
| See pictures
40
Anaesthetics actions
It’s an antagonist - blocks sodium channels
Nerve fibres:
Pain - touch - temperature - pressure
Softens cornea (affect IOP)
Reduce blink rate
Delay cell regeneration
41
Uses for anaesthetics
```
Contact tonometry
Foreign body removal
Punctual plugs
Eye impression
Diagnostic procedures
Irrigation of the eye
```
42
Contraindications for anaesthetics
```
Known hypersensitivity
Premature babies
Global penetrating injuries
Pregnancy and breastfeeding
Where wound healing would be compromised
```
43
Which ones stings least
POLT
Proxymetacaine (least)
Oxybuprocaine
Lidocaine
Tetracaine (most)
44
Proxymetacaine (0.5%)
- less punctate staining than tetracaine
- stings least
- more potent than tetracaine
- stored in fridge
```
Uses:
Tonometry
Deep anaesthesia
Removal of sutures
Remove foreign bodies
```
45
Oxybuprocaine 0.4%
- produces less punctate staining than tetracaine
- stored room temperature
Use:
Tonometry/CLs
Foreign body removal
46
Lidocaine 4% with fluorescein 0.25%
Useful:
- contact Tonometry
- if pc has adverse reaction to any Esther anaesthetic group
47
Tetracaine (0.5% and 1%)
Above 1% can damage cornea
| Not used on pc with known hypersensitivity
48
Analgesia - painkillers
Non-opioid:
- paracetamol
- aspirin
- ibuprofen
Opioid:
- morphine
- methadone
- tramadol
- codeine
49
Nonsteriodals anti inflammatory (NSAID)
Ocular painkiller
50
Selection of drop for glaucoma
```
HReduction of IOP
Duration of effect
Preservation of visual field
Maintenance of effect
Compatibility with other medication
Lack of topical side effects
Lack of systemic side effects
Patient compliance
```
