Occular pharm and physio Flashcards
What are the 2 barriers that drugs have to cross in the eye
Blood retina and blood aqueaous
What can you give patients with thyroid eye disease
IV methylprednisalone to prevent optic neuritis
What is Sjogren’s syndrome?
Autoimmune condition which destroys lacrimal glands
Is the corneal epithelium hydrophobic or philic
Phobic, so drugs have to be fat soluble to get through.
What are the two cell layers in the blood aqeuous barriers
Vascular endothelium and non pigemented cilliary epithelium
What are the 2 cell layers in the blood retina barrier
Retinal capillary endothelial and retinal pigment epithelial
Where in the eye are muscarinic and nicotnic receptors found?
EOM Levator palpabrae superioris Iris sphincter iris sphincter muscle Ciliary body Lacrimal gland
What is choline acetyltransferase and where in the eye is it found?
It degrades ACh and is found in the corneal epithelium, ciliary body, inner plexiform layer of the retina
What do cholinergic agonists / parasympathomimetics (pilocarpine) do
Increase drainage, miosis and accomodation
How is ocular myasthenia diagnosed and treated
Tensilon test - give IV edrophonium and see if ptosis and diplopia improve. Give neostigmine for treatment
What do cholinergic antagonists do (tropicamide)
Mydriasis, cyclopegia (prevents accomodation), decreases lacrimal secretion
What are they used for
Prevent posterior synachia in uvetitis and iritis, and this means the iris is attached to the lens
Explain the sympathetic trunk
Runs from T1 to L2. Pre ganglionic neurotransmitter is Ach, post is adrenaline and noradrenaline. They act on alpha and beta receptors to cause pupil dialtion and
Name some alpha agonists and their side effects
Clonidine. Allergic conjuctivitis, conjunctibal blanching, hypotensions and dry mouth
What else can this be used for
Differentitae between scelritis and episcleritis - This will cause constriction of the episcrel vessels in episcelritis - you can see blanching
Where in the eye can carbonic anhydrase be found
ciliray body epithelium
What is the general combination treamtne for glaucoma
carbonic anhydrase inhib and beta blockers
What does the aqueaous layer of tears have
Ig A and lysozymes to clear the eye
Explain the parasympathetic innervation of the iris?
Light impulse travels down to the Edinger Westphal nucleus which is the parasympathetic pre ganglionic nucleus. This then triggers the Occulamotor nerve (CN3) to the ciliary ganglion to cause pupilary constriction.
