Practical 1: Drugs on the eye Flashcards
which type of nervous system plays a role in the control of processes in the eye
the autonomic nervous system
describe what happens to the eye under bright conditions
parasympathetic nerve impulse circular muscles (of iris) contract radial muscles relax pupil constricts less light enters eye
pupil constriction involves which neurotransmitter and receptor
acetylcholine released from parasympathetic nerve endings will bind to muscarinic M3 receptors causing the circular muscles of the iris to contract
describe what happens to the eye under dim light
sympathetic nerve impulse circular muscles relax radial muscles contract pupil dilates more light enters the eye
which neurotransmitter and receptor are involved in pupil dilation
adrenaline is released from sympathetic nerve endings and binds to alpha-adrenoreceptors causing the radial muscles of the iris to contract
when clinicians want to examine the retina in detail what eye drops do they use
eye drops that are antagonists at muscarinic receptors to dilate the pupil
the autonomic nervous system also allows the eye to accommodate for near vision. How
by adjusting the curvature of the lens via the ciliary muscle and the suspensory ligaments
describe accommodation when focusing on distant objects
the ciliary muscles relax to allow the suspensory ligaments to pull on the lens, making it thinner
describe accommodation when focusing on near objects
the ciliary muscles contract releasing tension on the suspensory ligaments allowing the lens to bulge more
contraction of the ciliary muscle is controlled by which type of nervous system and neurotransmitter
parasympathetic nervous system anf acetylcholine
what type of drugs will affect the ability of the eye to accommodate
drugs which are agonists or antagonists at the muscarinic M3 receptors
this is a band 2 practical, which means
medical supervision is required
can contact lens users take the eye drops
soft lenses: no unless they take them off and keep them out until the class is over. could be gas permeable and concentrate the drug out of solution and then act as a reservoir hard lenses: can use
students driving or cycling after can take
phenylephrine but not tropicamide or pilocarpine
what are contraindications
we must ensure drugs do not effect any pre-existing medical conditions students possibly have
what are cautions
must ensure drugs don’t increase the risk of unwanted effects in certain students eg pregnant or diabetics
what are interactions
must ensure drugs don’t interact with any medicines students may be taking
when giving the eyedrops why should the patient avoid blinking
blinking cuases the medication to flow into the nasolacrimal duct
how else can we aso minimise drainage of the drug into the nasolacrimal duct
occluding ( blocking) the punctum after instillation of the drug
what is the pupil gauge used for
to measure pupil size
what is the pen torch used for
to measure pupillary response to light, speed of response
what is the near point rule used for
to measure near vision
what are reading books used for
to see which passage is read the most comfortably
what is the Snellen test used for
successfully read off the chart. 6/
