mydriatics, cycloplegics, anaethetics and stains Flashcards
why do we use mydriatics
- allows a more thorough examination of the eye e.g. peripheral crystalline lens, vitreous and fundus
- facilitates a stereo fundus exam
- for treatment
when do we use mydriatics
- on patients at risk of retinal detachment
- symptoms
what type of symptoms would a px show for us to use mydriatics
- unexplained vision loss/ vf loss or disturbance
- floaters, flashes, veils, shadows
what patients are at a risk of retinal detachment
- high myopia (> -5.00D)
- family history
- trauma
when else would we use mydriates
- screening: diabetes, prior to ocular surgery
- inadequate fundus view: lens/media opacities, miotic pupil
benefits of mydriatics
- rapid onset
- adequate duration
- fast recovery
- no adverse effects
- light reflex abolished
- no rise in IOP
what do we do prior to dilation
- ensure we have good reason to use the drug
- explain procedure
- px consent
- issue written information
- advise effects- glare, loss of stereo vision, driving, operating machinery
- minimise risk of adverse reaction
- check for contraindications
- 4D test: Drug, Dosage, Date, Disposal + time
method of instillation of myrdriatic
- ask px to look up
- pull down lower lid
- instill a drop into lower conjunctival sac
- occlude puncta to avoid drainage into nasolacrimal duct
- record drug, strength, dosage, expiry date, batch number and time of instillation
what are some general contraindications
- sensitivity to drug
- narrow angles
- if they have iris clip IOLs
- px with symptoms of sub-acute or chronic closed-angle glaucoma
- px diagnosed with CAG
- px using pilocarpine for glaucoma treatments
CAG after tropicamide; what symptoms would they have?
- blurred vision
- haloes
- headaches
- pain
- nausea
- photophobia
- closed angle
- fixed mid-dilated pupil
- cloudy cornea
- conjunctival hyperaemia
- sudden increase in IOP
checks to minimise risk of CAG
- IOP; pre and post dilation
- anterior angles
- existing symptoms
- reverse continued increase of IOP with miotic drug
examples of muscarinic antagonists mydriatics and how often used
tropicamide - mostly used
cyclopentolate - rarely used as mydriatic
atropine- unlikely to be used as mydriatic and only available to independant prescribers
examples of sympathomimetic mydriatics
phenylepherine - used more in USA
autonomous nervouse system branches
parasympathetics: inhibits body from overworking
sympathetics: fight or flight
what is the main transmitter in the parasympathetics nervous system
acetylcholine
what receptor does the parasympathetic work on
muscarinic
what muscle in the eye does parasympathetic work on
ciliary and sphincter
