Cycloplegics Flashcards
(34 cards)
What happens as get older
Accommodation reduces
What does duanes classical curve show
Amplitude or width of accommodation as changing with age = declines as older
Why use cylcoplegics
Optometric uses
*Assessment of refractive error - latent hyperopia = accommodative muscles are used to increase the eyes focusing power
*Penalisation - instead of occlusion
*Adaptation to spectacles (rare) – vision clear only with glasses
Additional ophthalmological uses
*Anterior uveitis – dilating pupil and alleviating ciliary spasm
*Corneal abrasion - alleviate ciliary spasm
What optometric indications would make you want to use cyloplegics
From H and S
- Symptoms
- Asthenopia = fatigue, blurred vision, pain in eyes
- Reading difficulties
- History
- Manifest deviations
- Family history
- Refractive error at an early age
-Manifest deviations
From clinical tests:
- Binocular vision anomaly
- Manifest eso deviation Sometimes if latent deviation
- Fluctuating ret
- Large difference between subjective and objective
- Poor fixation
- Accommodative anomalies
- Visual acuity reduced
Properties of a cycloplegic
- Rapid onset
- Adequate depth of cycloplegia
- Adequate duration
- No stinging
-No mydriasis - No toxic effects – Local AND systemic
- Large pupil
- Drops sting / duration of onset of cycloplegia
- Unnatural conditions
Effects of cycloplegia - how is cycloplegia caused
- Initially mydriasis
- Iris located anteriorly to ciliary muscle
- Unnecessary side effect - Cycloplegia
- Paralysis of the ciliary muscle, resulting in loss of accommodation
- Because of the paralysis of the ciliary muscle, the curvature of the lens can no longer be adjusted to focus on near objects
- Paralysis of the ciliary muscle, resulting in loss of accommodation
- Reduced tear secretion = dry eye
Which parts of eye does antimuscarinic agents affect
- Lacrimal gland
- Iris sphincter muscle
- Ciliary body
Advice before instillation
Advice for parent/guardian
* Explain need to use
* Onset
* Duration
* Expected side effects = temporary blurred vision until effects wear off
* Caution
Advice for child
* Explain might feel drop on eye
* 1dropof proxymetacaine first?
– RCOguidelines
What happens if consent is denied
Parent/Guardian:
* Explain advantages and disadvantages
* Note refusal on record
* If concern for child great refer to GP
Child
* Gillick competent = child agrees
* Record all discussions on notes
* If concern for child great refer to GP
How to instil drops
- Instillation-lying down may help.
- Sometimes drop onto eyelashes can help
Checking for cycloplegia
*Measure accommodation
*Check ret reflex
Cycloplegic Retinoscopy
- Sit younger child on parent’s knee
- Can ask px to fixate upon light of ret
– Ensures retinoscopy is conducted upon axis - No need to fog other eye
- Can try using lens rack
- Observe central movement – 3-4mm
- Ignore movement in periphery
Examples of cycloplegic drugs
Strongest to weakest:
- Atropine 1%
- Additional supply or independent prescriber status
- Associated with numerous side effects
- Cyclopentolate
- 0.5 and 1%
- Most commonly used
-Homatropine 1%
- Additional supply or independent prescriber status
- Tropicamide 1%
- Weakest drug only effective in adults
- Used mainly as mydraitic
Features of atropine sulphate
- Naturally occurring compound “Belladonna” deadly nightshade
- First muscarinic antagonist used in medicine
- Toxic agent
- POM = For use and supply by additional
supply optometrists and used and prescribed by independent prescribing optometrists
Atropine- Preparations
- Atropine Sulphate: eye drops, (non-proprietary)
– 0.5% atropine sulphate
– 1.0% atropine sulphate - Atropine Sulphate: eye ointment
– 1% atropine sulphate (non- proprietary) - Minims
- 1% atropine sulphate (Bausch &
Atropine- Dose
Adults and children > 3 months
*Eye drops
– 1 drop (1%) twice per day for 1-3 days before refraction
*Ointment
– 2 times a day for 1-3 days before refraction
Why is atropine ointment preferable
– Systemic toxic effects
– Prolonged contact with eye
Atropine -Timing
After instilling 1 drop of 1%:
Mydriasis
–Commences in 10-15 mins
–Maximal in 30 – 40 mins
–Recovers in 3 – 7 days
Cycloplegia
–Commences in 30 mins
–Maximal in 1 – 3 hours
–Recovers in 3 - 7 days
After 3x twice daily instillations
Mydriasis
–Recovers after 10 – 14 days
Cycloplegia
–Recovers after 7 – 10 days
–Adequate near vision recovers after 4 – 5 day
Atropine-Tonus allowance
- Ciliary muscle has dependant and independent tone
- Allowance needs to be made for dependent tone - Spherical power only needs to be adjusted in less
positive direction - -1.00DS for low myopes and hyperopes
- 0.00DS for moderate and high myopes
Atropine - Cautions
Contraindications
- Known allergy to atropine or component of the preparation
- Narrow angles - not so present in children
Cautions
- Children < 3 months
- Elderly or debilitated
- Down’s syndrome
- Children with brain damage
- Hypersensitivity
- Soft contact lenses = multi-dose containers contain benzalkonium chloride – do not use if lenses worn Intermittent manifest deviations
Pregnancy and Lactation Interactions
Atropine Sulphate side effects on eye
- Transient stinging
- Blurring
- Photophobia
- RaisedIOP?
- Repeated use
– Hyperaemia
– Oedema
– Itching, irritation
– Follicular conjunctivitis
Atropine Sulphate side effects on body
- Toxic effects
– Dry as a bone: Dry mouth and skin
– Red as a beetroot: Flushing, Increased body temperature
– Blind as a bat: Cycloplegia
– Mad as a hatter: CNS effects –ataxia, hallucinations, confusion, difficulty in speaking - Tachycardia
- Death from respiratory depression = more likely in children. 3 gram tube can be fatal to a small children
Atropine - additional uses
- Used to treat amblyopia = instead of occlusion
- Instilledinto“better eye”
- Preventsaccommodation
- Used when child will not tolerate patching/ first choice?
- Excellent results
Features of Cyclopentolate Hydrochloride
- Commonly used cycloplegic
- Synthetic drug
- Not commonly used as a mydriatic by Optometrists
*0.5% more useful as a mydriatic
*Ophthalmologists - Stings
